[Federal Register Volume 60, Number 186 (Tuesday, September 26, 1995)]
[Rules and Regulations]
[Pages 49495-49505]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-23803]
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NUCLEAR REGULATORY COMMISSION
10 CFR Part 50
RIN 3150-AF00
Primary Reactor Containment Leakage Testing for Water-Cooled
Power Reactors
AGENCY: Nuclear Regulatory Commission.
ACTION: Final rule.
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SUMMARY: The Nuclear Regulatory Commission is amending its regulations
to provide a performance-based option for leakage-rate testing of
containments of light-water-cooled nuclear power plants. This option is
available for voluntary adoption by licensees in lieu of compliance
with the prescriptive requirements contained in the current regulation.
This action improves the focus of the regulations by eliminating
prescriptive requirements that are marginal to safety. The final rule
allows test intervals to be based on system and component performance
and provides licensees greater flexibility for cost-effective
implementation methods of regulatory safety objectives.
EFFECTIVE DATE: October 26, 1995.
FOR FURTHER INFORMATION CONTACT: Dr. Moni Dey, Office of Nuclear
Regulatory Research, U.S. Nuclear Regulatory Commission, Washington, DC
20555, telephone (301) 415-6443, e-mail mkd@nrc.gov
SUPPLEMENTARY INFORMATION:
Background--Development of Proposed Rule
NRC's Marginal-to-Safety Program
In 1984, the NRC staff initiated a program to make regulatory
requirements more efficient by eliminating those with marginal impact
on safety. The NRC's initiative to eliminate requirements marginal to
safety recognizes both the dynamic nature of the regulatory process and
that the importance and safety contribution of some existing regulatory
requirements may not have been accurately predicted when adopted or may
have diminished with time. The availability of new technical
information and methods justify a review and modification of existing
requirements.
The NRC solicited comments from industry on specific regulatory
requirements and associated regulatory positions that needed
reevaluation. The Atomic Industrial Forum conducted a survey providing
most of industry's input, published for the NRC as NUREG/CR-4330
1, ``Review of Light Water Reactor Regulatory Requirements,'' Vol.
1, April 1986. A list of 45 candidates for potential regulatory
modification were identified. The NRC's review of the list selected
Appendix J as one of seven areas requiring further analysis (NUREG/CR-
4330, Vols. 2 and 3, dated June 1986 and May 1987). The NRC also
conducted a survey of its staff on the same issue. The NRC staff survey
identified 54 candidates for regulatory modification, a number of which
were previously identified in the industry survey. The NRC's assessment
of this list also selected Appendix J as a potential candidate for
modification.
\1\ Copies of NUREGs may be purchased from the Superintendent of
Documents, U.S. Government Printing Office, P. O. Box 37082,
Washington, DC 20013-7082. Copies are also available from the
National Technical Information Service, 5285 Port Royal Road,
Springfield, VA 22161. A copy is available for inspection and/or
copying in the NRC Public Document Room, 2120 L Street, NW. (Lower
Level), Washington, DC.
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The NRC published in the Federal Register, for comment, a proposed
revision to Appendix J on October 29, 1986 (51 FR 39538) to update
acceptance criteria and test methods based on experience in applying
the existing requirements and advances in containment leak testing
methods, to resolve interpretive questions, and to reduce the number of
exemption requests. This proposed rule was withdrawn from further
consideration and superseded with a more comprehensive revision of
Appendix J.
The NRC published a notice in the Federal Register on February 4,
1992 (57 FR 4166), presenting its conclusion that Appendix J was a
candidate whose requirements may be relaxed or eliminated based on
cost-benefit considerations. On the basis of NRC staff analyses of
public comments on the proposal, the Commission approved and announced
on November 24, 1992 (57 FR 55156) its plans to initiate rulemaking for
developing a performance-oriented and risk-based regulation for
containment leakage-testing requirements. On January 27, 1993, (58 FR
6196) the NRC staff published a general framework for developing
performance-oriented and risk-based regulations and, at a public
workshop on April 27 and 28, 1993, invited discussions of specific
proposals for modifying containment leakage-testing requirements.
Industry and public comments on the proposals, and other
recommendations and innovative ideas raised at the public workshop,
were documented in the proceedings of the workshop (NUREG/CP-0129,
September 1993). Specifically, the NRC concluded that the allowable
containment leakage rate utilized in containment testing may be
increased and other Appendix J requirements need not be as prescriptive
as the current requirements. To increase flexibility, the detailed and
prescriptive technical requirements contained in Appendix J regulations
could be improved and replaced with performance-based requirements and
supporting regulatory guides. The regulatory guides would allow
alternative approaches, although compliance with existing regulatory
requirements would continue to be acceptable. The performance-based
requirements would reward superior operating practices.
The present rulemaking is part of this overall effort and
initiative for eliminating requirements that are marginal to safety and
is guided by the policies, framework and criteria for the
[[Page 49496]]
program. A more comprehensive proposed rule than that proposed in 1986
that accounts for the latest technical information and regulatory
framework, using performance-oriented and risk-based approaches, was
published by the NRC in the Federal Register on February 21, 1995. The
public comment period for the proposed rule closed May 8, 1995.
NRC's Regulatory Improvement Program
The NRC's marginal-to-safety initiative is part of a broader NRC
initiative for regulatory improvement. Through its Program for
Regulatory Improvement, the NRC has institutionalized an ongoing effort
to eliminate requirements marginal to safety and to reduce the
regulatory burden on its licensees. The NRC staff's plan, summarized in
SECY-94-090, dated March 31, 1994, satisfies the requirement for a
periodic review of existing regulations given in Executive Order 12866
of September 30, 1993. This plan was approved by the Commission on May
18, 1994. The Regulatory Improvement Program is aimed at the
fundamental principle adopted by the Commission that all regulatory
burdens must be justified and that its regulatory process must be
efficient. In practice, this means the elimination or modification of
requirements for which burdens are not commensurate with their safety
significance. The activities of the Regulatory Improvement Program
should result in enhanced regulatory focus in areas that are more
safety significant. As a result, an overall net increase in safety is
expected from the program.
The Regulatory Improvement Program will include, whenever feasible
and appropriate, the consideration of performance-oriented and risk-
based approaches. The program will review requirements or license
conditions that are identified as a significant burden on licensees. If
review and analysis find that the requirements are marginal to safety,
they will be eliminated or relaxed. By performance-oriented, the NRC
means establishing regulatory objectives without prescribing the
methods or hardware necessary to accomplish the objective, and allowing
licensees the flexibility to propose cost-effective methods for
implementation. By risk-based, the NRC means regulatory approaches that
use probabilistic risk analysis (PRA) as the systematic framework for
developing or modifying requirements.
In institutionalizing the Regulatory Improvement Program and
adopting a performance-based regulatory approach, the NRC has
formulated the following framework for revisions to its regulations:
(1) The new performance-based regulation will be less prescriptive
and will allow licensees the flexibility to adopt cost-effective
methods for implementing the safety objectives of the original rule.
(2) The regulatory safety objectives will be derived, to the extent
feasible and practical, from risk considerations with appropriate
consideration of uncertainties, and will be consistent with the NRC's
Safety Goals.
(3) Detailed technical methods for measuring or judging the
acceptability of a licensee's performance relative to the regulatory
safety objectives will be, to the extent practical, provided in
industry standards and guidance documents which are endorsed in NRC
regulatory guides.
(4) The new regulation will be optional for current licensees so
that licensees can decide to remain in compliance with current
regulations.
(5) The regulation will be supported by necessary modifications to,
or development of, the full body of regulatory practice including, for
example, standard review plans, inspection procedures, guides, and
other regulatory documents.
(6) The new regulation will be formulated to provide incentives for
innovations leading to improvements in safety through better design,
construction, operating, or maintenance practices.
Current Appendix J Requirements
Appendix J to 10 CFR Part 50, ``Primary Reactor Containment Leakage
Testing for Water-Cooled Power Reactors,'' became effective on March
16, 1973. The regulatory safety objective of reactor containment design
is stated in 10 CFR Part 50, Appendix A, ``General Design Criteria for
Nuclear Power Plants,'' Criterion No. 16, ``Containment Design.'' GDC
Criterion 16 mandates ``an essentially leak-tight barrier against the
uncontrolled release of radioactivity to the environment * * *'' for
postulated accidents. Appendix J to 10 CFR Part 50 implements, in part,
General Design Criterion No. 16 and specifies containment leakage-
testing requirements, including the types of tests required. For each
type of test required, Appendix J specifies how the tests should be
conducted, the frequency of testing, and reporting requirements.
Appendix J requires the following types of containment leak tests:
(1) Measurement of the containment integrated leakage rate (Type A
tests, often referred to as ILRTs).
(2) Measurement of the leakage rate across each pressure-containing
or leakage-limiting boundary for various primary reactor containment
penetrations (Type B tests).
(3) Measurement of the containment isolation valves leakage rates
(Type C tests).
Type B and C tests are referred to as local leakage-rate tests
(LLRTs).
Leak-Tightness Requirements
Compliance with 10 CFR Part 50, Appendix J, requirements is
determined by comparing the measured containment leakage rate with the
maximum allowable leakage rate. Maximum allowable leakage rates are
calculated in accordance with 10 CFR Part 100, ``Reactor Site
Criteria,'' and are incorporated into the technical specifications.
Typical allowable leakage rates are 0.1 percent of containment volume
per day for pressurized water reactors (PWRs) and one volume percent
per day for boiling water reactors (BWRs).
Test Frequency Requirements
Schedules for conducting containment leakage-rate tests are
specified in Appendix J for both preoperational and periodic tests.
Periodic leakage-rate test schedules are as follows:
Type A Tests
(1) After the preoperational leakage-rate test, a set of three Type
A tests must be performed at approximately equal intervals during each
10-year service period. The third test of each set must be conducted
when the plant is shut down for the 10-year plant in-service
inspection.
(2) The performance of Type A tests must be limited to periods when
the plant facility is nonoperational and secured in the shutdown
condition under administrative control and in accordance with the
safety procedures defined in the license.
(3) If any periodic Type A test fails to meet the applicable
acceptance criteria, the test schedule applicable to subsequent Type A
tests will be reviewed and approved by the Commission. If two
consecutive periodic Type A tests fail to meet the applicable
acceptance criteria, a Type A test must be performed at each plant
shutdown for refueling or approximately every 18 months, whichever
occurs first, until two consecutive Type A tests meet the
[[Page 49497]]
acceptance criteria, after which time the regular retest schedule may
be resumed.
Type B Tests
(1) Except for airlocks, Type B tests must be performed during
reactor shutdown for refueling, or other convenient intervals, but in
no case at intervals greater than 2 years. If opened following a Type A
or B test, containment penetrations subject to Type B testing must be
tested prior to returning the reactor to an operating mode requiring
containment integrity. For primary reactor containment penetrations
employing a continuous leakage monitoring system, Type B tests, except
for tests of airlocks, may be performed at every other reactor shutdown
for refueling but in no case at intervals greater than 3 years.
(2) Airlocks must be tested prior to initial fuel loading and at
six-month intervals thereafter. Airlocks opened during periods when
containment integrity is not required by the plant's technical
specifications must be tested at the end of such periods. Airlocks
opened during periods when containment integrity is required by the
plant's technical specifications must be tested within 3 days after
being opened. For airlock doors opened more frequently than once every
3 days, the airlock must be tested at least once every 3 days during
the period of frequent openings. For airlock doors having testable
seals, testing the seals fulfills the 3-day test requirement. Airlock
door-seal testing must not be substituted for the 6-month test of the
entire airlock at not less than Pa, the calculated peak
containment pressure related to the design basis accident.
Type C Tests
Type C tests must be performed during each reactor shutdown for
refueling, but in no case at intervals greater than 2 years.
There have been two amendments to this Appendix since 1973. The
first amendment, published September 22, 1980 (45 FR 62789), modified
the Type B penetration test requirements to conform to what had become
accepted practice through the granting of exemptions. The second
amendment, published November 15, 1988 (53 FR 45890), incorporated the
Mass Point Statistical Analysis Technique as a permissible alternative
to the Total Time and Point-to-Point techniques specified in Appendix
J.
International Experience
A combination of Type A tests and an on-line monitoring (OLM)
capability is being actively pursued in Canada and Europe, notably in
France and Belgium, and is currently being considered in Sweden. OLM is
used to identify a ``normal'' containment pressurization pattern and to
detect deviations from that pattern. With on-line, low-pressure
testing, Hydro-Quebec's Gentilly-2 station is able to monitor the
change in containment leaktightness between Type A tests. The Belgians
conduct a leakage test using OLM during reactor operation after each
cold shutdown longer than 15 days with the objective of detecting gross
leaks. The objective of the Belgian approach to Type A testing is to
reduce the frequency and duration of the tests. The Type A test is
conducted at a containment pressure (Pt) not less than half of the
peak pressure (0.5 Pa). It is performed once every 10 years. In
France, containment leaktightness is continuously monitored during
reactor operation in all of the French PWR plants using the SEXTEN
system. It is also being evaluated by the Swedes for their PWR units.
Leaks may be detected during the positive or negative pressure periods
in the containment by evaluating the air mass balance in the
containment. Type A tests are conducted at containment peak pressure
(loss-of-coolant accident pressure) before initial plant startup,
during the first refueling, and thereafter every 10 years unless a
degradation in containment leaktightness is detected. In that case,
tests are conducted more frequently.
Further details of international approaches to containment testing
are provided in NUREG-1493.
Advance Notices for Rulemaking
Over time, it has become apparent that variations in plant design
and operation frequently make it difficult to meet some of the
requirements contained in Appendix J because of its prescriptive
nature. Economic and occupational exposure costs are directly related
to the frequency of containment testing. Containment integrated
leakage-rate tests (Type A) preclude any other reactor maintenance
activities and thus are on the critical path for return to service from
reactor outages. In addition to the costs of the tests, integrated leak
tests impose the added burden of the cost of replacement power.
Containment-penetration leak tests (Type B and C) can be conducted
during reactor shutdowns in parallel with other activities and thus
tend to be less costly; however, the large number of penetrations
impose a significant burden on the utilities. Additionally, risk
assessments performed to date indicate that the allowable leakage rate
from containments can be increased, and that control of containment
leakage at the current low rates is not as risk significant as
previously assumed.2 3
\2\ ``Severe Accident Risks: An assessment for five U. S.
Nuclear Power Plants, Final Summary Report.'' NUREG-1150, December
1990. Copies of NUREGs may be purchased from the Superintendent of
Documents, U.S. Government Printing Office, P. O. Box 37082,
Washington, DC 20013/7082. Copies are also available from the
National Technical Information Service, 5285 Port Royal Road,
Springfield, VA 22161. A copy is available for inspection and/or
copying in the NRC Public Document Room, 2120 L Street, NW. (Lower
Level), Washington, DC.
\3\ ``Performance-Based Containment Leak Test Program,'' NUREG-
1493, July 1995.
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In August of 1992, the NRC initiated a rulemaking to modify
Appendix J to make it less prescriptive and more performance-oriented.
The Commission also initiated a plan to relax the allowable containment
leakage rate used to define performance standards for containment
tests. In the Federal Register of January 27, 1993 (58 FR 6196), the
NRC indicated the following potential modifications to Appendix J of 10
CFR Part 50 would be considered:
(1) Increase allowable containment leakage rates based on Safety
Goals and PRA technology (i.e., define a new performance standard); and
(2) Modify Appendix J to be a performance-based regulation:
A. Limit the revised rule to a new regulatory objective. In order
to ensure the availability of the containment during postulated
accidents, licensees should either:
(i) Test overall containment leakage at intervals not longer than
every 10 years, and test pressure-containing or leakage-limiting
boundaries and containment isolation valves on an interval based on the
performance history of the equipment; or
(ii) Provide on-line (i.e., continuous) monitoring of containment
isolation status.
B. Remove prescriptive requirements from Appendix J and preserve
useful portions as guidance in an NRC regulatory guide.
C. Endorse industry standards on:
(i) Guidance for calculating plant-specific allowable leakage rates
based on new NRC performance standards;
(ii) Guidance on the conduct of containment tests; and
(iii) Guidance for on-line monitoring of containment isolation
status.
D. Continue to accept compliance with the current detailed
requirements in Appendix J (i.e., licensees presently in compliance
with Appendix J will not need to do anything if they do not wish to
change their practice).
[[Page 49498]]
A public workshop on the subject was held by the NRC on April 27
and 28, 1993.4
\4\ ``Workshop on Program for Elimination of Requirements
Marginal to Safety,'' NUREG/CP-0129, September 1994.
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February 1995 Proposed Revision
Based on several advance notices for rulemaking and significant
public comment and discussion, evaluation of risks and costs, and
consideration of which modifications have become feasible and
practical, in the February 21, 1995, Federal Register the NRC proposed
two phases for modifications of requirements to containment leakage
testing. The first phase allowed leakage-rate testing intervals to be
based on the performance of the containment system structures and
components. The second phase will further examine the needed
requirements of the containment function (i.e. structural and leak-
tight integrity of containment system structures and components, and
prevention of inadvertent bypass), and include consideration of the
potential for on-line monitoring of containment integrity to verify
certain functions. Public comments were solicited to guide this future
work.
The February 21, 1995, proposed rule applies to all NRC licensees
who operate light-water-cooled power reactors. The proposed rule allows
licensees the option of continuing to comply with the current Appendix
J or to adopt the new performance-based standards.
The NRC's analyses are based upon the insight gained through the
use of probabilistic risk assessment techniques and the significant
data base of practical, hands-on operating experience gained since
Appendix J was promulgated in 1973. This operating experience provides
solid evidence of the activities necessary to conduct Appendix J
testing, and the costs of those activities both in monetary terms and
occupational radiation exposure.
The proposed rule is based on analytical efforts documented in
NUREG-1493 which, like NUREG-1150, confirms previous observations of
insensitivity of population risks from severe reactor accidents to
containment leakage rates.
The current Appendix J requirements continue to achieve the
regulatory criterion of assuring an essentially leak-tight boundary
between the power reactor system and the external environment (General
Design Criterion 16). Costs associated with complying with current
Appendix J requirements are estimated to be $165,000 for a complete
battery of Type B/C tests and $1,890,000 for Type A tests. Over the
average reactor's remaining lifetime of 20 years, the present value of
all remaining containment leakage testing at a 5 percent discount rate
is estimated to be about $7 million per reactor. Estimates of the
remaining industry-wide costs of implementing current Appendix J
requirements ranged from $720 to $1,080 million, approximately 75
percent of which could be averted with a performance-based rule.
The Regulatory Analysis for the proposed rule finds that by
allowing requirements to remain in effect with marginal impact on
safety, but which impose a significant cost on licensees, is to have
missed an opportunity to improve regulatory coherence and to focus
NRC's regulations to areas where the return in terms of added public
safety is higher.
Specific alternatives for modifying the current Appendix J were
identified by the public in response to the NRC's Federal Register
notice published on January 27, 1993 (58 FR 6196). Those whose
characteristics matched the NRC's established criteria for the marginal
to safety program were selected for further review.
Modifications of Advance NRC Proposal
Allowable Leakage Rate
The NRC had initially planned to establish, by rulemaking, a risk-
based allowable leakage rate commensurate with its significance to
total public risk. Specific findings from NUREG-1493 on the allowable
leakage rate include:
1. Allowable leakage could be increased approximately two orders of
magnitude (100-200 fold) with marginal impact on population dose
estimates from reactor accidents.
2. Calculated risks to individuals are several orders of magnitude
below the NRC's Safety Goals for all reactors considered.
3. Increases in the allowable leakage rate are estimated to have a
negligible impact on occupational exposure.
Relaxing the allowable leakage rate is estimated to reduce future
industry testing costs by $50 to $110 million, a 10 percent decrease in
overall leakage-rate testing costs.
A risk-based allowable leakage rate would be based on an
evaluation, using PRA, of the sensitivity and significance of
containment leakage to risk, and the determination of an appropriate
containment leakage limit commensurate with its significance to the
risk to the public and plant control-room operators. However, this
would have entailed a major change in policy and restructuring of the
current licensing basis and a more complete understanding of the
uncertainties associated with the threat of severe accidents to the
containment, and therefore, the NRC planned to develop a modification
of the performance standard (allowable leakage level) in the second
phase separate from modifications of testing requirements. This
modification would be part of a broader effort to further examine the
risk significance of various attributes of containment performance,
i.e., structural and leak-tight integrity of containment-system
structures and components, and inadvertent bypass.
On-Line Monitoring (OLM) Systems
Currently, there is no NRC requirement for systems which
continuously monitor the containment to detect unintentional breaches
of containment integrity.
Studies discussed in NUREG-1493, ``Performance-Based Containment
Leak Test Program,'' found that, based on operating experience, OLM
would not significantly reduce the risk to the public from nuclear
plant operation and, thus, could not be justified solely on the basis
of risk-based considerations. Specific findings include:
1. Existing continuous monitoring methods appear technically
capable of detecting leaks in reactor containments within 1 day to
several weeks. OLM systems are in use or planned in several European
countries and Canada.
2. OLM systems are capable of detecting leaks only in systems that
are open to the containment atmosphere during normal operation
(approximately 10 percent of the mechanical penetrations).
3. The technical and administrative objectives of OLM systems and
Type A tests are different.
4. OLM could not be considered as a complete replacement for Type A
tests because it cannot challenge the structural and leak-tight
integrity of the containment system at elevated pressures.
5. Analysis of the history of operating experience indicated a
limited need for, and benefit of, OLM in the U.S.
Although OLM can not be justified solely based on risk
considerations, a plant already possessing such a system has a greater
assurance of achieving certain attributes of containment integrity.
Therefore, OLM systems could contribute towards an overall leakage-
monitoring scheme. Some capability for on-line monitoring already
exists as a byproduct of specific containment designs. For example,
licensees with
[[Page 49499]]
inerted BWR containments, or subatmospheric PWR containments, could
possibly detect gross leakages that develop during normal operation.
Given that the application of on-line monitoring is specific to
containment design, and generic application can not be justified solely
on risk considerations, the NRC did not propose a requirement for OLMs.
However, licensees with such a capability (e.g. inerted BWR
containments, and subatmospheric PWR containments) were encouraged to
propose plant-specific application of such a capability, and to take
credit for any added assurance of containment integrity provided by
such a system compared to other testing methods. The NRC proposed to
reconsider the role of OLM in the second phase of modifications in this
area along with the allowable leakage rate.
Proposed Modification of Type A, B, and C Test Intervals
In the February 1995 proposed rule, the NRC proposed a new risk-
based regulation based on the performance history of components
(containment, penetrations, valves) as the means to justify an increase
in the interval for Type A, B, and C tests. The revised regulation
requires tests to be conducted on an interval based on the performance
of the containment structure, penetrations and valves without
specifying the interval in the regulation. Currently, three Type A
tests are conducted in every 10 year period. Type B (except airlocks,
which are tested more frequently) and C tests are conducted on a
frequency not to exceed 2 years.
The NRC proposed to base the frequency of Type A tests (ILRTs) on
the historical performance of the overall containment system. Specific
findings documented in NUREG-1493 that justify the proposal include:
1. The fraction of leakages detected only by ILRTs is small, on the
order of a few percent.
2. Reducing the frequency of ILRT testing from 3 every 10 years to
1 every 10 years leads to a marginal increase in risk.
3. ILRTs also test the strength of the containment structure. No
alternative to ILRTs has been identified to provide assurance that the
containment structure would meet allowable leakage rates during design-
basis accidents.
4. At a frequency of 1 test every 10 years, industry-wide
occupational exposure would be reduced by 0.087 person-sievert (8.7
person-rem) per year.
Based on specific, detailed analyses of data from the North Anna
and Grand Gulf nuclear power plants, and data from twenty-two nuclear
plants (see NUREG-1493), performance-based alternatives to current LLRT
methods are feasible with marginal impact on risk. Specific findings
include:
1. Type B and C tests are capable of detecting over 97 percent of
containment leakages.
2. Of the 97 percent, virtually all leakages are identified by
LLRTs of containment isolation valves (Type C tests).
3. Based on the detailed evaluation of the experience of a single
two-unit station, no correlation of failures with type of valve or
plant service could be found.
4. For the 20 years of remaining operations, changing the Type B/C
test frequency to once every 5 years for good-performing components is
estimated to reduce industry-wide occupational radiation exposure by
0.72 person-sievert (72 person-rem) per year. If 20-year license
extension is assumed, the estimate is 0.75 person-sievert (75 person-
rem) per year.
Future industry testing costs are reduced by approximately $330 to
$660 million if ILRT tests are conducted once every 10 years rather
than the current 3 per 10 years. ILRT savings represent about 65
percent of the remaining costs of current Appendix J requirements.
Performance-based LLRT alternatives are estimated to reduce future
industry testing costs by $40 million to $55 million. LLRT savings
represent about 5 percent of the total remaining costs of Appendix J
testing.
Therefore, based on the risks and costs evaluated, and other
considerations discussed above, a performance-based Appendix J was
proposed which encompassed the following principles, which differ
moderately from those first described in the Federal Register (January
27, 1993 58 FR 6197).
General (1) Make Appendix J less prescriptive and more performance-
oriented; (2) Move details of Appendix J tests to a regulatory guide as
guidance; (3) Endorse in a regulatory guide the industry guideline (NEI
94-01) on the conduct of containment tests (The methods for testing are
contained in an industry standard (ANSI/ANS 56.8-1994) which is
referenced in the NEI guideline); and (4) Allow voluntary adoption of
the new regulation, i.e., current detailed requirements in Appendix J
will continue to be acceptable for compliance with the modified rule.
Leakage Limits Acknowledge the less risk-significant nature of
allowable containment leakage but pursue its modification as a separate
action.
Type A Test Interval (1) Based on the limited value of integrated
leakage-rate tests (ILRTs) in detecting significant leakages from
penetrations and isolation valves, establish the test interval based on
the performance of the containment system structure; (2) The
performance criterion of the test will continue to be the allowable
leakage rate (La); (3) The industry guideline allows extension of the
Type A test interval to once every 10 years based on satisfactory
performance of two previous tests, inclusive of the pre-operational
ILRT; (4) In the regulatory guide, the NRC takes exception to industry
guidance for the extension of the interval of the general visual
inspection of the containment system, and limits the interval to 3
times every 10 years, in accordance with current practice.
Type B & C Test Interval (1) Allow local leakage-rate test (LLRTs)
intervals to be established based on the performance history of each
component; (2) The performance criterion for the tests will continue to
be the allowable leakage rate (La); (3) Specific performance factors
for establishing extended test intervals (up to 10 years for Type B
components, and 5 years for Type C components) are contained in the
regulatory guide and industry guideline. In the regulatory guide, the
NRC has taken exception to the NEI guideline allowing the extension of
Type C test intervals up to 10 years, and limits such extensions to 5
years.
Summary of Public Comments
Twenty-six letters were received that addressed the policy,
technical, and cost aspects of the proposed rulemaking, including the
nine questions posed by the NRC in the February 21, 1995 proposed rule.
All comments, including the ones received by the NRC after the deadline
were considered. The commenters included 4 private citizens, 1 public
interest group, 18 utilities, 1 nuclear utility industry group, 1 State
regulatory agency, and 1 foreign regulator.
Although the proposed rule did not generate a significant number of
public comments, the commenters did align themselves into two distinct
groups: those who supported publishing the rule and those against.
Those who supported publishing the rule comprise the vast majority of
the commenters (22) and included the Nuclear Energy Institute (NEI),
which represents the nuclear utility licensees, eighteen individual
nuclear power plant licensee respondents, a Spanish regulatory
authority and two private citizens (Mr.
[[Page 49500]]
Hill and Mr. Barkley). This group is very supportive of the
Commission's risk-based regulatory program, and supports proceeding
with the rule in an expeditious manner, despite having reservations
about three specific provisions. The issues of most concern to this
group are: (1) Licensee commitments to certain requirements of the
regulatory guide implementing Appendix J testing via use of the
technical specifications (industry would prefer using a plant's final
safety analysis report); (2) requirements to conduct visual internal
and external inspections of the containment on a frequency of 3 times
per 10 years (industry would prefer once per 10 years to coincide with
Type A tests); (3) making Option B of the proposed rule mandatory
(industry would prefer to retain the optional feature); and (4) Type C
test frequency (industry would prefer a 10-year test interval for
certain Type C valves). Industry supports a future rulemaking to
increase the allowable leakage rate.
Two private citizens (Mr. Arndt and Dr. Reytblatt) are opposed to
the proposed rule. The issues of most concern to these citizens are:
(1) Type A test frequency (Mr. Arndt would prefer that frequencies be
held at current levels); (2) Type A test methodology (Dr. Reytblatt
wants to halt Type A testing until the test accuracy is improved); (3)
Type C test frequencies (Mr. Arndt believes the existing database does
not support 10-year test intervals, and suggests 5-years as an upper
limit at the present time); and (4) Leakage rate (a future rulemaking
to increase the allowable leakage rate should not be undertaken).
Two organizations are opposed to the proposed rule. The Bureau of
Nuclear Engineering of the state of New Jersey and the Ohio Citizens
for Responsible Energy (OCRE, represented by Ms. Hiatt), a public
interest group, expressed skepticism in the risk-based approach to
regulation as embodied in the philosophy of the Marginal-to-Safety
Program. The issues of most concern to this group are that: (1)
Increases in public risk are not acceptable, no matter how marginal;
and (2) A future rulemaking to increase the allowable leakage rate
should not be undertaken.
NRC Position. With respect to the areas of disagreement between the
NRC and those who generally support the proposed rule, no new
information has been provided in the public comments that was not
already addressed in ongoing dialogue. Accordingly, the NRC has not
made any substantive changes to its proposed regulation. Specifically,
the NRC has retained: (1) Its position of requiring the use of
technical specifications; (2) The intervals established for visual
examinations of containment; and (3) The 5-year Type C test interval.
With respect to the optional feature of the rule, the NRC agrees
with the industry and has retained this feature. With respect to Mr.
Arndt and Dr. Reytblatt, the NRC agrees in part with Mr. Arndt and has
decided not to alter the LLRT test interval as noted in item (3). The
other issues raised by Mr. Arndt and Dr. Reytblatt contain no
information that has not been considered previously in a public forum.
Therefore, the NRC has decided to make no substantive changes to its
proposed rule as a result of the issues raised. With respect to the two
organizations opposed to the proposed rule (OCRE and the NJ Bureau of
Nuclear Engineering), neither has provided new information or a
compelling reason to abandon the risk-based approach to regulation.
In its preliminary criteria for developing performance-based
regulations, the NRC identified several issues to be addressed by the
rulemaking process as a measure of the viability of the revised rule.
These issues were addressed in the proposed rule and the NRC sought
further public input on them. Comments were received on these topics in
addition to other areas of interest to the public. The following is a
summary of comments received on these issues and areas, and NRC's
response. A complete discussion of all comments is included in the
Public Comment Resolution Document.5
\5\ Copies are available for inspection or copying for a fee
from the NRC Public Document Room at 2120 L Street NW., Washington,
DC; the PDR's mailing address is Mail Stop LL-6, Washington, DC
20555; telephone (202) 634-3273; fax (202) 634-3343.
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1. Can the new rule and its implementation yield an equivalent
level of, or would it only have a marginal impact on safety?
Twenty-four commenters addressed this issue, offering a wide
variety of opinions. Twenty commenters believe that implementation of
the proposed rule will provide an equivalent level of safety to that
provided by the current rule. A majority of commenters, representing
for the most part nuclear utilities, believe that the proposed
regulation will reduce the testing burden currently imposed on the
nuclear industry, and will result in more efficient use of utility
resources, while ensuring the health and safety of the public. They
believe that the practical experience gained from more than 1,500
reactor-years of commercial nuclear power-plant operation provides an
appropriate basis to adjust the Appendix J testing intervals which were
established over 20 years ago on the basis of engineering judgment.
Further, these commenters believe that a significant reduction in
occupational exposures can be achieved with reduced testing frequency.
Mr. E. Gunter Arndt, a private citizen, believes that the NRC has
neither sufficient objective data nor perspective to justify increasing
containment leakage rates, decreasing test frequencies, relaxing
testing criteria, and reducing containment-system maintenance
standards. Dr. Reytblatt, a private citizen, believes that Type A
testing must be immediately suspended because the current testing
methodology is flawed. Mr. Kent W. Tosch, Manager of New Jersey's
Bureau of Nuclear Engineering, points out that the containment is an
extremely important barrier to a release of radioactivity, but the
philosophy reflected in this rulemaking is that this barrier can be
allowed to become less reliable, even when some nuclear plants are
showing signs of aging. Ms. Susan L. Hiatt, Director of Ohio Citizens
for Responsible Energy, notes that relaxing the frequency of Appendix J
tests leads to an increase in overall reactor risk of approximately 2
percent and, while the NRC may deem this to be marginal, it nonetheless
is an increase in risk.
The NRC believes it has collected sufficient subjective and
independent data to conduct its risk analysis. Detailed data from two
independent power plants, representing four units, data supplied by the
NEI representing approximately 30 additional units, and approximately
180 ILRT and licensee event reports were analyzed. These data produced
consistent results. Dr. Reytblatt's views, while technically correct,
have been opposed by several technically competent organizations
including the American National Standards Institute, and Oak Ridge
National Laboratory because the improvements he suggests will have an
insignificant effect on measured containment leakage rates in practice
and thus have no safety significance. The NRC believes there has been
ample opportunity for public discussion of the basis for the Appendix J
revisions.
Based on the foregoing, the NRC reaffirms its prior conclusion
(stated in the February 21, 1995, Federal Register notice) that its
safety objective for containment integrity can be maintained while at
the same time reducing the burden on licensees. Additionally, the final
rule provides a greater level of worker safety than that provided by
the previous rule.
[[Page 49501]]
2. Can the regulatory/safety objective (qualitative or
quantitative) be established in an objective manner to allow a common
understanding between licensees and the NRC on how the performance or
results will be measured or judged?
To avoid repetition, the NRC incorporated responses to this
question with those of Question 3.
3. Can the regulation and implementation documents be developed in
such a manner that they can be objectively and consistently inspected
and enforced against?
Approximately 20 commenters expressed opinions on Questions #2 and
#3. The majority of the commenters believe that regulatory/safety
objectives can be established objectively, and can be consistently
enforced, although opinions differ on the optimum enforcement
mechanism. Mr. Fernando Robledo of the Spanish nuclear regulatory
agency states that the use of probabilistic risk assessment in the
regulatory process provides a more realistic and objective assessment
of nuclear safety, and thus supports its increased use in the
regulatory process. The NEI believes the use of technical
specifications for inspection and enforcement is neither necessary nor
warranted and that, rather than a licensee commitment in the plant
technical specification, future licensee commitments to implement
Option B should be provided by documentation in the updated Final
Safety Analysis Report.
To assist in the common understanding of new methods of
establishing Type A, B, and C test frequencies between the NRC and
power reactor licensees, the NRC has had ongoing discussions with
licensees. These discussions included participation in workshops
designed to elicit a common understanding. Also, the NRC wishes to
retain the current practice which requires its review and approval of
changes to Appendix J performance limits and surveillance requirements.
Therefore, the NRC has required that the regulatory guide should be
specified in the technical specifications, an approach not inconsistent
with the Commission's policy on technical specifications.
Based on the foregoing, the NRC reaffirms its prior conclusion
(stated in the February 21, 1995, proposed rule) that it expects that
its activities to date, the review and endorsement of a industry
guideline in a regulatory guide, and the general reference of the
regulatory guide in plant technical specifications, will provide a
common understanding on the measures of compliance.
4. Should the proposed revision be made even less prescriptive?
Except for Mr. Hill and Mr. Barkley, commenters did not explicitly
address this question, which was directed at the possibility of
reducing, even further, the testing frequency of ILRTs based on the
fact that there does seem to be a strong statistical link between
passing or failing successive ILRTs. Mr. Hill believes that there is no
need to make the rule less prescriptive, and it may be inferred that is
no desire on the part of industry to further increase the testing
interval between ILRTs or to eliminate them completely. Richard
Barkley, although strongly supporting an adjustment to the frequency of
Type A testing to once every 10 years, also discourages the NRC from
adopting a Type A surveillance interval any longer than 10 years
because of aging considerations.
The NRC has decided, in general, to maintain the present level of
prescriptiveness in the proposed rule and, in particular, to not
decrease further the test frequency for ILRTs. The NRC's position is
guided by the desire to maintain some conservatism to address
uncertainties and adopt an evolutionary approach wherein incentives
remain for good performance.
5. Should the proposed revisions be made mandatory?
To avoid repetition, the NRC incorporated responses to this
question with those of Question 7.
6. Was the definition of ``backfit'' in Sec. 50.109(a)(1) intended
to encompass rulemakings of the type represented by this proposed rule?
To avoid repetition, the NRC incorporated responses to this
question with those of Question 7.
7. Is it appropriate for the Commission to waive the applicability
of the Backfit Rule?
The majority of the 20 commenters believe that compliance with the
performance-based Appendix J program should not be made mandatory. The
NEI believes that rulemakings that provide relief from a current
regulation but would also contain one or more new requirements (as is
the case here) would be subject to the backfit rule. These commenters
believe that application of the backfit rule would be necessary before
the NRC could promulgate the performance-based Appendix J program as a
requirement, believing some licensees might select, for reasons of
cost, to continue to comply with the existing Appendix J.
The majority of commenters believe that the backfit rule would
apply and should not be waived. Several utilities have no objection to
waiving a backfit analysis when clear relief is available, but are
concerned with the generic implications of waiving the applicability of
the backfit rule. The NEI believes that while the proposed Appendix J
revisions would provide much needed performance-based improvements to
the existing Appendix J, it would also impose new requirements; thus,
the proposed rule constitutes a backfit. Further, this commenter
believes that, as a matter of administrative law, an agency lacks
authority to depart from its own rules, thus, it cannot waive its own
regulations.
The NRC believes that if the rule were made mandatory, all
licensees would incur costs setting up the procedures for implementing
the rule's requirements following the guidance provided in the
regulatory guide and the NEI guidance document. For those utilities
whose circumstances (e.g., remaining plant life) would lead them to
follow the current Appendix J, costs would be incurred with no
additional benefit. Thus, the NRC agrees with the opinions expressed by
the NEI and has decided to retain the proposed rule in its present
form, which provides a non-mandatory alternative to the current
Appendix J requirements. Because the NRC has decided to retain the
optional feature of the proposed rule, the question of backfit is not
addressed.
8. Should NRC pursue a fundamental modification of its regulations
in this area by establishing an allowable leakage rate based on risk
analysis (as presented in draft NUREG-1493, Chapter 5), as compared to
the current practice of using deterministic design basis accidents and
dose guidelines contained in 10 CFR Part 100; or should the NRC modify
the allowable leakage rate within the current licensing basis by
revising source terms and updating regulatory guides (R.G.s 1.3 and
1.4) 6 for calculating doses to the public? What are the
advantages and disadvantages of the two approaches? What are some other
considerations than risk to public, e.g., plant control room
habitability, that might limit the allowable leakage rate?
\6\ Copies may be purchased at current rates from the
Superintendent of Documents, U.S. Government Printing Office, P.O.
Box 37082, Washington, DC 20402-9328 (telephone 202-512-2249 or 202-
512-2171); or from the National Technical Information Service by
writing NTIS at Port Royal Road, Springfield, VA 22161.
---------------------------------------------------------------------------
The 20 commenters who responded to this question consist
predominantly of the utilities endorsing the NEI position. These
respondents encourages the NRC
[[Page 49502]]
to pursue a rulemaking to alter allowable leakage rates using risk-
based analysis, believing that a firm technical basis exists for
relaxing leakage rates up to two orders of magnitude with only a
marginal impact on population risk estimates. It was also suggested
that a review of the present source terms, dose projection models, and
associated assumptions against the revised source terms and dose
methodologies should also be performed to determine if relief can be
achieved while assuring public health and safety. Three commenters
discouraged the NRC from relaxing containment leakage rates ranging
from the opinion that little benefit would result (Mr. E. Gunter Arndt)
to an unequivocal belief that such a move would violate a plant's
licensing basis by eliminating the protection provided for the nearest
public individual by the 10 CFR Part 100 siting criteria (Ms. S.
Hiatt). Ms. Susan Hiatt, representing the Ohio Citizens for Responsible
Energy, believes that containment leak rates should be periodically
reexamined, not for the purpose of relaxing them, but to determine
whether they should be made more stringent given increasing population
density around operating nuclear power plants.
The NRC has decided to continue to pursue further reductions in
regulatory burden with marginal impacts on safety and will address the
complexities noted in the public comments in its future efforts to
relax the allowable leakage rate.
9. If the allowable leakage rate is increased, could on-line
monitoring of containment integrity replace other current containment
tests? Could the results of the on-line monitoring be used to establish
a new performance basis for containment integrity involving less
stringent reporting requirements if there is high assurance there are
no large leakage paths in containment (> 1 in. diameter).
The 18 commenters who responded to this question consist of the NEI
and the utilities endorsing the NEI position, and Mr. Richard Barkley.
The commenters do not believe that on-line monitoring (OLM) of
containment integrity can replace many of the current containment
tests, and state that OLM systems have very limited abilities to
identify breaches in containment integrity. In the experience of Mr.
Barkley, such systems add unnecessary plant complexity and cost.
The NRC acknowledges the public comments rendered and will be
guided by them in decisions yet to be made regarding the Phase 2
effort.
10. Are there any other regulatory approaches and technical methods
by which the NRC can adopt a complete performance and risk basis to its
regulations for containment leak-tight integrity? What are some of the
attributes for performance, and what risk-based methods can be used to
analyze these attributes?
The NEI, speaking for all other utilities, addressed this question
by stating that it had not conducted any analyses to determine whether
any other regulatory approaches and technical methods by which the NRC
can adopt a complete performance and risk basis to its regulations for
containment leak-tight integrity.
11. Rulemaking Documents.
Seventeen commenters expressed opinions about NRC's regulatory
policy decisions and/or specific language in the rule or its supporting
documents. Mr. Hill believes that the NRC's and the NEI's guidance
documents are not developed to the point of establishing a common
understanding of how to meet NRC's regulatory and safety objectives
(e.g., while NEI 94-01 contains a lot of information and solid
guidance, it also contains inconsistencies, contradictions and unclear
passages). The NEI, whose comments were endorsed by most responding
licensees, proposed modifications to several of the rulemaking
documents, including the Federal Register notice and its own guidance
document.
The NRC has amended its rule and accepts most of the revisions to
the implementing documents to clarify language and achieve consistency
between the rulemaking documents.
12. Technical Issues.
Testing Frequency
Twenty-four commenters expressed opinions on test frequency, the
majority were supportive of 10-year intervals for both Types A, B and C
tests. Regarding ILRTs, the Nuclear Energy Institute, several
individual utilities, and Mr. Howard Hill expressed views that the
proposed rule provides an acceptable testing frequency for ILRTs. Mr.
Fernando Robledo, of the Spanish nuclear regulatory agency, believes
that 10 years is too long a time interval between Type A containment
tests. Mr. E. Gunter Arndt's view is that a preoperational test should
not count as one of the two successful ILRT tests required to go to a
10-year test interval because preoperational conditions are not at all
representative of operating conditions. The citizens' group, Ohio
Citizens for Responsible Energy, believes the frequency of containment
leak-rate testing should remain unchanged from the current practice.
Several commenters also expressed opinions on the NRC's position on
LLRT testing frequency. Mr. Fernando Robledo, while agreeing in general
with the test frequency for type B and C tests proposed in the draft
regulatory guide, believes that certain mechanical penetrations
particularly important for plant safety should be leak tested every 24
months. Mr. E. Gunter Arndt's view is that the testing history of
penetrations, and especially of valves, does not support leaving them
untested for 10 years and suggested that an upper limit should be once
every 5 years. One utility in particular, and the Nuclear Energy
Institute in general believe that the NRC does not go far enough in
citing that several sets of data justify 10-year LLRT intervals. In
contrast, Mr. Richard Barkley, who also endorses Type B & C testing
frequency based on performance, strongly supports the NRC's proposal to
prohibit the adoption of Type C surveillance intervals longer than 60
months.
In establishing the 5-year test interval for LLRTs, the NRC has
designed a cautious, evolutionary approach as data are compiled to
minimize the uncertainty now believed to exist with respect to LLRT
data. The NRC's judgment, based on risk assessment and deterministic
analysis, continues to be that the limited database on unquantified
leakages and common mode and repetitive failures introduces significant
uncertainties into the probabilistic risk analysis. The NRC will be
open to submittals from licensees as more performance-based data are
developed. The extension of LLRT test interval to 5 years is a prudent
first step. By allowing a 25 percent margin in testing frequency
requirements, the NRC has provided the flexibility to accommodate
longer fuel cycles. With respect to the 10-year interval for ILRTs, the
NRC believes its technical support document (NUREG-1493) is persuasive
by demonstrating that testing intervals could be increased up to once
every 20 years with an imperceptible increase in risk, using actual
ILRT data which accounted for random and plant-specific failures and
plant aging effects.
Based on the foregoing discussion, the NRC has decided to retain
the 60-month Type C test interval and the 120-month interval for Type A
and B tests. In response to public comments, the NRC has revised the
regulatory guide to limit the extension of test intervals for main
steam and feedwater isolation valves in BWRs, and containment purge and
vent valves in PWRs and BWRs beyond 30 months given their operating
experience and/or safety significance.
[[Page 49503]]
Test Pressures
Two commenters expressed opinions on the magnitude of the pressures
used in conducting Type A leakage tests. Northern States Power Company
believes that Type A testing at full pressure is unnecessary and
believes that visual inspection coupled with a reduced pressure test
will adequately assure that the containment structural members are
leak-tight, especially since reduced pressure Type A tests are legally
acceptable tests as prescribed in the current 10 CFR Part 50, Appendix
J. Mr. E. Gunter Arndt states that while Type A tests performed at
reduced pressure rather than peak accident pressure are economically
advantageous to the industry, the results of these tests are not
necessarily indicative of leakage rates during accidents.
The NRC believes that extrapolating low pressure leakage-test
results to full pressure leakage-test results has turned out to be
unsuccessful. The NRC believes that the peak calculated accident
pressure: (1) Is consistent with the typical practice for NRC staff
evaluations of accident pressure for the first 24 hours in accordance
with Regulatory Guides 1.3 and 1.4; (2) Provides at least a nominal
check for gross leak paths which might exist at high test pressures,
but not at low test pressures; and (3) Directly represents technical
specification leakage-rate limits, and provides greater confidence in
containment system leak-tight integrity.
Based on the foregoing, the NRC has decided to retain the
calculated design basis loss-of-coolant accident peak pressure as the
ILRT test pressure.
Containment Inservice Visual Inspection
Eighteen commenters expressed opinions on this issue. The NEI and
most utilities oppose the NRC's proposal to require visual examination
of containment be performed 3 times every 10 years. These commenters
suggest that this issue be taken up in a parallel rulemaking.
The NRC finds the industry's arguments for relaxing the frequency
of containment visual inspections to be unpersuasive. Because the
visual examination is not integral to the ILRT (i.e., may be performed
independently) and because the NRC sees benefits to the early detection
of unknown aging mechanisms which may be active, the NRC considers it
prudent to conduct visual inspections on a frequency greater than the
ILRT. Further, the NRC believes it is inappropriate to defer a
requirement pertaining to containment structural integrity to an
ongoing rulemaking to incorporate ASME Section XI, IWE and IWL until
its form and substance is finalized.
Based on the foregoing, the NRC has decided to retain its frequency
for the inservice visual inspection.
Reporting Requirements
Only one comment was received on this issue. Dr. Z. Reytblatt noted
that the proposed rule's reporting requirements consist only of a cover
letter to the NRC and suggested this is intended to conceal information
from the public. Dr. Reytblatt suggests that utilities should be
required to submit all computer files related to testing to the NRC
immediately after the tests have been completed to prevent their
alteration or destruction.
It is not the intent of the NRC's reporting requirements to conceal
information from the public; if tests fail, the information is required
to be reported to the NRC, and the NRC will make such data available to
the public. The NRC has decided to retain its reporting requirements as
stated in the proposed rule.
Modifications to the Proposed Rule in Response to Public Comments
The NRC has decided to amend its proposed rule and its implementing
documents to clarify language. The NRC has concluded that its
regulatory analysis and its technical support document, NUREG-1493, do
not require corrections to its technical or cost analyses or its
findings. Modifications to all documents will be restricted to
clarifications and enhancements to assist in communications with the
reader, specifically in areas discussed in the public comments.
The proposed rule has been modified by changing ``Acceptance
criteria'' to ``Performance criteria'' in Section II, Definitions, and
various conforming text changes to reflect consistent use of that term.
Other similar redundant terms in the proposed rule, e.g. goals, have
been deleted to establish clear and concise language in the rule.
Specific changes to the draft regulatory guide, Section C,
Regulatory Position, include (1) in paragraph number 2, the inclusion
of the rationale for denying the ``3 refueling cycle'' change requested
in the public comments; (2) the inclusion of a new paragraph number 4,
taking exception to the NEI Industry Guideline, Section 10.2.3.3, which
provides guidance that an as-found Type C test or an alternative test
or analysis (emphasis added) shall be performed prior to any
maintenance, repair, modification, or adjustment activity if it could
affect a valve's leak-tightness. ``Alternate test or analysis'' are not
endorsed as appropriate substitutes for an as-found test, since the
latter provides clear and objective evidence of performance of
isolation components; and (3) limitation of the extension of test
intervals for main steam and feedwater isolation valves in BWRs, and
containment purge and vent valves in PWRs and BWRs beyond 30 months
given their operating experience and/or safety significance.
Regulatory Guide; Issuance, Availability
The Nuclear Regulatory Commission has issued a new guide in its
Regulatory Guide Series. This series has been developed to describe and
make available to the public such information as methods acceptable to
the NRC staff for implementing specific parts of the Commission's
regulations, techniques used by the staff in evaluating specific
problems or postulated accidents, and data needed by the staff in its
review of applications for permits and licenses.
Regulatory Guide 1.163, ``Performance-Based Containment Leakage-
Test Program,'' endorses an industry standard which contains guidance
on an acceptable performance-based leakage-test program, leakage rate
test methods, procedures, and analyses that may be used to implement
the final regulation published in this notice.
Comments and suggestions in connection with items for inclusion in
guides currently being developed or improvements in all published
guides are encouraged at any time. Written comments may be submitted to
the Rules Review and Directives Branch, Division of Freedom of
Information and Publications Services, Office of Administration, U.S.
Nuclear Regulatory Commission, Washington, DC 20555. The NRC staff's
response to public comments received on the draft version of this guide
(DG-1037, issued in February 1995) are available for inspection or
copying for a fee in the NRC Public Document Room, 2120 L Street NW.,
Washington, DC.
Regulatory guides are available for inspection at the Commission's
Public Document Room, 2120 L Street NW., Washington, DC. Single copies
of regulatory guides may be obtained free of charge by writing the
Office of Administration, Attention: Distribution and Services Section,
U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001; or by
fax at (301) 415-2260. Issued guides may also be purchased from the
National Technical Information Service on a standing order basis.
Details on this service may be
[[Page 49504]]
obtained by writing NTIS, 5285 Port Royal Road, Springfield, VA 22161.
Regulatory guides are not copyrighted, and Commission approval is not
required to reproduce them.
Implementation
The proposed Option B to Appendix J will become effective 30 days
after publication. At any time thereafter, a licensee or applicant may
notify the NRC of its desire to perform containment leakage-rate
testing according to Option B. Accompanying this notification, a
licensee must submit proposed technical specifications changes which
would eliminate those technical specifications which implement the
current rule and propose a new technical specification referencing the
NRC regulatory guide or, if the licensee desires, an alternative
implementation guidance. Implementation must await NRC review and
approval of the licensee's proposal. The NRC anticipates that a generic
communication will be issued shortly which will provide the
implementation procedure to all power reactor licensees.
Finding of No Significant Environmental Impact: Availability
The Commission has determined under the National Environmental
Policy Act of 1969, as amended, and the Commission's regulations in
Subpart A of 10 CFR Part 51, that this rule, if adopted, would not be a
major Federal action significantly affecting the quality of the human
environment, and therefore an environmental impact statement is not
required. There will be a marginal radiological environmental impact
offsite, and the occupational exposure onsite is expected to decrease
by about 0.8 person-rem per year of plant operation for plant personnel
if licensees adopt the performance-based testing scheme provided in the
revised regulation. Alternatives to issuing this revision of the
regulation were considered. One alternative would also entail complex
revisions to other NRC regulations and therefore the NRC has decided to
pursue it separately in the future. A third alternative would add
regulatory burden without a commensurate safety benefit and therefore
was found not to be acceptable. The environmental assessment is
available for inspection or copying for a fee in the NRC Public
Document Room, 2120 L Street NW, (Lower Level), Washington, DC; the
PDR's mailing address is Mail Stop LL-6, Washington, DC 20555; phone
(202) 634-3273; fax (202) 634-3343.
Paperwork Reduction Act Statement
This final rule amends information collection requirements that are
subject to the Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et
seq.). These requirements were approved by the Office of Management and
Budget, approval number 3150-0011.
Because the rule will relax existing information collection
requirements by providing an option to the existing requirements, the
public burden for this collection of information is expected to be
reduced by approximately 400 hours per licensee per year. This
reduction includes the time required for reviewing instructions,
searching existing data sources, gathering and maintaining the data
needed and completing and reviewing the collection of information. Send
comments regarding the estimated burden reduction or any aspect of this
collection of information, including suggestions for reducing this
burden, to the Information and Records Management Branch (T-6 F33),
U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001; and to
the Desk Officer, Office of Information and Regulatory Affairs, NEOB-
10202, (3150-0011), Office of Management and Budget, Washington, DC
20503.
Regulatory Analysis
The Commission has prepared a final regulatory analysis on this
regulation. The analysis examines the costs and benefits of the
alternatives considered by the Commission. The analysis is available
for inspection or copying for a fee in the NRC Public Document Room,
2120 L Street NW, (Lower Level), Washington, DC; the PDR's mailing
address is Mail Stop LL-6, Washington, DC 20555; phone (202) 634-3273;
fax (202) 634-3343.
Regulatory Flexibility Certification
In accordance with the Regulatory Flexibility Act of 1980, (5
U.S.C. 605(b)), the Commission certifies that this rule will not, if
promulgated, have a significant economic impact on a substantial number
of small entities. This rule affects only the licensing and operation
of nuclear power plants. The companies that own these plants do not
fall within the scope of the definition of ``small entities'' set forth
in the Regulatory Flexibility Act or the Size standard adopted by the
NRC (10 CFR 2.810).
Backfit Analysis
This final rule amends a current regulation by establishing
alternative requirements which may be voluntarily adopted by licensees.
Therefore, the final rule does not constitute a backfit as defined in
10 CFR 50.109(a)(1). Therefore, a backfit analysis is not necessary.
List of Subjects in 10 CFR Part 50
Antitrust, Classified information, Criminal penalties, Fire
protection, Incorporation by reference, Intergovernmental relations,
Nuclear power plants and reactors, Radiation protection, Reactor siting
criteria, Reporting and recordkeeping requirements.
For the reasons set out in the preamble and under the authority of
the Atomic Energy Act of 1954, as amended, the Energy Reorganization
Act of 1974, as amended, and 5 U.S.C. 552 and 553, the NRC is adopting
the following amendments to 10 CFR Part 50.
PART 50--DOMESTIC LICENSING OF PRODUCTION AND UTILIZATION
FACILITIES
1. The authority citation for Part 50 is revised to read as
follows:
Authority: Secs. 102, 103, 104, 105, 161, 182, 183, 186, 189, 68
Stat. 936, 937, 938, 948, 953, 954, 955, 956, as amended, sec. 234,
83 Stat. 1244, as amended (42 U.S.C. 2132, 2133, 2134, 2135, 2201,
2232, 2233, 2236, 2239, 2282); secs. 201, as amended, 202, 206, 88
Stat. 1242, as amended, 1244 1246 (42 U.S.C. 5841, 5842, 5846).
Section 50.7 also issued under Pub. L. 95-601, sec. 10, 92 Stat.
2951, as amended by Pub. L. 102-486, sec. 2902, 106 Stat. 3123, (42
U.S.C. 5851). Sections 50.10 also issued under secs. 101, 185, 68
Stat. 936, 955, as amended (42 U.S.C. 2131, 2235); sec. 102, Pub. L.
91-190, 83 Stat. 853 (42 U.S.C. 4332). Sections 50.13, 50.54(dd),
and 50.103 also issued under sec. 108, 68 Stat. 939, as amended (42
U.S.C. 2138). Sections 50.23, 50.35, 50.55, and 50.56 also issued
under sec. 185, 68 Stat. 955 (42 U.S.C. 2235). Sections 50.33a,
50.55a and Appendix Q also issued under sec. 102, Pub. L. 91-190, 83
Stat. 853 (42 U.S.C. 4332). Sections 50.34 and 50.54 also issued
under sec. 204, 88 Stat. 1245 (42 U.S.C. 5844). Sections 50.58,
50.91, and 50.92 also issued under Pub. L. 97-415, 96 Stat. 2073 (42
U.S.C. 2239). Section 50.78 also issued under sec. 122, 68 Stat. 939
(42 U.S.C. 2152). Sections 50.80 50.81 also issued under sec. 184,
68 Stat. 954, as amended (42 U.S.C. 2234). Appendix F also issued
under sec. 187, 68 Stat. 955 (42 U.S.C. 2237).
2. Appendix J to 10 CFR Part 50 is amended by adding the following
language between the title and the Table of Contents and adding the
language for Option B after Section V.B3.
Appendix J--Primary Reactor Containment Leakage Testing for Water-
Cooled Power Reactors
This appendix includes two options, A and B, either of which can
be chosen for meeting the requirements of this appendix.
[[Page 49505]]
Option A--Prescriptive Requirements
* * * * *
Option B--Performance-Based Requirements
Table of Contents
I. Introduction.
II. Definitions.
III. Performance-based leakage-test requirements.
A. Type A test.
B. Type B and C tests.
IV. Recordkeeping.
V. Application.
I. Introduction
One of the conditions required of all operating licenses for
light-water-cooled power reactors as specified in Sec. 50.54(o) is
that primary reactor containments meet the leakage-rate test
requirements in either Option A or B of this appendix. These test
requirements ensure that (a) leakage through these containments or
systems and components penetrating these containments does not
exceed allowable leakage rates specified in the Technical
Specifications and (b) integrity of the containment structure is
maintained during its service life. Option B of this appendix
identifies the performance-based requirements and criteria for
preoperational and subsequent periodic leakage-rate testing.3
\3\ Specific guidance concerning a performance-based leakage-
test program, acceptable leakage-rate test methods, procedures, and
analyses that may be used to implement these requirements and
criteria are provided in Regulatory Guide 1.163, ``Performance-Based
Containment Leak-Test Program.''
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II. Definitions
Performance criteria means the performance standards against
which test results are to be compared for establishing the
acceptability of the containment system as a leakage-limiting
boundary.
Containment system means the principal barrier, after the
reactor coolant pressure boundary, to prevent the release of
quantities of radioactive material that would have a significant
radiological effect on the health of the public.
Overall integrated leakage rate means the total leakage rate
through all tested leakage paths, including containment welds,
valves, fittings, and components that penetrate the containment
system.
La (percent/24 hours) means the maximum allowable leakage rate
at pressure Pa as specified in the Technical Specifications.
Pa (p.s.i.g) means the calculated peak containment internal
pressure related to the design basis loss-of-coolant accident as
specified in the Technical Specifications.
III. Performance-Based Leakage-Test Requirements
A. Type A Test
Type A tests to measure the containment system overall
integrated leakage rate must be conducted under conditions
representing design basis loss-of-coolant accident containment peak
pressure. A Type A test must be conducted (1) after the containment
system has been completed and is ready for operation and (2) at a
periodic interval based on the historical performance of the overall
containment system as a barrier to fission product releases to
reduce the risk from reactor accidents. A general visual inspection
of the accessible interior and exterior surfaces of the containment
system for structural deterioration which may affect the containment
leak-tight integrity must be conducted prior to each test, and at a
periodic interval between tests based on the performance of the
containment system. The leakage rate must not exceed the allowable
leakage rate (La) with margin, as specified in the Technical
Specifications. The test results must be compared with previous
results to examine the performance history of the overall
containment system to limit leakage.
B. Type B and C Tests
Type B pneumatic tests to detect and measure local leakage rates
across pressure retaining, leakage-limiting boundaries, and Type C
pneumatic tests to measure containment isolation valve leakage
rates, must be conducted (1) prior to initial criticality, and (2)
periodically thereafter at intervals based on the safety
significance and historical performance of each boundary and
isolation valve to ensure the integrity of the overall containment
system as a barrier to fission product release to reduce the risk
from reactor accidents. The performance-based testing program must
contain a performance criterion for Type B and C tests,
consideration of leakage-rate limits and factors that are indicative
of or affect performance, when establishing test intervals,
evaluations of performance of containment system components, and
comparison to previous test results to examine the performance
history of the overall containment system to limit leakage. The
tests must demonstrate that the sum of the leakage rates at accident
pressure of Type B tests, and pathway leakage rates from Type C
tests, is less than the performance criterion (La) with margin, as
specified in the Technical Specification.
IV. Recordkeeping
The results of the preoperational and periodic Type A, B, and C
tests must be documented to show that performance criteria for
leakage have been met. The comparison to previous results of the
performance of the overall containment system and of individual
components within it must be documented to show that the test
intervals established for the containment system and components
within it are adequate. These records must be available for
inspection at plant sites.
If the test results exceed the performance criteria (La) as
defined in the plant Technical Specifications, those exceedances
must be assessed for Emergency Notification System reporting under
Secs. 50.72 (b)(1)(ii) and Sec. 50.72 (b)(2)(i), and for a Licensee
Event Report under Sec. 50.73 (a)(2)(ii).
V. Application
A. Applicability
The requirements in either or both Option B, III.A for Type A
tests, and Option B, III.B for Type B and C tests, may be adopted on
a voluntary basis by an operating nuclear power reactor licensee as
specified in Sec. 50.54 in substitution of the requirements for
those tests contained in Option A of this appendix. If the
requirements for tests in Option B, III.A or Option B, III.B are
implemented, the recordkeeping requirements in Option B, IV for
these tests must be substituted for the reporting requirements of
these tests contained in Option A of this appendix.
B. Implementation
1. Specific exemptions to Option A of this appendix that have
been formally approved by the AEC or NRC, according to 10 CFR 50.12,
are still applicable to Option B of this appendix if necessary,
unless specifically revoked by the NRC.
2. A licensee or applicant for an operating license may adopt
Option B, or parts thereof, as specified in Section V.A of this
Appendix, by submitting its implementation plan and request for
revision to technical specifications (see paragraph B.3 below) to
the Director of the Office of Nuclear Reactor Regulation.
3. The regulatory guide or other implementation document used by
a licensee, or applicant for an operating license, to develop a
performance-based leakage-testing program must be included, by
general reference, in the plant technical specifications. The
submittal for technical specification revisions must contain
justification, including supporting analyses, if the licensee
chooses to deviate from methods approved by the Commission and
endorsed in a regulatory guide.
4. The detailed licensee programs for conducting testing under
Option B must be available at the plant site for NRC inspection.
Dated at Rockville, Maryland this 20th day of September, 1995.
For the Nuclear Regulatory Commission.
John C. Hoyle,
Secretary of the Commission.
[FR Doc. 95-23803 Filed 9-25-95; 8:45 am]
BILLING CODE 7590-01-P
