[Federal Register Volume 60, Number 171 (Tuesday, September 5, 1995)]
[Notices]
[Pages 46135-46137]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-21929]
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NUCLEAR REGULATORY COMMISSION
[Docket No. 50-424]
Georgia Power Company, et al. (Vogtle Electric Generating Plant,
Unit 1); Exemption
I
Georgia Power Company, et al. (the licensee) is the holder of
Facility Operating License No. NPR-68, which authorizes operation of
the Vogtle Electric Generating Plant (VEGP), Unit 1. The license
provides, among other things, that the licensee is subject to all
rules, regulations, and orders of the Commission now or hereafter in
effect.
The facility consists of a pressurized water reactor, VEGP Unit 1,
at the licensee's site located near Waynesboro, Georgia.
II
Section III.D.1.(a) of Appendix J to 10 CFR Part 50 requires the
performance of three Type A containment integrated leakage rate tests
(ILRTs), at approximately equal intervals during each 10-year service
period of the primary containment. The third test of each set shall be
conducted when the plant is shutdown for the 10-year inservice
inspection of the primary containment.
III
By letter dated May 12, 1995, as supplemented by letter dated June
6, 1995, the licensee requested temporary relief from the requirement
to perform a set of three Type A tests at approximately equal intervals
during each 10-year service period of the primary containment. The
requested exemption would permit a one-time interval extension of the
third Type A test by approximately 18 months (from the March, 1996,
refueling outage, to the September, 1997, refueling outage) and would
permit the third Type A test of the second 10-year inservice inspection
period to not correspond with the end of the current American Society
of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code)
inservice inspection interval.
The licensee's request cites the special circumstances of 10 CFR
50.12, paragraph (a)(2) (ii), (iii) and (vi) as the basis for the
exemption. They point out that the existing Type B and C testing
programs are not being modified by this request and will continue to
effectively detect containment leakage caused by the degradation of
active containment isolation components as well as containment
penetrations. It has been the experience at Vogtle Unit 1 during the
three Type A tests (one preoperational and two during the first 10 year
inservice inspection period) conducted from 1986 to date, that any
significant containment leakage paths are detected by the Type B and C
testing. The Type A test results have only been confirmatory of the
results of the Type B and C test results. Therefore, application of the
regulation in this particular circumstance is not necessary to achieve
the underlying purpose of the rule.
Additionally, the licensee stated that their exemption request
meets the requirements of 10 CFR 50.12 for the following reasons:
10 CFR 50.12 Requirements
In accordance with 10 CFR 50.12, the Commission may grant an
exemption to the requirements of the regulations of 10 CFR 50 if the
exemption is authorized by law, will not present an undue risk to
the public health and safety, is consistent with the common defense
and security, and special circumstances are present.
The Requested Exemption is Authorized by Law
There is no known law that would be violated by the granting of
the proposed exemption. 10 CFR 50.12 provides the basis for granting
exemptions to the requirements of 10 CFR 50 regulations. The NRC has
granted similar exemptions in the past. Therefore, the exemption is
authorized by law.
The Requested Exemption Does Not Present an Undue Risk to the
Public Health and Safety
10 CFR 50, Appendix J states that the purpose of the regulation
is to assure that leakage through primary containment and systems
and components penetrating containment does not exceed allowable
values, as specified in the Technical Specifications or associated
bases, and that proper maintenance and repair are performed
throughout the service life of the containment boundary components.
The ILRT history for VEGP, Unit 1 during the first 10 year service
period inspection interval indicated that the containment structure
has not experienced degradation. The NRC has conducted a detailed
study of integrated leak rate tests performed from 1987 to 1993.
That study, documented in draft NUREG-1493, determined that 97% of
the leakage rate tests that exceed the acceptance criteria are
identified by LLRT programs. The LLRT program at VEGP, Unit 1 has
been successful in maintaining low Type B and C containment leakage.
Since there has been no identified containment structural leakage,
the
[[Page 46136]]
LLRT program has contributed to the successful ILRTs. Therefore, as
shown in the NRC study and as indicated by the VEGP, Unit 1
containment performance history, postponing the ILRT by one
refueling cycle remains consistent with the intent of the regulation
and will not present an undue risk to the public health and safety.
The Requested Exemption Will Not Endanger the Common Defense and
Security
GPC interprets the term ``common defense and security'' as
referring principally to the safeguarding of special nuclear
material, the absence of foreign control over the applicant, and the
protection of restricted data. The granting of the requested
exemption will not affect any of those matters, and thus, the
granting of the exemption is consistent with the common defense and
security of the United States.
Special Circumstances are Present Which Necessitate the Request for
an Exemption to the Regulations of 10 CFR 50, Appendix J, Section
III.A.5(b)(2)
The special circumstances of 10 CFR 50.12(a)(2) (ii), (iii), and
(vi) apply to this requested exemption.
50.12(a)(2)(ii)--Application of the Regulation is Not Necessary to
Achieve the Underlying Purpose of the Rule
The underlying purpose of 10 CFR 50, Appendix J will still be
served if a third ILRT is not conducted during the first 10-year
service period. Appendix J states that the leakage test requirements
provide for periodic verification by tests of the leak tight
integrity of the primary reactor containment. The Appendix further
states that the purpose of the tests is to assure that leakage
through the primary reactor containment shall not exceed the
allowable leakage rate values as specified in the Technical
Specifications or associated bases.
10 CFR 50, Appendix J, Section III.D.1(a) states that a set of
three periodic tests shall be performed at approximately equal
intervals during each 10-year period and that the third test shall
be conducted when the plant is shut down for the 10-year plant
inservice inspections. The proposed exemption would permit delaying
of the scheduled Type A test and permit performance of the Type A
test after the completion of the first 10-year inservice inspection
interval in accordance with the schedule to be provided in the
proposed revision to Appendix J. The methodology, acceptance
criteria, and Technical Specifications leakage limits for
performance of the Type A test will not change.
The testing history, structural capability of the containment,
and the risk assessment discussed previously establish that 1) VEGP,
Unit 1 has had acceptable containment leakage rate test results, 2)
the structural integrity of containment is assured, and 3) there is
negligible risk impact in changing the Type A test schedule on a
one-time basis.
Thus, there is significant assurance that the extended interval
between Type A tests in concert with the Type B and C testing
continue to provide periodic verification of the leak tight
integrity of the containment.
10 CFR 50.12(a)(2)(iii)--Compliance With the Regulation Would
Result in Undue Hardship or Other Costs That Are Significantly in
Excess of Those Contemplated When the Regulation Was Adapted
Postponing the ILRT for VEGP, Unit 1 will eliminate unnecessary
testing without any reduction in plant safety. The ILRT typically
requires two-to-three days to perform, with the possibility of
significant extended time requirements. Outage activities are
severely impacted during the preparation period prior to the ILRT
and during the performance of the ILRT. A cost savings can be
realized by a reduction in outage time, eliminating the impact of
the ILRT on other outage activities, and direct costs related to
obtaining equipment and services necessary for performance of the
ILRT. This proposed exemption could result in a total cost benefit
of about $1,100,000, by eliminating one ILRT.
10 CFR 50.12(a)(2)(vi)--Presence of Material Circumstances Not
Considered When the Regulation Was Adopted
Certain material circumstances were not considered when the
regulation was adopted. The benefit of time has provided experience
and information that give a better perspective about containment
integrity. Two important material circumstances are testing history
and the development of probabilistic risk assessments (PRAs).
Since the promulgation of 10 CFR 50, Appendix J, in 1973, more
than 20 years of nuclear power plant operating experience has been
obtained. A review of industry data did not find any instances where
a Type A test failed to meet Appendix J acceptance criteria as a
result of a containment structural leak not due to initial
fabrication or a plant modification. That operating history provides
a significant indicator that containment structural integrity
(passive structure) is not a significant safety concern.
Plant specific PRAs were not available in 1973, and therefore,
were not considered when the regulation requiring compliance with
Appendix J [10 CFR 50.54(o)] was adopted. Overall plant risk due to
containment leakage is relatively small given the small probability
of containment leakage itself. The predominant contributor to
degraded containment integrity is the phenomenological effects of a
severe accident, not pre-existing containment integrity conditions.
An assessment of the risk impact in the exemption request indicates
that there is no undue risk to the public health and safety as a
result of the proposed scheduler extension of the Type A test.
There have been no modifications to the containment structure or
liner that would impact the overall containment integrity and leak
tightness.
IV
Section III.D.1.(a) of Appendix J to 10 CFR Part 50 states that a
set of three Type A leakage rate tests shall be performed at
approximately equal intervals during each 10-year service period.
The licensee proposes an exemption to this section which would
provide a one-time interval extension for the Type A test by
approximately 18 months. The Commission has determined that pursuant to
10 CFR 50.12(a)(1) this exemption is authorized by law, will not
present an undue risk to the public health and safety, and is
consistent with the common defense and security. The Commission further
determines that special circumstances as provided in 10 CFR
50.12(a)(2)(ii) are present justifying the exemption. Specifically,
these circumstances are that application of the regulation in the
particular circumstances is not necessary to achieve the underlying
purpose of the rule. The purpose of the tests is to assure that leakage
through the primary reactor containment shall not exceed allowable
leakage rate values. The staff has concluded, for the reasons set forth
herein, that the purpose of the rule will continue to be achieved with
the licensee's proposed exemption.
The NRC staff has reviewed the basis and supporting information
provided by the licensee in the exemption request. The NRC staff has
noted that the licensee has a good record of ensuring a leak-tight
containment. All of the Type A tests have passed and the licensee has
noted that the results of the Type A testing have been confirmatory of
the Type B and C tests which will continue to be performed. The
licensee will perform the general containment inspection although it is
only required by Appendix J (Section V.A.) to be performed in
conjunction with Type A tests. The NRC staff considers that these
inspections, though limited in scope, provide an important added level
of confidence in the continued integrity of the containment boundary.
The NRC staff has also made use of a draft staff report, NUREG-
1493, which provides the technical jusification for the present
Appendix J rulemaking effort which also includes a 10-year test
interval for Type A tests. The integrated leakage rate test, or Type A
test, measures overall containment leakage. However, operating
experience with all types of containments used in this country
demonstrates that essentially all containment leakage can be detected
by local leakage rate tests (Type B and C). According to results given
in NUREG-1493, out of 180 ILRT reports covering 110 individual reactors
and approximately 770 years of operating history, only 5 ILRT failures
were found which local leakage rate testing could not detect. This is
3% of all failures. This study agrees well with previous NRC staff
studies which show that Type B and C testing can detect a very large
percentage of containment leaks.
[[Page 46137]]
The Nuclear Management and Resources Council (NUMARC), now the
Nuclear Energy Institute (NEI), collected and provided the NRC staff
with summaries of data to asssist in the Appendix J rulemaking effort.
NUMARC collected results of 144 ILRTs from 33 units; 23 ILRTs exceeded
1.0La. Of these, only nine were not due to Type B or C leakage
penalties. The NEI data also added another perspective. The NEI data
show that in about one-third of the cases exceeding allowable leakage,
the as-found leakage was less than 2La; in one case the leakage
was found to be approximately 2La; in one case the as-found
leakage was less than 3La; one case approached 10La; and in
one case the leakage was found to be approximately 21La. For about
half of the failed ILRTs, the as-found leakage was not quantified.
These data show that, for those ILRTs for which the leakage was
quantified, the leakage values are small in comparison to the leakage
value at which the risk to the public starts to increase over the value
of risk corresponding to La (approximately 200La, as
discussed in NUREG-1493).
Based on generic and plant specific data, the NRC staff finds the
basis for the licensee's proposed exemption to allow a one-time
exemption to permit a schedular extension of one cycle for the
performance of the Appendix Type A test to be acceptable.
Pursuant to 10 CFR 51.32, the Commission has determined that
granting this Exemption will not have a significant impact on the
environment (60 FR 44514).
This Exemption is effective upon issuance and shall expire at the
completion of the 1997 refueling outage.
Dated at Rockville, Maryland, this 29th day of August 1995.
For the Nuclear Regulatory Commission.
Steven A. Varga,
Director, Division of Reactor Projects--I/II, Office of Nuclear Reactor
Regulation.
[FR Doc. 95-21929 Filed 9-1-95; 8:45 am]
BILLING CODE 7590-01-P
