[Federal Register Volume 62, Number 232 (Wednesday, December 3, 1997)]
[Rules and Regulations]
[Pages 63825-63828]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-31733]
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Rules and Regulations
Federal Register
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Federal Register / Vol. 62, No. 232 / Wednesday, December 3, 1997 /
Rules and Regulations
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NUCLEAR REGULATORY COMMISSION
10 CFR Parts 50 and 70
RIN 3150-AF87
Criticality Accident Requirements
AGENCY: Nuclear Regulatory Commission.
ACTION: Direct final rule with opportunity to comment.
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SUMMARY: The Nuclear Regulatory Commission (NRC) is amending its
regulations to provide light-water nuclear power reactor licensees with
greater flexibility in meeting the requirement that licensees
authorized to possess more than a small amount of special nuclear
material (SNM) maintain a criticality monitoring system in each area
where the material is handled, used, or stored. This action is taken as
a result of the experience gained in processing and evaluating a number
of exemption requests from power reactor licensees and NRC's safety
assessments in response to these requests that concluded that the
likelihood of criticality was negligible.
EFFECTIVE DATE: The final rule is effective February 17, 1998, unless
significant adverse comments are received by January 2, 1998. If the
effective date is delayed, timely notice will be published in the
Federal Register.
ADDRESSES: Mail comments to: Secretary, U.S. Nuclear Regulatory
Commission, Washington, DC 20555-0001, Attention: Rulemaking and
Adjudications Staff.
Hand deliver comments to 11555 Rockville Pike, Maryland, between
7:30 am and 4:15 pm on Federal workdays.
Copies of any comments received may be examined at the NRC Public
Document Room, 2120 L Street NW. (Lower Level), Washington, DC.
For information on submitting comments electronically, see the
discussion under Electronic Access in the Supplementary Information
section.
FOR FURTHER INFORMATION CONTACT: Stan Turel, Office of Nuclear
Regulatory Research, U.S. Nuclear Regulatory Commission, Washington, DC
20555-0001, telephone (301) 415-6234, e-mail spt@nrc.gov.
SUPPLEMENTARY INFORMATION:
Background
The Nuclear Regulatory Commission (NRC) is amending its regulations
to provide persons licensed to construct or operate light-water nuclear
power reactors with the option of either meeting the criticality
accident requirements of paragraph (a) of 10 CFR 70.24 in handling and
storage areas for SNM, or electing to comply with certain requirements
that would be incorporated into 10 CFR Part 50. These are generally the
requirements that the NRC has used to grant specific exemptions to the
requirements of 10 CFR 70.24. In addition, the NRC is revising the
current text of the section relating to seeking specific exemptions
from regulations in 10 CFR 70.24(d) which provided that a licensee
could seek an exemption to all or part of 10 CFR 70.24 for good cause
because it is redundant to 10 CFR 70.14(a). A modified 10 CFR 70.24(d)
is being added to provide that the requirements in paragraph (a)
through (c) of 10 CFR Part 70.24 do not apply to holders of a
construction permit or operating license for a nuclear power reactor
issued pursuant to 10 CFR Part 50, or combined licenses issued under 10
CFR Part 52, if the holders comply with the requirements of 10 CFR
50.68 (b).
The Commission's regulations in 10 CFR 70.24 require that each
licensee authorized to possess more than a small amount of SNM maintain
a criticality monitoring system ``using gamma- or neutron-sensitive
radiation detectors which will energize clearly audible alarm signals
if accidental criticality occurs'' in each area in which such material
is handled, used, or stored. The regulation also specifies sensitivity
requirements for these monitors and details the training that licensees
must conduct in connection with criticality monitor alarms. The purpose
of this section is to ensure that if a criticality were to occur during
the handling of SNM, personnel would be alerted and would take
appropriate action.
Most nuclear power plant licensees were granted exemptions from 10
CFR 70.24 during the construction of their plants as part of the 10 CFR
Part 70 license issued to permit the receipt of the initial core.
Generally, these exemptions were not explicitly renewed when the 10 CFR
Part 50 operating license, which now contained the combined Part 50 and
Part 70 authority, was issued. The requirements in 10 CFR 70.24
prescribe the attributes required of the monitoring and alarm system.
Compliance with these requirements may be unnecessary for commercial
power reactors where the conditions which could lead to a criticality
event are so unlikely that the probability of occurrence of an
inadvertent criticality is negligible. The NRC anticipated that the
regulation might be unnecessary for some licensees and included in 10
CFR 70.24(d) an invitation to any licensee to seek an exemption to the
entire section or part of the section for good cause. A large number of
exemption requests have been submitted by power reactor licensees and
approved by the NRC based on safety assessments which concluded that
the likelihood of criticality was negligible. Because of the experience
gained in processing these exemption requests, the NRC concluded that
the regulations should be amended to provide this flexibility without
requiring licensees to go through the exemption process.
Discussion
At a commercial nuclear power plant, the reactor core, the fresh
fuel delivery area, the fresh fuel storage area, the spent fuel pool,
and the transit areas among these, are areas where amounts of SNM
sufficient to cause a criticality exist. In addition, SNM may be found
in laboratory and storage locations of these plants, but an inadvertent
criticality is not considered credible in these areas due to the amount
and configuration of the SNM. The SNM that could be assembled into a
critical mass at a commercial nuclear power plant is only in the form
of nuclear fuel. Nuclear power plant licensees have procedures and the
plants have design features to prevent inadvertent criticality. The
inadvertent criticality that 10 CFR 70.24 is intended to address could
only occur during fuel-handling operations.
[[Page 63826]]
In contrast, at fuel fabrication facilities SNM is found and
handled routinely in various configurations in addition to fuel.
Although the handling of SNM at these facilities is controlled by
procedures, the variety of forms of SNM and the frequency with which it
is handled provides greater opportunity for an inadvertent criticality
than at a nuclear power reactor.
At power reactor facilities with uranium fuel nominally enriched to
no greater than five (5.0) percent by weight, the SNM in the fuel
assemblies cannot go critical without both a critical configuration and
the presence of a moderator. Further, the fresh fuel storage array and
the spent fuel pool are in most cases designed to prevent inadvertent
criticality, even in the presence of an optimal density of unborated
moderator. Inadvertent criticality during fuel handling is precluded by
limitations on the number of fuel assemblies permitted out of storage
at the same time. In addition, General Design Criterion (GDC) 62 in
Appendix A to 10 CFR Part 50 reinforces the prevention of criticality
in fuel storage and handling through physical systems, processes, and
safe geometrical configuration. Moreover, fuel handling at power
reactor facilities occurs only under strict procedural control.
Therefore, the NRC considers a fuel-handling accidental criticality at
a commercial nuclear power plant to be extremely unlikely. The NRC
believes the criticality monitoring requirements of 10 CFR 70.24 are
unnecessary as long as design and administrative controls are
maintained.
Because the NRC considers an inadvertent criticality to be unlikely
at a nuclear power reactor, by this rulemaking it is granting nuclear
power reactor licensees a choice--either meet the criticality
monitoring requirements of 10 CFR 70.24 or in lieu of those criticality
monitoring requirements meet certain criteria related to procedures,
plant design, and fuel enrichment. These criteria are incorporated into
section 50.68(b) of 10 CFR Part 50 by this direct final rule.
The three changes in the requirements are as follows:
(1) Section 50.68(a) provides that each holder of a construction
permit or operating license for a nuclear power reactor issued under
Part 50, or a combined license for a nuclear power reactor issued under
Part 52 shall comply with either 10 CFR 70.24 or the seven requirements
in section 50.68(b).
(2) Section 50.68(b) provides that each licensee as described in
50.68(a) shall comply with the seven listed requirements in lieu of
maintaining a monitoring system capable of detecting a criticality as
described in 10 CFR 70.24.
(3) The revised section 70.24(d) provides that the requirements in
10 CFR 70.24 (a) through (c) do not apply to holders of a construction
permit or operating license for a nuclear power reactor issued pursuant
to 10 CFR Part 50, or combined licenses issued under 10 CFR Part 52, if
the holders comply with the requirements of paragraph (b) of 10 CFR
50.68.
Procedural Background
Because NRC considers these amendments to its rules to be
noncontroversial and routine, public comment on these amendments is
unnecessary. The amendments to the rules will become effective on
February 17, 1998. However, if the NRC receives significant adverse
comments on the companion proposal published concurrently in the
proposed rules section of this Federal Register by January 2, 1998,
then the NRC will publish a document that withdraws this action and
will address the comments received in response to the amendments. Such
comments will be addressed in a subsequent final rule. The NRC will not
initiate a second comment period on this action.
Findings
Upon review of this rulemaking, that the changes and additions
addressed by this rulemaking do not significantly affect the
environmental cost-benefit balance that otherwise would justify the
licensing of a light-water nuclear power reactor. The basis for this
finding is that this rule is a codification of practices in place and
does not significantly affect the cost-benefit balance for a light-
water reactor.
Metric Policy
On October 7, 1992, the Commission published its final Policy
Statement on Metrication. According to that policy, after January 7,
1993, all new regulations and major amendments to existing regulations
were to be presented in dual units. The new addition and amendment to
the regulations contain no units.
Environmental Impact: Categorical Exclusion
The NRC has determined that this proposed regulation is the type of
action described in categorical exclusion 10 CFR 51.22(c)(3). Therefore
neither an environmental impact statement nor an environmental
assessment has been prepared for this proposed regulation.
Electronic Access
You may also provide comments via the NRC's interactive rulemaking
web site through the NRC home page (http://www.nrc.gov). This site
provides the availability to upload comments as files (any format), if
your web browser supports that function. For information about the
interactive rulemaking site, contact Ms. Carol Gallagher, (301) 415-
6215; e-mail [email protected]
Paperwork Reduction Act Statement
This direct final rule does not contain a new or amended
information collection requirement subject to the Paperwork Reduction
Act of 1995 (44 U.S.C. 3501 et seq.). Existing requirements were
approved by the Office of Management and Budget, approval numbers 3150-
0009 and 3150-0011.
Public Protection Notification
If an information collection does not display a currently valid OMB
control number, the NRC may not conduct or sponsor, and a person is not
required to respond to, the information collection.
Regulatory Analysis
The structure of the current 10 CFR 70.24 is overly broad and
places burden on a licensee to identify those areas or operations at
its facility where the requirements are unnecessary, and to request an
exemption if the licensee has sufficient reason to be relieved from the
requirements. This existing structure has the potential to result in a
large number of recurring exemption requests.
To relieve the burden on power reactor licensees of applying for,
and the burden on the staff of granting recurring exemptions, this
amendment permits power reactor facilities with nominal fuel
enrichments no greater than 5 weight percent U-235 to be excluded from
the scope of 10 CFR 70.24, provided they meet specific requirements
being added to 10 CFR Part 50. This amendment is a result of the
experience gained in processing and evaluating a number of exemption
requests from power reactor licensees and NRC's safety assessments in
response to these requests that concluded that the likelihood of
criticality was negligible.
The only other viable option to this amendment is for the NRC to do
nothing and allow the licensees to continue requesting exemptions. If
nothing is done, the licensees will continue to incur the costs of
submitting exemptions and NRC will incur the costs of reviewing them.
Under this rule, an easing of burden on the part of
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licensees results by their not having to request exemptions. Similarly,
the NRC will not need to review and evaluate these exemption requests,
resulting in an easing of burden for the NRC.
This rule is not a mandatory requirement, but an easing of burden
action which results in regulatory efficiency. Also, the rule does not
impose any additional costs on licensees, has no negative impact on the
public health and safety, but will provide certain licensees savings,
and savings to the NRC as well. Hence, the rule is shown to be cost
beneficial.
The foregoing constitutes the regulatory analysis for this final
rule.
Regulatory Flexibility Certification
In accordance with the Regulatory Flexibility Act of 1980, 5 U.S.C.
605(b), the Commission hereby certifies that this rule, if adopted,
will not have a significant economic impact on a substantial number of
small entities. This rule affects only the licensees of nuclear power
plants. These licensees, companies that are dominant in their service
areas, do not fall within the scope of the definition of ``small
entities'' set forth in the Regulatory Flexibility Act, 5 U.S.C. 601,
or the size standards adopted by the NRC (10 CFR 2.810).
Backfit Analysis
The Commission has determined that a backfit analysis is not
needed. This rule is a codification of practices in place by the NRC
and is not a modification of or addition to systems, structures,
components, or design of a facility; or the design approval or
manufacturing license for a facility; or the procedures of organization
required to design, construct or operate a facility; any of which may
result from a new or amended provision in the Commission rules or the
imposition of a regulatory staff position interpreting the Commission
rules that is either new or different from a previously applicable NRC
staff position (10 CFR Chapter I).
Small Business Regulatory Enforcement Fairness Act
In accordance with the Small Business Regulatory Enforcement
Fairness Act of 1996, the NRC has determined that this action is not a
``major rule'' and has verified this determination with the Office of
Information and Regulatory Affairs, Office of Management and Budget.
List of Subjects
10 CFR Part 50
Antitrust, Classified information, Criminal penalties, Fire
prevention, Intergovernmental relations, Nuclear power plants and
reactors, Radiation protection, Reactor siting criteria, Reporting and
recordkeeping requirements.
10 CFR Part 70
Criminal penalties, Hazardous materials transportation, Material
control and accounting, Nuclear materials, Packaging and containers,
Radiation protection, Reporting and recordkeeping requirements,
Scientific equipment, Security measures, Special nuclear material.
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, the National Environmental Policy Act of 1969,
as amended, and 5 U.S.C. 553, the NRC is adopting the following
amendments to 10 CFR Parts 50 and 70.
PART 50--DOMESTIC LICENSING OF PRODUCTION AND UTILIZATION
FACILITIES
1. The authority citation for 10 CFR Part 50 continues 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. 444, 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. Section 50.68 is added under the center heading ``Issuance,
Limitations, and Conditions of Licenses and Construction Permits'' to
read as follows:
Sec. 50.68 Criticality accident requirements.
(a) Each holder of a construction permit or operating license for a
nuclear power reactor issued under this part, or a combined license for
a nuclear power reactor issued under part 52 of this chapter shall
comply with either 10 CFR 70.24 of this chapter or requirements in
paragraph (b).
(b) Each licensee shall comply with the following requirements in
lieu of maintaining a monitoring system capable of detecting a
criticality as described in 10 CFR 70.24:
(1) Plant procedures may not permit handling and transportation at
any one time of more fuel assemblies than have been determined to be
safely subcritical under the most adverse moderation conditions
feasible by unborated water.
(2) The estimated ratio of neutron production to neutron absorption
and leakage (k-effective) of the fresh fuel in the fresh fuel storage
racks shall be calculated assuming the racks are loaded with fuel of
the maximum permissible U-235 enrichment and flooded with pure water
and must not exceed 0.95, at a 95 percent probability, 95 percent
confidence level.
(3) If optimum moderation of fresh fuel in the fresh fuel storage
racks occurs when the racks are assumed to be loaded with fuel of the
maximum permissible U-235 enrichment and filled with low-density
hydrogenous fluid, the k-effective corresponding to this optimum
moderation must not exceed 0.98, at a 95 percent probability, 95
percent confidence level.
(4) If no credit for soluble boron is taken, the k-effective of the
spent fuel storage racks loaded with fuel of the maximum permissible U-
235 enrichment must not exceed 0.95, at a 95 percent probability, 95
percent confidence level, if flooded with pure water. If credit is
taken for soluble boron, the k-effective of the spent fuel storage
racks loaded with fuel of the maximum permissible U-235 enrichment must
not exceed 0.95, at a 95 percent probability, 95 percent confidence
level, if flooded with borated water, and the k-effective must remain
below 1.0 (subcritical), at a 95 percent probability, 95 percent
confidence level, if flooded with pure water.
(5) The quantity of SNM, other than nuclear fuel stored on site, is
less than the quantity necessary for a critical mass.
(6) Radiation monitors, as required by GDC 63, are provided in
storage and associated handling areas when fuel is present to detect
excessive radiation levels and to initiate appropriate safety actions.
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(7) The maximum nominal U-235 enrichment of the fresh fuel
assemblies is limited to no greater than five (5.0) percent by weight.
PART 70--DOMESTIC LICENSING OF SPECIAL NUCLEAR MATERIAL
1. The authority citation for 10 CFR Part 70 continues to read as
follows:
Authority: Secs. 51, 53, 161, 182, 183, 68 Stat. 929, 930, 948,
953, 954, as amended, sec. 234, 83 Stat. 444, as amended, sec. 1701,
106 Stat. 2951, 2952, 2953 (42 U.S.C. 2071, 2073, 2201, 2232, 2233,
2282, 2297f); secs. 201, as amended, 202, 204, 206, 88 Stat. 1242,
as amended, 1244, 1245, 1246, (42 U.S.C. 5841, 5842, 5845, 5846).
Sections 70.1(c) and 70.20a(b) also issued under secs. 135, 141,
Pub. L. 97-425, 96 Stat. 2232, 2241 (42 U.S.C. 10155, 10161).
Section 70.7 also issued under Pub. L. 95-601, sec. 10, 92 Stat.
2951 (42 U.S.C. 5851). Section 70.21(g) also issued under sec. 122,
68 Stat. 939 (42 U.S.C. 2152). Section 70.31 also issued under sec.
57d, Pub. L. 93-377, 88 Stat. 475 (42 U.S.C. 2077). Sections 70.36
and 70.44 also issued under sec. 184, 68 Stat. 954, as amended (42
U.S.C. 2234).
Section 70.61 also issued under secs. 186, 187, 68 Stat. 955 (42
U.S.C. 2236, 2237). Section 70.62 also issued under sec. 108, 68
Stat. 939, as amended (42 U.S.C. 2138).
2. In Sec. 70.24, paragraph (d) is revised to read as follows:
Sec. 70.24 Criticality accident requirements.
* * * * *
(d) The requirements in paragraph (a) through (c) of this section
do not apply to holders of a construction permit or operating license
for a nuclear power reactor issued pursuant to part 50 of this chapter,
or combined licenses issued under part 52 of this chapter, if the
holders comply with the requirements of paragraph (b) of 10 CFR 50.68
of this chapter.
Dated at Rockville, Maryland this 14th day of November, 1997.
For the Nuclear Regulatory Commission.
L. Joseph Callan,
Executive Director for Operations.
[FR Doc. 97-31733 Filed 12-2-97; 8:45 am]
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