[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
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  Federal Register / Vol. 62, No. 232 / Wednesday, December 3, 1997 / 
Rules and Regulations  

[[Page 63825]]


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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 [email protected].

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

[[Page 63827]]

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.

[[Page 63828]]

    (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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