[Federal Register Volume 62, Number 215 (Thursday, November 6, 1997)]
[Notices]
[Pages 60109-60111]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-29343]
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NUCLEAR REGULATORY COMMISSION
[Docket No. 50-416]
Exemption
In the matter of Entergy Operations, Inc., System Energy
Resources, Inc., South Mississippi Electric Power Association,
Entergy Mississippi, Inc.; (Grand Gulf Nuclear Station, Unit 1)
I
Entergy Operations, Inc. (the licensee) is the holder of Facility
Operating License No. NPF-29, which authorizes operation of Grand Gulf
Nuclear Station, Unit 1 (GGNS). The operating license provides, among
other things, that the licensee is subject to all rules, regulations,
and orders of the Nuclear Regulatory Commission (NRC or the Commission)
now and hereafter in effect.
The facility is a General Electric boiling water reactor at the
licensee's site in Claiborne County, Mississippi.
II
Title 10 CFR 70.24, ``Criticality Accident Requirements,''
paragraph (a) states, in part, that ``Each licensee authorized to
possess special nuclear material [SNM] in a quantity exceeding 700
grams of contained uranium-235, 520 grams of contained uranium-233, 450
grams of plutonium, 1,500 grams of contained uranium-235 if no uranium
enriched to more than 4 percent by weight of uranium-235 is present,
450 grams of any combination thereof, or one-half such quantities if
massive moderators or reflectors made of graphite, heavy water or
beryllium may be present, shall maintain in each area in which such
licensed special nuclear material is handled, used, or stored, a
monitoring system meeting the requirements of [10 CFR 70.24](a)(1) or
(a)(2), as appropriate, and using gamma-or neutron-sensitive radiation
detectors which will energize clearly audible alarm signals if
accidental criticality occurs. This section is not intended to require
underwater monitoring when special nuclear material is handled or
stored beneath water shielding or to require monitoring systems when
special nuclear material is being transported when packaged in
accordance with the requirements of Part 71 [(i.e., 10 CFR Part 71,
``Packaging and Transportation of Radioactive Material,'')] of this
chapter.''
The licensee meets the quantity criteria in 10 CFR 70.24(a) and is,
therefore, required to have a criticality accident monitoring system in
each area in which SNM in any form is handled, used, or stored. The
licensee has proposed an exemption to this requirement for the storage
of two forms of SNM at the site: (1) not-in-use in-core nuclear
instrumentation (e.g., source range monitors) and (2) onsite
unirradiated fuel. For the unirradiated fuel, the exemption is
requested for the following cases:
The interval when the fuel, packaged for shipment to the
site in accordance with 10 CFR Part 71, is taken from the shipping
truck to the plant area where the Part 71 packaging is removed.
The storage of the unirradiated fuel in the new fuel vault
(NFV), instead of the spent fuel pool, after the packaging is removed.
The very small quantity of SNM present in the nuclear
instrumentation is in the form of thin coatings within the
instrumentation and the unirradiated fuel assemblies would only be
removed from the NRC-approved packaging in areas where criticality
monitors are in use, and stored in either the NFV or the
[[Page 60110]]
spent fuel pool. The unirradiated fuel that is stored in the spent fuel
pool would be monitored in accordance with 10 CFR 70.24(a), whereas
there is not a criticality accident monitor in the NFV.
An exemption from 10 CFR 70.24(a) is required for the licensee to
store SNM at the site and not have a criticality accident monitoring
system for the storage areas.
III
Pursuant to 10 CFR 70.14, ``Specific exemptions,'' the Commission
may, upon application of any interested person or upon its own
initiative, grant such exemptions from the requirements of the
regulations in this part as it determines are authorized by law and
will not endanger life or property or the common defense and security,
and are otherwise in the public interest.
Pursuant to 10 CFR 70.24(d), any licensee who believes that good
cause exists why it should be granted an exemption in whole or in part
from the requirements of this section may apply to the Commission for
such an exemption. Such application shall specify the reason for the
relief requested.
By letter dated July 15, 1996, as supplemented by letters dated
March 7 and April 29, 1997, the licensee requested an exemption from
the monitoring requirements of 10 CFR 70.24(a) for the storage of these
two forms of SNM at the site. In those letters, the licensee provided
the justification and reasons for requesting the exemption. The
licensee did not request an exemption to the performance requirements
of a criticality accident monitoring system that are specified in 10
CFR 70.24(a)(1) or (a)(2).
A previous exemption from the provisions of 10 CFR 70.24 for the
storage of SNM was granted for GGNS in the July 15, 1981, SNM License
No. 1882. This exemption expired with the SNM license when the
operating license was issued for GGNS because the exemption was not
reissued at that time. Therefore, the licensee has requested an
exemption from the criticality accident monitoring requirements of 10
CFR 70.24(a) specifically for the areas containing in-core
instrumentation detectors (which are not in use) and unirradiated
(fresh) fuel. For unirradiated fuel, the exemption is requested for the
unirradiated fuel that is in NRC-approved packaging while the fuel is
taken from the shipping trucks to the spent fuel pool area to be
removed from the packaging, and for the unirradiated fuel that is
stored in the NFV, instead of the spent fuel pool.
The principal form of SNM at GGNS is in the form of nuclear fuel.
Other quantities of SNM are also used or stored at the facility in the
form of fissile material incorporated into in-core nuclear
instrumentation (e.g., source range monitors, intermediate range
monitors, local power range monitors, and traversing in-core probes).
The instrumentation is being stored at the site within the security
fence in different plant areas.
The SNM in the nuclear instrumentation is in small quantities in
thin coatings applied to the inside of sealed fission chambers
contained within the instruments. The licensee has stated that the
total amount of SNM contained in the nuclear instruments meets the
``forms not sufficient to form a critical mass'' in Section 1.1 of
Regulatory Guide 10.3, ``Guide for the Preparation of Applications for
Special Nuclear Material Licenses of Less Than Critical Mass
Quantities,'' Revision 1, dated April 1977. Thus, the licensee has
committed that the total amount of SNM contained within in-core nuclear
instrumentation will be less than a critical mass. Therefore, the small
quantity of SNM in the nuclear instrumentation precludes inadvertent
criticality.
Unirradiated nuclear fuel is received at the site only in NRC-
approved Part 71 packaging. The entire Part 71 packaging consists of
two right rectangular boxes consisting of an outer wooden container
surrounding a inner metal container housing the unirradiated fuel.
There is only cushioning material between the two boxes. The containers
are designed in accordance with a certificate of compliance for
radioactive materials packages issued by the NRC, in this case for the
shipment of unirradiated fuel assemblies. It is the inner metal
container that ensures that a geometrically safe configuration of the
fuel is maintained during transport, handling, storage, and accident
conditions, and that the introduction of any moderating agents to the
fuel is precluded due to its leak-tight construction. Criticality is
precluded due to the construction of the package and the storage
configuration of the fuel in the package. This is based on a
criticality analysis of the Part 71 packaging which limits the number
of such packages on a shipping truck.
The handling of unirradiated fuel at the site is governed by
administrative and departmental procedures that specify New Fuel
Processing and Criticality Rules to ensure that fuel is not
inadvertently removed from the inner metal container until it is
positioned in the fuel inspection area near the spent fuel pool of the
auxiliary building where a criticality accident monitoring system
meeting 70.24(a) is present. It is the metal container that is referred
to when the licensee stated that the unirradiated fuel will only be
removed from the NRC-approved packaging in the presence of a
criticality accident monitoring system meeting 70.24(a).
The unirradiated fuel is brought onsite on shipping trucks. The
wooden containers are removed from the inner metal containers, and the
unirradiated fuel is lifted in the metal container to the 208-foot
level of the auxiliary building, and adjacent to the cask washdown pit
and NFV of the spent fuel pool area. Only one metal container is lifted
at a time, and the crane and lifting equipment used for the lift are
certified. The plant areas that the metal containers would be moved
through were inspected during a visit to the site and it was determined
that the areas have drains to prevent the possibility of submerging the
metal containers under water and creating a possible criticality
condition. The only practical plant area where the new fuel could be
submerged in water to introduce moderation is the spent fuel pool and
there are 70.24(a) monitors in that area.
In the spent fuel pool area, the fuel is removed from the
containers, inspected and channeled, and then placed either in the
spent fuel pool or the NFV. Currently the unirradiated fuel is placed
only in the spent fuel pool and, while the fuel is in the spent fuel
pool, it is monitored by a 70.24(a) monitoring system; however
unirradiated fuel may be stored inside the NFV and there is not a
criticality accident monitor in the NFV. The design basis criticality
margin requirements for the NFV is to maintain the unirradiated fuel in
the vault at a subcriticality margin of at least 0.05 (i.e., a k
effective no more than 0.95). The new fuel would be stored in racks
that are designed to withstand all credible static and dynamic loadings
to prevent damage and distortion of the racks, and to maintain the
design subcriticality margin of 0.05 whether the vault is dry or
flooded with unborated water, because unborated water would moderate
the fuel and reduce the subcriticality margin. The racks are
constructed in accordance with the quality assurance requirements of
Appendix B to 10 CFR Part 50 and are categorized as Safety Class 2 and
Seismic Category I. The vault is in a concrete, Seismic Category I
building that is designed to Regulatory Guides 1.13 and 1.29 which
precludes the deleterious effects on the fuel in the NFV by natural
phenomena such as
[[Page 60111]]
earthquakes, tornados, hurricanes, tornado missiles, and floods. To
prevent water moderation, there is a drain at the low point of the
vault to remove water in the vault to prevent accumulation of water
within the NFV and no fuel is placed in the vault if there is water in
the vault. The licensee also has procedures to prevent the introduction
of an optimum moderation inside the vault (e.g., using pressurized
water fire extinguishers instead of foam for combating fires around
fuel) which could decrease the subcriticality margin to a value greater
than the design value of 0.05. Although the Technical Specifications
for Grand Gulf do not specifically limit the enrichment of the fuel
onsite including the NFV, the k-effective for spent fuel or new fuel in
the fuel racks and submerged in water is limited to 0.95 by the
Technical Specifications and the enrichment of the fuel onsite is
limited because the k-effective for the NFV is not allowed to be
greater than 0.95. The fuel enrichment is a contributor to the value of
k-effective. Therefore, the design of the NFV will preclude inadvertent
criticality of the new fuel in the vault.
Therefore, based on the licensee's letters and the staff's
evaluation, the Commission concludes that good cause exists for
granting an exemption to the criticality monitoring requirements of 10
CFR 70.24(a) in storage areas for (1) in-core instrumentation detectors
which are not in use and (2) unirradiated fuel stored in the NFV. Based
on the information provided by the licensee, there is reasonable
assurance that the nuclear instrumentation and unirradiated fuel will
remain subcritical during handling and storage in areas where
critically accident monitors required by 10 CFR 70.24(a) are not
present. Additionally, all fuel storage and handling areas will
continue to be monitored to detect conditions that may result in
excessive radiation levels as required by General Design Criterion 63.
IV
For the foregoing reasons, pursuant to 10 CFR 70.24(d), the NRC
staff has determined that good cause has been shown for granting an
exemption to the criticality monitoring requirements of 10 CFR
70.24(a).
Accordingly, the Commission has determined that, pursuant to 10 CFR
70.14, an exemption is authorized by law, will not endanger life or
property or common defense and security, and is otherwise in the public
interest. Therefore, with the total amount of SNM contained in the in-
core nuclear instruments less than a critical mass, as defined by
Section 1.1 of Regulatory Guide 10.3 (Revision 1, dated April 1977),
with the unirradiated fuel assemblies only removed from the NRC-
approved metal containers in areas where criticality monitors are
present, and with administrative controls to prevent optimum moderation
of the unirradiated fuel in the NFV, the Commission hereby grants
Entergy Operations, Inc. an exemption from the criticality monitoring
requirements of 10 CFR 70.24(a) for the storage of not-in-use in-core
nuclear instrumentation and of unirradiated fuel in the NFV.
Pursuant to 10 CFR 51.32, the Commission has determined that the
granting of this exemption will have no significant impact on the
quality of the human environment (62 FR 55837). This exemption is
effective upon issuance.
Dated at Rockville, Maryland, this 31st day of October 1997.
For the Nuclear Regulatory Commission.
Samuel J. Collins,
Director, Office of Nuclear Reactor Regulation.
[FR Doc. 97-29343 Filed 11-5-97; 8:45 am]
BILLING CODE 7590-01-P
