[Federal Register Volume 62, Number 144 (Monday, July 28, 1997)]
[Notices]
[Pages 40388-40389]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-19802]
[[Page 40388]]
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NUCLEAR REGULATORY COMMISSION
[Docket Nos. 50-317 and 50-318]
Baltimore Gas and Electric Company; Calvert Cliffs Nuclear Power
Plant, (Unit Nos. 1 and 2)
Exemption
I
The Baltimore Gas and Electric Company (BGE) is the holder of
Facility Operating License Nos. DPR-53 and DPR-69 for the Calvert
Cliffs Nuclear Power Plant, Unit Nos. 1 and 2 (Calvert Cliffs). The
licenses provide, among other things, that the licensee is subject to
all rules, regulations, and orders of the Commission now or hereafter
in effect.
II
Subsection (a) of 10 CFR 70.24, ``Criticality Accident
Requirements,'' requires that each licensee authorized to possess
special nuclear material shall maintain in each area where such
material is handled, used, or stored, an appropriate criticality
monitoring system. In accordance with Subsection (a)(1) of 10 CFR
70.24, coverage of all such areas at Calvert Cliffs shall be provided
by two criticality detectors. However, exemptions may be requested
pursuant to 10 CFR 70.24(d), provided that the licensee believes that
good cause exists for the exemption.
By letter dated August 19, 1996, as supplemented February 14, 1997,
the licensee requested an exemption from the requirements of 10 CFR
70.24(a). A previous exemption from the provisions of 10 CFR 70.24 for
the storage of special nuclear material, including reactor fuel
assemblies [maximum amount of 2,440 kg of U-235 in uranium enriched to
no more than 3.00 weight percent (w/o)] for Unit 1 and maximum amount
of 2450 Kg of U-235 in uranium enriched to no more than 3.05% was
granted to Baltimore Gas and Electric Company for Calvert Cliffs Unit 1
in NRC Materials License No. SNM-1364 and for Calvert Cliffs Unit 2 in
NRC Materials License No. SNM-1624. The materials licenses were issued
on August 23, 1973, for Unit 1 and May 18, 1976, for Unit 2.
The materials licenses expired upon conversion of the construction
permits to operating licenses, which was July 31, 1974, for Unit 1 and
November 30, 1976, for Unit 2, respectively. The basis for the current
exemption request is the same as for the original request. The licensee
proposes to handle and store unirradiated fuel without having a
criticality monitoring system as required by 10 CFR 70.24.
The basis for the exemption is that inadvertent or accidental
criticality will be precluded, in accordance with General Design
Critrion 62 through compliance with the Calvert Cliffs Technical
Specifications, the geometric spacing of fuel assemblies in the new
fuel storage racks and spent fuel storage pool, and administrative
controls imposed on fuel handling procedures.
Special nuclear material, as nuclear fuel, is stored in the spent
fuel pool, the new fuel storage racks, and the Independent Spent Fuel
Storage Installation. The spent fuel pool is used to store irradiated
fuel under water after its discharge from the reactor, and new fuel
prior to loading into the reactor. The Independent Spent Fuel Storage
Installation utilizes dry canisters to store spent fuel.
Special nuclear material is also present in the form of excore
fission chamber detectors and startup neutron sources. The small
quantity of special nuclear material present in these latter items
precludes an inadvertent criticality.
The spent fuel pool is designed to store the fuel in a geometric
array using a solid neutron absorber that precludes criticality. The
effective neutron multiplication factor, Keff, is maintained
less than or equal to 0.95 by the solid neutron absorber. Although
soluble boron is maintained in the spent fuel pool, no credit is taken
for it in determining Keff.
The new fuel storage racks may be used to receive and store new
fuel in a dry condition upon arrival on site and prior to loading in
the reactor or spent fuel pool. The spacing between new fuel assemblies
in the storage racks is sufficient to maintain the array in a
subcritical condition even under accident conditions assuming the
presence of moderator. The maximum enrichment of 5.0 wt% U-235 for the
new fuel assemblies results in a maximum Keff of 0.89 at a
water density of 1.0 gm/cc (fully flooded), and a Keff of
less than 0.89 for aqueous foam at optimum moderation conditions.
Nuclear fuel is moved between the new fuel storage racks, the
reactor vessel, the refueling pool, and the spent fuel pool to
accommodate refueling operations. In addition, fuel is moved into the
facility and within the reactor vessel, or within the spent fuel pool.
In all cases, fuel movements are procedurally controlled and designed
to preclude conditions involving criticality concerns. These procedural
controls include:
1. Plastic bags or other dust covers placed around new core
components are removed or rendered incapable of holding water prior to
inserting the assemblies into the new fuel storage racks.
2. Only the auxiliary hook of the spent fuel cask handling crane
may be used to move new fuel. Therefore, only one fuel assembly can be
moved at a time.
3. A maximum of two fuel assemblies are permitted outside of the
approved shipping container or new fuel storage rack location at one
time, one of which must be located in the new fuel inspection platform.
Although two highly enriched assemblies may achieve criticality under
close proximity, fully flooded conditions, it is highly improbable that
the required water level for neutron moderation could be attained. The
spent fuel pool area and new fuel handling areas would have to be
flooded to an elevation approximately 17 feet above the floor. Based on
the possible sources of water, achieving this fully flooded condition
would require blockage of floor drains, sealing of access doors, and
numerous procedure violations. In addition, the spent fuel pool high
level alarm would alert operators of flooding from any of these
sources. Since no fire protection sprinkler system exists in the new
fuel handling area, there is no source of low-density aqueous foam
moderation.
Technical Specifications also preclude certain movements over the
spent fuel pool to prevent an inadvertent criticality. Previous
accident analyses have demonstrated that a fuel handling accident
(i.e., a dropped fuel assembly) will not create conditions which could
result in inadvertent criticality. Additionally, the Emergency Response
Plan contains provisions for coping with unusual events such as a
dropped fuel assembly.
In order to meet the requirements of General Design Criterion 63,
three area radiation monitors are provided for detecting high radiation
levels in the spent fuel pool area, the spent fuel handling machine,
and the new fuel storage area. At the alarm setpoint of these monitors,
audible and visual alarms annunciate locally and in the control room.
The output of each monitor is also recorded in the control room.
Based upon the information provided, there is reasonable assurance
that irradiated and unirradiated fuel will remain subcritical during
handling and storage. The circumstances for granting an exemption to 10
CFR 70.24 are met because criticality is precluded with the present
design configuration, Technical
[[Page 40389]]
Specifications requirements, administrative controls, and the fuel
handling equipment and procedures. Therefore, the staff has determined
that the Licensee has demonstrated good cause for the granting of the
exemption, thus the exemption should be granted.
III
Accordingly, the Commission has determined that, pursuant to 10 CFR
70.14, this exemption is authorized by law, will not endanger life or
property or the common defense and security, and is otherwise in the
public interest. Therefore, the Commission hereby grants Baltimore Gas
and Electric Company an exemption as described in Section II above from
10 CFR 70.24, ``Criticality Accident Requirements'' for Calvert Cliffs
Nuclear Power Plant, Unit Nos. 1 and 2.
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 (61 FR 52959).
This exemption is effective upon issuance.
Dated at Rockville, Maryland, this 18th day of July 1997.
For the Nuclear Regulatory Commission.
Samuel J. Collins,
Director, Office of Nuclear Reactor Regulation.
[FR Doc. 97-19802 Filed 7-25-97; 8:45 am]
BILLING CODE 7590-01-U
