[Federal Register Volume 63, Number 29 (Thursday, February 12, 1998)]
[Notices]
[Pages 7186-7188]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-3582]
=======================================================================
-----------------------------------------------------------------------
NUCLEAR REGULATORY COMMISSION
[Docket No. 50-285]
In the Matter of Omaha Public Power District; Fort Calhoun
Station, Unit No. 1; Exemption
I
The Omaha Public Power District (OPPD) is the holder of Facility
Operating License No. DPR-40 for the Fort Calhoun Station, Unit No. 1
(FCS) which authorizes operation of the Fort Calhoun Station, Unit No.
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 one pressurized-water reactor at the
licensee's site located in Washington County, Nebraska.
II
Section 70.24 of Title 10 of the Code of Federal Regulations,
``Criticality Accident Requirements,'' requires that each licensee
authorized to possess special nuclear material (SNM) shall maintain a
criticality accident monitoring system in each area where such material
is handled, used, or stored. Subsections (a)(1) and (a)(2) of 10 CFR
70.24 specify detection and sensitivity requirements that these
monitors must meet. Subsection (a)(1) also specifies that all areas
subject to criticality accident monitoring must be covered by two
detectors. Subsection (a)(3) of 10 CFR 70.24 requires licensees to
maintain emergency procedures for each area in which this licensed SNM
is handled, used, or stored and provides that (1) the procedures ensure
that all personnel withdraw to an area of safety upon the sounding of a
criticality accident monitor alarm, (2) the procedures must include
drills to familiarize personnel with the evacuation plan, and (3) the
procedures designate responsible individuals for determining the cause
of the alarm and placement of radiation survey instruments in
accessible locations for use in such an emergency. Subsection (b)(1) of
10 CFR 70.24 requires licensees to have a means to identify quickly
personnel who have received a dose of 10 rads or more. Subsection
(b)(2) of 10
[[Page 7187]]
CFR 70.24 requires licensees to maintain personnel decontamination
facilities, to maintain arrangements for a physician and other medical
personnel qualified to handle radiation emergencies, and to maintain
arrangements for the transportation of contaminated individuals to
treatment facilities outside the site boundary. Paragraph (c) of 10 CFR
70.24 exempts Part 50 licensees from the requirements of paragraph (b)
of 10 CFR 70.24 for SNM used or to be used in the reactor. Paragraph
(d) of 10 CFR 70.24 states that any licensee who believes that there is
good cause why he should be granted an exemption from all or part of 10
CFR 70.24 may apply to the Commission for such an exemption and shall
specify the reasons for the relief requested.
III
The SNM that could be assembled into a critical mass at FCS is in
the form of nuclear fuel. In addition, the quantity of SNM other than
fuel that is stored on site in any given location is small enough to
preclude achieving a critical mass. As set forth below, the
Commission's technical staff has evaluated the possibility of an
inadvertent criticality of the nuclear fuel at FCS.
By letter dated August 29, 1997, as supplemented by letter dated
October 23, 1997, the licensee requested an exemption from the
requirements of 10 CFR 70.24 in its entirety for FCS. The licensee
proposes to handle and store unirradiated fuel without having a
criticality monitoring system with the sensitivity required by 10 CFR
70.24.
The basis for the staff to determine that inadvertent or accidental
criticality is extremely unlikely can be established through compliance
with the FCS 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.
SNM, as nuclear fuel, is stored in the new fuel storage rack and in
the spent fuel pool. The spent fuel pool is used to store irradiated
fuel under water after its discharge from the reactor and new
(unirradiated) fuel prior to loading into the reactor. New fuel is
stored in the new fuel storage rack in a dry condition.
SNM is also present in the form of excore fission chamber detectors
and startup neutron sources. The small quantity of SNM 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 for fuel
enriched to 4.5 wt% U-235. 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 onsite and prior to loading in the
reactor or spent fuel pool. The spacing between new fuel assemblies and
the solid neutron absorbers in the storage racks is sufficient to
maintain the dry array in a subcritical condition. The new fuel storage
rack is located at an elevation of 18.75 feet above the main floor
which provides adequate drainage and precludes flooding. Because no
fire protection sprinkler system exists in this area, there is no
source of low-density aqueous foam optimum moderation. The current
approved maximum enrichment of 4.5 wt% U-235 for the new fuel
assemblies results in a maximum keff of less than 0.90 under
dry conditions.
Nuclear fuel is moved between the NRC-approved shipping containers,
the new fuel storage racks, the reactor vessel, and the spent fuel pool
to accommodate refueling operations. In all cases, fuel movements are
procedurally controlled and designed to preclude conditions involving
criticality concerns. For example, during new fuel receipt inspection,
FCS fuel handling procedures allow a maximum of two fuel assemblies to
be in the inspection stands in the receipt area (out of the shipping
container and not in the new fuel storage rack). However, when
installed in the inspection stands, both assemblies have an edge-to-
edge separation distance in excess of 14 feet. This geometric spacing
is well in excess of that maintained by the NRC-approved shipping
container (approximately 3 inches). There are no sprinklers in the new
fuel receipt/storage room and the use of fire fighting equipment is
very unlikely since there are no combustible materials permanently
stored in this room. Even if fire suppression water were introduced
into the room, sufficient drainage exists to preclude potential
moderation of new fuel assemblies. Therefore, because of the large
physical separation of new fuel assemblies and the extremely unlikely
event of any potential moderation, there is sufficient assurance that
keff remains less than 0.95, thus precluding criticality.
FCS was licensed to the 70 General Design Criteria for Nuclear
Power Plant Construction published as drafts in the Federal Register
(32 FR 10213) on July 11, 1967. Draft Criterion 18, Monitoring Fuel and
Waste Storage, was met. As noted in Section 11.2.3 and Appendix G of
the FCS Updated Safety Analysis Report, area monitoring of dose rates
is supplied in the containment and auxiliary buildings, including the
fuel storage areas. Local and control room alarms and indicators (not
necessarily meeting the 10 CFR 70.24 sensitivity requirements) are
provided to alert personnel to take appropriate action in the unlikely
event of excessive radiation levels due to accidental criticality.
The purpose of the criticality monitors required by 10 CFR 70.24 is
to ensure that if a criticality were to occur during the handling of
SNM, personnel would be alerted to that fact and would take appropriate
action. In view of the above information, the staff has determined that
it is extremely unlikely for an inadvertent criticality to occur in SNM
handling or storage areas at FCS. Criticality is precluded with the
present design configuration, Technical Specification requirements,
administrative controls, and the fuel handling equipment and
procedures. In addition, as described above, the licensee has radiation
monitors, as required by General Design Criterion 63, in fuel storage
and handling areas. These monitors will alert personnel to excessive
radiation levels and allow them to initiate appropriate safety actions.
The low probability of an inadvertent criticality, together with the
licensee's adherence to General Design Criterion 63, constitutes good
cause for granting an exemption to the requirements of 10 CFR 70.24.
IV
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 Omaha Public
Power District an exemption as described in Section II above from 10
CFR 70.24, ``Criticality Accident Requirements'' for the Fort Calhoun
Station.
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 (63 FR 5821).
This exemption is effective upon issuance.
For the Nuclear Regulatory Commission.
[[Page 7188]]
Dated at Rockville, Maryland, this 6th day of February 1998.
Frank J. Miraglia, Jr.,
Acting Director, Office of Nuclear Reactor Regulation.
[FR Doc. 98-3582 Filed 2-11-98; 8:45 am]
BILLING CODE 7590-01-P