ML20149H342
| ML20149H342 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 07/18/1997 |
| From: | Collins S NRC (Affiliation Not Assigned) |
| To: | BALTIMORE GAS & ELECTRIC CO. |
| Shared Package | |
| ML20149H345 | List: |
| References | |
| NUDOCS 9707240346 | |
| Download: ML20149H342 (6) | |
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UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION i
i In the Matter of
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Baltimore Gas and Electric Company
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Docket Nos. 50-317 and 50-318
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Calvert Cliffs Nuclear Power Plant,
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Unit _Nos. I and 2)
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i EXEMPTION l
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. I and 2 (Calvert Cliffs). The licenses provide, among other
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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 i
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 i
9707240346 970718 PDR ADOCK 05000317 P
r i t 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 I and maximum amount of 2450 Kg of U-235 in uranium enriched l
to no more than 3.05% was granted to Baltimore Gas and Electric Company for j
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 I and May 18, 1976, for Unit 2.
l The materials licenses expired upon conversion of the construction l
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permits to operating licenses, which was July 31, 1974, for Unit I and d
l 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.
j 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
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-3 chamber detectors and startup neutron sources. The small quantity of special nuclear material present in these latter items precludes an inadvertent
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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, K.,,, 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 K,,,.
l The new fuel storage racks may be used to receive and store new fuel in j
a dry condition upon arrival on site and prior to loading in the reactor or i
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 1
i accident conditions assuming the presence of moderator. Thc maximum 3
i enrichment of 5.0 wt% U-235 for the new fuel assemblies results in a maximum l
K,,, of 0.89 at a water density of 1.0 gm/cc (fully flooded), and a K,, of I
less than 0.89 for aqueous foam at optimum moderation conditions.
I Nuclear fuel is moved between the new fuel storage racks, the reactor 4
I vessel, the refueling' pool, and the spent fuel pool to accommodate refueling operations.
In addition, fuel is moved into the facility and within the i
reactor vessel, or within the spent fuel pool.
In all cases, fuel movements i
are procedurally controlled and designed to preclude conditions involving j.
criticality concerns.
These procedural controls include:
1.
Plastic bags or other dust covers placed around new core components
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are removed or rendered incapable of holding water prior to inserting the assemblies into the new fuel storage racks.
j 2.
Only the auxiliary hook of the spent fuel cask handling crane may be 1
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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
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i 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 i
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
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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 alm preclude certain movements over the spent 1
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 Plar, 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 suberitical during handling and storage. The circumstances for granting an exemption to 10 CFR 70.24 are met 1
because criticality is precluded with the present design configuration,
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Technical Specifications requirements, administrative controls, and the fuel l
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 i
Accident Requirements" for Calvert Cliffs Nuclear Power Plant, Unit Nos.
I 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 cuality of I
the' human environment (61 FR 52959).
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- r This' exemption is effective upon issuance.
i FOR THE NUCLEAR REGULATORY COMMISSION a
s7 Director i
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Office of Nuclear Reactor Regulation Dated at Rockville, Maryland,
- this jBtWay of July.
1997.
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