ML20149A527
| ML20149A527 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 07/03/1997 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20148U673 | List: |
| References | |
| NUDOCS 9707110214 | |
| Download: ML20149A527 (4) | |
Text
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- y; UNITEC JTATES NUCLEAR REGULATORY COMMISSION WASHINGTf N, D.C. 20066-0001
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SAFETY EVALUATION BY THE DE
- 0F NUCLEAR REACTOR REGULATION l
1 RELATING TO REOUEST FQf, atC U DM FROM 13 CFR 70.24 GPU NUCLE Q i.0 90RATIM i
THREE MILE ISLAND UNIT 1 DOCKET NO. 50-289 j
1.0 INTRODUCTION
i By submittal dated Fegruary 7,1997, as supplemnted March 26 and 1
June 5, 1997, GPU Nuclear Corporation (the lictnsee) requested an Exemption i-from the requirements of subsection (a) of 10 CFR 70.24 "(Criticality Accident Requirements.)" The staff evaluation of this above cited request is i
delineated below.
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2.0 EVALUATION The Code of Federal Regulations at subsection (a) of 10 CFR 70.24, l
" Criticality Accident Requirements," requires that each licensee authorized to j
i possess special nuclear material shall maintain in each area where such j
material is handled, used, or stored, a criticality monitoring system "using gamma-or neutron-sensitive radiation detectors which will energize clearly i
audible alarm signals if accidental criticality occurs." Subsection (a)(2) of i
10 CFR 70.24 specifies the detection, sensitivity, and coverage cepabilities of the monitors required by 10 CFR 70.24(a) for persons licerised pior to 4
December 6, 1974. The specific requirements of Subsection (a)(2' are to
" maintain a monitoring system capable of detecting a criticality waich 7enerates radiation levels of 300 rems per hour one foot from the source of tM radiation."- Subsection (a)(3) of 10 CFR 70.24 requires that the licensee raa'l maintain emergency procedures for each area in which this licensed
- A ial nucleer material is handled, used, or stored and provides (1) that the rrocedures ensure that all personnel withdraw to an area of safety upon the seunding of a criticality monitor alarm, (2) that the procedures must include dri" - t-familiarize personnel with the evacuation plan, and (3) that the 7.n,c.nm..es designate responsible individuals for determining the cause of the Grm and pincoment of radiation survey instruments in accessible locations for use in such an emergency. Subsection (d) of 10 CFR 70.24 states that any licensee who believes that there is good cause why he should be granted an 9707110214 970703
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PDR ADOCK 05000289 P
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l 1 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 exemption requested.
L The purpose of 10 CFR 70.24(a), (a)(?), and (a)(3) is to ensure that any
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inadvertent criticality is detected a W that action is taken to protect personnel and correct the problem. ?;; letter dated February 7, 1997, as j
supplemented March 26, 1997, and June 5, 1997, the licensee requested an i
exemption from the requirements of 10 CFR 70.24(a). The licensee proposes to i
handle and store unirradiated fuel and other special nuclear matarial without j
having either the criticality monitoring system or the emergency procedures specified in 10 CFR 70.24. The licensee believes that procedures and design i
features make an inadvertent criticality unlikely, in accordance with General l
Design Criterion 62.
j Special nuclear material, as nuclear fuel, is stored in the spent fuel pool or the new (unirradiated) fuel storage racks. The spent fuel pool is used to i
store irradiated fuel under water after its discharge from the reactor, and new fuel prior to loading into the reactor. The new fuel racks are used to store new fuel in a dry condition upon arrival on site.
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Special nuclear material is also present in the form of fissile material i
incorporated into nuclear instrumentation. The small quantity of special j
nuclear material present in these items precludes an inadvertent criticality.
Consistent with Technical Specifications (TS) Section 5.4.1, the spent fuel pool is designed to store the fuel in a geometric array that precludes criticality.
The spent fuel racks are designed such that the effective
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neutron multiplication factor, k,,ditions for fuel of maximum enrichment of 5.0 will remain less than or equal to 0.95 undre all normal and accident con l
wt% U-235.
The staff has found this design adequate.
l The new fuel storage racks may be used to receive and store new fuel in a dry 1
condition upon arrival on site and prior to loading in the reactor or spent i
fuel pool. The spacing between new fuel assemblies in the storage racks is l
sufficient to maintain the array in a subcritical condition even under i
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 l
k,,, of less than 0.95 under conditions of accidental flooding by unborated water, and k,ihe staff has found the design of the licensee's new fuel storage less than 0.98 under conditions of low-density optimum i
moderation.
i racks to be adequate to store fuel enriched to no greater than 5.0 wt% U-235.
L Nuclear fuel is moved between the new fuel storage racks, the reactor vessel, 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 i
designed to preclude conditions involving criticality concerns.
Fuel handling
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procedures and the design features of the fuel handling system are discussed in the licensee's Final Safety Analysis Report.
1 Procedures and controls prevent an inadvertent criticality M ir.3 fuel
-handling; nevertheless, radiation monitoring, as required ay General Design j
Criterion 63, is provided for handling new fuel prior te being placed into the
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- spent fuel pool.
In addition, handling of fuel in the spent fuel pool is monitored by TS-required radiation monitors on the fuel handling bridges.
l These required radiation monitors have alarm response procedures which provide j
instructions to the operators upon receipt of alarms.
The licensee conducts training of fuel handling bridge operators and maintenance personnel.
In addition, all individuals who have access to radiologically controlled areas are required to complete initial training, and annual refresher training thereafter, which includes proper response to area i
l radi aton monitor alarms.
The purpose of 10 CFR 70.24 is to ensure that if a criticality were to occur during the handling of special nuclear material, personnel would be alerted to that fact and would take appropriate action. The staff has determined that such an accident is highly unlikely to occur; furthermore, 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 likelyhood of an inadvertent criticality together with the licensee's adherence to General Design Criterion 63 and radiation worker training constitute good cause for granting an exemption to the requirements of 10 CFR l
70.24(a).
3.0 CONCLUSION
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(a) are met because criticality is precluded with the present design configuration, TS requirements, administrative controls, and the fuel handling equipment and procedures. Therefore, the staff concludes that the licensee's request for an exemption from the requirements of 10 CFR 70.24(a) is acceptable and should be i
granted.
Principal Contributor:
L. Kopp Dated:
July 3, 1997
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