ML20141A075
| ML20141A075 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 05/07/1997 |
| From: | Richard Anderson NORTHERN STATES POWER CO. |
| To: | |
| Shared Package | |
| ML20141A029 | List: |
| References | |
| NUDOCS 9705140149 | |
| Download: ML20141A075 (16) | |
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UNITED STATES NUCLEAR REGULATORY COMMISSION NORTHERN STATES POWER COMPANY PRAIRIE ISLAND NUCLEAR GENERATING PLANT DOCKET Nos. 50-282 50-306 REQUEST FOR AMENDMENT TO OPERATING LICENSES DPR-42 & DPR-60 LICENSE AMENDMENT REQUEST DATED May 7,1997 Amendment of Spent Fuel Pool Special Ventilation System Specifications Northern States Power Company, a Minnesota corporation, requests authorization for changes to the Prairie Island Operating License, Appendix A as shown in the attachments labeled Exhibits A, B, and C. Exhibit A describes the proposed changes, reasons for the changes, and the supporting safety evaluation and significant hazards determination. Exhibit B contains current Prairie Island Technical Specification pages marked up to show the proposed changes. Exhibit C contains the revised Technical Specification pages incorporating the proposed changes.
This letter and its attachments contain no restricted or other defense information.
NORI ERN STATE POWER COMPANY By sc/$ w~
R'oge'r O. Anderson Director, Licensing and Management issues On this 7 day of MAy [9f7 before me a notary public in and for said County, persondfly appeared, Roger O. Anderson, Dhector, Licensing and Management issues, and being first duly sworn acknowledged that he is authorized to execute this document on behalf of Northern States Power Company, that he knows the contents thereof, and that to the best of his knowledge, information, and belief the statements made in it are true and that it is not inter-posed for delay.
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, DALE M. VINCENT
, befAAT PUDUC. Mast 5014 DAKoTACOUNTY
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- Mr Commeste hohes JuL M.
9705140149 9705d7 '~
PDR ADOCK 05000202 P PDR__
4 LICENSE AMENDMENT REQUEST DATED May 7,1997 Amendment of Spent Fuel Pool Special Ventilation System Specifications EXHIBIT A Description of the Proposed Changes, The Reasons for Requesting the Changes, and the Supporting Safety Evaluation /Significant Hazards Determination Pursuant to 10 CFR Part 50, Sections 50.59 and 50.90, the holders of Operating Licenses DPR-42 and DPR-60 hereby propose the following changes to the Facility Operating Licenses and Appendix A, Technical Specifications:
BACKGROUND This license amendment request proposes to revise Prairie Island Technical Specification 3.8.D which prescribes the limiting conditions for operability for the spent fuel pool special ventilation system. Literal compliance with this specification as written could preclude movement of any loads through the spent fuel pool enclosure. This proposed license amendment will eliminate confusion with respect to the applicability of this specification by removing crane operating limitations and conforming it to the guidance of NUREG-1431, " Standard Technical Specifications, Westinghouse Plants,"
the improved Standard Technical Specifications. ;
I Spent Fuel Pool Enclosure l
The spent fuel pool enclosure is located between the containments for Prairie Island Units 1 and 2. The fuel pool enclosure is a Class I reinforced concrete building with 12 !
to 18 inch thick walls and roof, which is integrally connected to the fuel pool structure.
The fuel pool enclosure covers the new fuel pit and both spent fuel storage pools, and is completely contained within the auxiliary building. Attached for reader convenience are Figures 1 and 2 which show the layout of the spent fuel pool enclosure relative to l the new fuel storage pit, the spent fuel pools, the transfer canal, the fuel handling crane l and the auxiliary building crane. The spent fuel storage pool system includes Spent I Fuel Pool 1 which is the small pool in the center of the enclosure under the slot doors and Spent Fuel Pool 2 which is the large pool at the east end of the enclosure.
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Figure 1 shows the auxiliary building crane moving a load into the spent fuel pool enclosure. In order for the auxiliary building crane to move loads into the spent fuel pool enclosure or to move loads to the auxiliary building cer tral court, north of the spent fuel pool enclosure, the large access doors and the roof slot doors of the spent fuel pool enclosure must be open.
Spent Fuel Pool Special Ventilation System The spent fuel pool special ventilation system is designed to provide ventilation of the spent fuel pool enclosure in the event that high radiation is detected. This is a safeguards system with two complete trains each capable of meeting the design requirements. The minimum flow requirements of this system were sized to maintain a negative pressure in the spent fuel pool enclosure. Attached as Figure 3 for reader convenience is a reduced size copy of Updated Safety Analysis Report (USAR) Figure 5.2-10 which shows the simplified system flow diagram. This figure is typical of each train of the spent fuel pool special ventilation system. One train takes suction from the spent fuel pool enclosure and is filtered by the Unit 1 containment inservice purge system. The other train also takes suction from the spent fuel pool enclosure and is filtered by the Unit 2 containment inservice purge system.
The completely enclosed spent fuel pool area is normally ventilated and exhausted through the normal ventilation system which includes roughing and HEPA filters. In the event of high radiation in the pool area, signals from radiation monitors in the normal ;
ventilation exhaust duct isolate and shut down the normal ventilation system and initiate the spent fuel pool special ventilation system. Ventilation is then accomplished via the spent fuel pool special ventilation system which shares the exhaust portion of the containment in-service purge system. The sir flow is then directed through ;
redundant roughing, HEPA, and charcoal filters in this system.
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Licensina Backaround i Prior to License Amendments 91/84, Specification 3.8.D stated:
From and after the date that one train of the Spent Fuel Pool Special Ventilation System is made or found inoperable for any reason, fuel handling operations are permissible only during the succeeding seven days (unless such train is made operable) provided that the redundant train is verified to be operable daily.
The original specification did not limit or in any manner apply to crane operations other l than fuel handling operations. On March 17,1986, NSP submitted a license amendment request which resulted in NRC issuance of License Amendments 91/84.
The March 1986 license amendment request revised this specification to conform with the guidance of the Standard Technical Specifications in effect at the time of the l 2
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, l submittal which is the extant Prairie Island specification. The Standard Technical j Specifications in effect at that time included provisions for limiting crane operations with loads over spent fuel when the spent fuel pool special ventilation system is inoperable which were thus incorporated into the Prairie Island Technical Specifications. There were no plant conditions, issues or physical changes which necessitated these additional limitations. l The NRC has approved spent fuel storage in Spent Fuel Pool 1 for durations other than temporary core off load storage. This means that spent fuel may be normally stored in Pool 1. Any loads which are required in the Auxiliary Building central court area and are too large to be moved over the spent fuel pool enclosure have to be moved through the spent fuel pool enclosure and over Pool 1 which could include loads over spent fuel depending on where the spent fuel is stored in this pool.
Since issuance of License Amendments 91/84 there have been plant changes which relate to this specification.
In 1992 NSP received approval to handle spent fuel storage casks in Spent Fuel Pool 1 while it contains irradiated fuel. In support of that approval, NSP installed a single- ;
failure-proof auxiliary building crane which meets the design criteria of NUREG-0612, !
" Control of Heavy Loads at Nuclear Power Plants" Prairie Island has also upgraded the i west hoist on the spent fuel pool bridge crane to meet the design criteria of NUREG- !
0612. NSP, through this submittal as identified in italics in the cover letter, is committed I to handle heavy loads over the spent fuel pool in a manner which complies with the requirements of NUREG-0612 and thereby assures that the potential for a load drop is extremely small or the evaluation criteria are satisfied. There are two methods by which Prairie Island provides this assurance: 1) Heavy loads are handled by a single-failure-proof crane with rigging and procedures which implement Prairie Island commitments to NUREG-0612; or 2) spent fuel pool protective covers, for loads up to their design limit, are installed to prevent dropped loads from falling into the spent fuel pool. Installation and use of spent fuel pool protective covers were approved by the NRC in conjunction with the spent fuel pool reracking projects. As discussed in USAR Section 10.2.1, these covers are designed to prevent loads up to 24,800 pounds from i falling into the spent fuel pool when dropped from 6 inches above the cover deck. I installation and use of these spent fuel pool protective covers are governed by plant l procedures which implement NRC approved methodologies. Plant procedures require the use of the spent fuel pool protective covers or use of the single-failure-crane for loads less than 24,800 pounds (the cover design limit). For loads above 24,800 pounds, plant procedures require use of the single-failure-proof crane. Since the ;
potential for a heavy load drop over irradiated fuel is extremely small or the dropped l load is prevented from falling into the spent fuel pool, technical specifications placing limitations on handling loads in the spent fuel pool enclosure are unnecessary.
NSP has determined through testing that when doors into the spent fuel pool enclosure are opened, the spent fuel pool special ventilation system is unable to develop a 3
negative pressure within the enclosure and therefore both trains of the spent fuel pool special ventilation system are inoperable. In order to move loads into the spent fuel pool enclosure or into the auxiliary building central court area through the spent fuel pool enclosure, the enclosure roof slot doors and the large north and south access doors are required to be opened. Therefore, when loads are handled by the auxiliary building crane in the spent fuel pool enclosure, both trains of the spent fuel pool special ventilation system are inoperable.
This license amendment request proposes to amend the Technical Specifications to require spent fuel pool special ventilation system operability only during movement of irradiated fuel as the specification was originally intended.
PROPOSED CHANGES AND REASONS FOR CHANGES The proposed changes to Prairie Island Operating License Appendix A, Technical Specifications, are described below, and the specific wording changes are shown in Exhibits B and C.
- 1. Technical Specification 3.8. REFUELING AND FUEL HANDLING. Applicability and Objectives: Delete "and crane operations in the spent fuel pool enclosure" from the Applicability and delete "and crane operations" from the Objectives.
Justification: These proposed changes will remove crane operating limitations from the fuel handling Technical Specifications in that TS 3.8 would no longer deal with crane operations in the spent fuel pool enclosure. Prairie Island has other cranes which are capable of handling heavy loads in the vicinity of safeguards equipment or irradiated fuel. These other cranes are not the subject of Technical Specifications but are controlled through commitment to NUREG-0612 and implementing plant procedures. The plant operating procedures are controlled under a 10 CFR 50.59 review process. This change to the Technical Specifications will make plant load handling requirements consistent throughout the plant, including crane operations in other areas of the plant including containment.
Also some cranes have been physically modified in accordance with the requirements of NUREG-0612 to further assure safe handling of loads. In particular, the auxiliary building crane and spent fuel pool bridge crane west hoist have been modified to meet NUREG-0612 requirements for single-failure-proof-cranes.
Spent fuel pool protective covers may be installed prior to handling heavy loads, up to the protective cover design limits of 24,800 pounds, to prevent loads from dropping into the spent fuel pool. Plant procedures dictate that for loads up to 4
the design limit either the covers or single-failure-proof crane may be used. For loads weighing more than the cover design limit, use of the single-failure-proof auxiliary building crane is required.
The current Technical Specifications for spent fuel pool special ventilation system operability are not required to assure that crane operations in the fuel pool enclosure are safe because heavy loads are handled by cranes, rigging and procedures which implement the commitments of NUREG-0612 or protective covers are installed over the spent fuel pool. As discussed above, the spent fuel pool special ventilation system is not operable when the auxiliary building crane is carrying loads in the spent fuel pool enclosure.
These proposed changes are consistent with the guidance of NUREG-1431.
- 2. Technical Specification 3.8.D. Spent Fuel Pool Special Ventilation System. :
I Paraaraoh 1: Insert "during movement of irradiated fuel assemblies in the spent fuel pool enclosure" and delete "at all times". I Justification: These changes will require the spent fuel pool special ventilation system to be operable only when irradiated fuel assemblies are moved within the !
spent fuel pool enclosure. The Prairie Island design basis fuel handling accident I analyses, which assume that all fuel rods in one fuel assembly fail due to the drop of one fuel assembly directly onto another fuel assembly, take credit for ,
operation of the spent fuel pool special ventilation system. Thus the spent fuel l pool special ventilation system is required to be operable only during movement of irradiated fuel to maintain the plant within the design basis assumptions.
Movement of heavy loads within the spent fuel pool enclosure are governed by the Prairie Island USAR, NSP commitments to NUREG-0612 and plant implementing procedures. These procedures in combination with physical upgrades of the auxiliary building crane and spent fuel pool bridge crane west hoist assure that radiological releases due to load movements will not occur.
Requiring the spent fuel pool special ventilation system to be operable at all times is not consistent with the system design since this system is not operable l when the auxiliary building crane is used to move loads into the spent fuel pool enclosure due to the need to open the enclosure roof slot doors. These changes are consistent with the guidance of NUREG-1431.
- 3. Technical Specification 3.8.D. Spent Fuel Pool Special Ventilation System.
Paraaraoh 2: Delete requirements relating to crane operations and demonstration of redundant train operability. Add requirements to restore an inoperable train within 7 days, place the operable train in service or suspend movement of irradiated fuel.
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l l Justification: These changes provide a logical succession of events if one train ;
- . of spent fuel pool special ventilation system is inoperable. If one train of spent l
, fuel pool special ventilation system is inoperable this proposed specification J l would allow movement of irradiated fuel to continue for seven days which is :
i consistent with the current Technical Specifications.; During this period, the remaining operable train is adequate to perform the special ventilation system - i function while efforts are made to restore the inoperable train to operable status. ;
This seven day completion time is acceptable due to the fully redundant spent )
fuel pool special ventilation system train and the low probability of a fuel i handling accident during this time. If the time for restoration or irradiated fuel )
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. movement extends beyond 7 days then the redundant spent fuel pool special ventilation system train is operated to assure that it is operable, the. no :
undetected failures preventing system operation will occur, and that any active ,
failure will be readily detected. An alternative to placing the redundant spent fuel ]
- pool special ventilation system train in service is suspending movement of !
2 Irradiated fuel assemblies which precludes a fuel handling accident. These changes are consistent with the guidance of NUREG-1431.
! Provisions of this specification relating to crane cperations are removed for the l same reasons as presented above, that is, use of spent fuel pool protective l covers prevent dropped loads from falling into the spent fuel pool, or use of i cranes upgraded to NUREG-0612 single-failure-proof specifications assures that the potential for a load drop is extremely small. Furthermore, both trains of spent fuel pool special ventilation system are inoperable when the auxiliary building i crane is used for movement of loads within the spent fuel pool enclosure.
- This proposed specification would also remove the requirement for
. demonstrating operability of the redundant train prior to resumption of fuel handling operations. This is acceptable since there is a low probability of a fuel l handling accident during this 7 day period and there is a low probability of failure of the redundant spent fuel pool special ventilation system train since each train is operated monthly. Also, within 30 days prior to handling irradiated fuel, each spent fuel pool special ventilation system train is actuated by a test radiation source. These changes are consistent with the guidance of NUREG-1431.
This proposed change to the current Technical Specification 3.8.D.2 also would allow, after one train were inoperable for seven days, continuous operation of the other train of the spent fuel pool special ventilation system for an extended j period of time in lieu of restoring the inoperable train to an operable status. Such l an occurrence is unlikely since handling of irradiated fuel rarely continues for !
extended periods of time and NSP as a matter of practice does not operate with safeguards trains inoperable for extended periods of time even though allowed ,
by the Technical Specifications. In the unlikely event a spent fuel pool special l
- ventilation train were operated for an extended period of time, the performance !
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- capability of the system is assured through the requirements of current Technical Specification 4.14. After 720 hours0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br /> of operation, in accordance with TS.4.15.8.1, the spent fuel pool special ventilation system would be declared inoperable to allow required surveillance testing to be performed.
- 4. Technical Specification 3.8.D. Spent Fuel Pool Special Ventilation System.
Paraaraoh 3: Revise " fuel handling operations" to " movement of irradiated fuel assemblies" and delete " crane operations with loads over spent fuel".
Justification: These changes are proposed for the same reasons given above for item 3.
- 5. Bases 3.8. Paae B.3.8-2: Add a statement which clarifies that the spent fuel pool enclosure doors are required to be closed when the spent fuel pool special ventilation system is required to be operable. Clarification is also included that personnel access is allowed.
Justification: NSP has determined through testing that the spent fuel pool special ventilation system is unable to develop a negative pressure in the spent fuel pool enclosure when doors into the enclosure are open. Thus, the doors into the spent fuel pool enclosure must be closed as a condition for spent fuel pool special ventilation system operability. Opening of personnel doors for personnel use is acceptable, since the system will readily establish a negative pressure following spring closure of the door if an event occurs and the system is required to be operating. As stated in the proposed Bases, blocking of doors open is not permitted.
SAFETY EVALUATION The proposed changes to TS 3.8 will require the spent fuel pool special ventilation system to be operable during irradiated fuel movement. Current Technical Specification limitations on crane operations inside the spent fuel pool enclosure have been removed. These changes will maintain the plant in a safe condition because:
. The spent fuel pool special ventilation system will continue to mitigate the plant design basis fuel handling accident.
. Heavy loads are handled by cranes which have been upgraded to meet the requirements of NUREG-0612 and in accordance with plant procedures which implement the requirements of NUREG-0612, or the heavy loads are handled over spent fuel pool protective covers, in accordance with prescribed procedures, which prevent dropped loads from falling into the spent fuel pool.
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Spent Fuel Pool Special Ventilation System Desian Basis The spent fuel pool special ventilation system provides absolute and charcoal filtration of effluents from the spent fuel pool enclosure following a fuel handling accident. The spent fuel pool special ventilation system design basis is established by the consequences of the limiting design basis fuel handling accident. The design basis fuel handling accident assumes that an irradiated fuel assembly is dropped directly on another irradiated fuel assembly. Analyses of this accident showed that the resulting buckling loads on the fuel rods would be below the critical buckling loads and the cladding stresses would be below the yield stress.
For the purposes of evaluating the environmental consequences of a fuel handling accident, a conservative upper limit of damage is assumed by considering the cladding rupture of all rods in one complete assembly. The remaining fuel assemblies are protected by the storage rack structure within which the fuel assemblies are stored such that no lateral bending loads would be imposed which would cause cladding failure.
The analysis of the design basis feel handling accident assumed that only one train of the spent fuel pool special ventilation system is functional due to a single failure that disables the other train. The accident analysis accounts for the reduction in airborne radioactive material provided by one remaining train of this filtration system. Using assumptions provided in Safety Guide 25, the resulting site boundary doses are well within the limits of 10 CFR Part 100.
Thus, Technical Specifications which require the spent fuel pool special ventilation system to be operable during movement of irradiated fuel is consistent with the design basis of the plant and continues to protect the health and safety of the public. !
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Loads which weigh more tnan a fuel assembly with its attached tool are the subject of !
NUREG-0612 which prescribes crane design requirements, rigging specifications and !
administrative controls for handling of heavy loads. When heavy loads are handled within the spent fuel pool enclosure: 1) single-failure-proof cranes are used with rigging and procedures which implement Prairie Island commitments to NUREG-0612; or 2) l spent fuel pool protective covers with their implementing procedures in accordance with Prairie Island's USAR and NUREG-0612 commitments.
- 1) In accordance with commitments to NUREG-0612, Prairie Island modified the auxiliary building crane main hoist and the spent fuel pool bridge crane west hoist to satisfy single-failure-proof criteria. Handling of heavy loads in accordance with the l l
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c procedure requirements, rigging and single-failure-proof crane criteria eliminates the need to analyze the effects of drops of heavy loads in accordance with the evaluation criteria of Section 5.1 of NUREG-0612. Since the effects of ioad drops are not considered, there is no need for the spent fuel pool special ventilation system to be operable since there are no radiological releases to be filtered. Therefore, the proposed Technical Specification changes which remove crane load handling limitations from consideration in conjunction with spent fuel pool special ventilation system operability are acceptable.
- 2) In support of Prairie Island's spent fuel pool reracking modifications, NSP obtained NRC approval to use protective covers over the spent fuel pools containing irradiated fuel. Installation and use of these covers are governed by plant operating procedures which implement NRC commitments for their use. Heavy loads are prevented from falling into the spent fuel pool by these covers when loads are handled in accordance with the prescribed procedures. Since these covers with their implementing procedures prevent dropped loads from falling into the spent fuel pool, there is no need for the spent fuel pool special ventilation system to be operable since there are no radiological releases to be filtered. Therefore, the proposed Technical Specification changes which ;
remove .~ane load handling limitations from consideration in conjunction with spent fuel l pool special ventilation system operability are acceptable.
Safety Evaluation Conclusions This proposed Technical Specification change will remove crane load handling limitations from the Specifications which govern spent fuel pool special ventilation system operability.
Under the proposed Technical Specifications the spent fuel pool special ventilation ;
system will be operable during handling of irradiated fuel and therefore will be available to mitigate the consequences of a fuel handling accident as originally intended. i l
Heavy loads in the spent fuel pool enclosure are handled in a manner which prevents dropping loads or prevents dropped loads from falling into the spent fuel pool. Use of plant procedures, rigging and cranes which satisfy the requirements of NUREG-0612 assures that the potential for dropping a heavy load is extremely small and therefare, in accordance with the commitments to NUREG-0612, the effects of drops of these loads are not considered. Use of spent fuel pool covers in accordance with methodology previously approved by the NRC, prevents dropped loads from falling into the spent fuel pools and therefore the effects of drops of these loads onto irradiated fuel are not considered.
Therefore, the health and safety of the public will not be adversely affected by these proposed Technical Specification changes.
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l DETERMINATION OF SIGNIFICANT HAZARDS CONSIDERATIONS The proposed changes to the Operating License have been evaluated to determine whether they constitute a significant hazards consideration as required by 10 CFR Part 50, Section 50.91 using the standards provided in Section 50.92. This analysis is provided below:
- 1. The proposed amendment will not involve a significant increase in the probability or consequences of an accident previously evaluated.
Operation of the Prairie Island plant in accordance with the proposed changes does not involve a significant increase in the probability or consequences of an accident previously evaluated. The proposed changes do not involve a physical modification to the plant.
1 The spent fuel pool special ventilation system is provided to mitigate the consequences of a design basis fuel handling accident which involves dropping l a spent fuel assembly directly onto a stored spent fuel assembly. Spent fuel pool !
special ventilation system performance and environmental consequences were I based on the conservative assumption that all fuel rods in one fuel assembly fail. l However, evaluation of the mechanical performance of spent fuel stored in the spent fuel racks demonstrated that no fuel rods fail. l l
The proposed changes will continue to require the spent fuel pool special l ventilation system to be operable to mitigate the consequences of a fuel handling accident in accordance with its original design intent. Spent fuel pool special ventilation system operability is not required in conjunction with crane operations. Heavy loads in the spent fuel pool enclosure are handled 1) by single-failure-proof cranes with rigging and plant procedures which implement Prairie Island commitments to NUREG-0612 or 2) over spent fuel pool protective covers as described in the Prairie Island USAR. In accordance with the ,
requirements of NUREG-0612, use of a single-failure-proof crane with rigging ,
and procedures which implement the requirements of NUREG-0612 assures that the potential for a load drop is extremely small and the effects of heavy load !
drops are not considered. Spent fuel pool covers prevent dropped loads from falling into the spent fuel pool. Thus, there are no radiological releases resulting from handling heavy loads in the spent fuel pool enclosure for which spent fuel pool special ventilation system operability would be required. Therefore, these l changes do not involve a significant increase in the probability or consequences of the fuel handling accident previously evaluated.
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- 2. The proposed amendment will not create the possibility of a new or different kind of accident from any accident previously analyzed.
The proposed Technical Specification changes continue to require the spent fuel pool special ventilation system to be operable during handling of irradiated fuel as originally designed. Heavy loads in the spent fuel pool enclosure are handled by means which assure that the potential for a dropped load is extremely small (through use of single-failure-proof cranes with rigging and plant procedures which implement Prairie Island commitments to NUREG-0612) or prevent dropped loads from falling into the spent fuel pool (through use of spent fuel pool protective covers as described in the USAR). Thus, the proposed changes do not create the possibility of a new or different kind of accident from any accident previously evaluated because the proposed changes, in themselves, do not introduce a new mode of plant operation, surveillance requirement or involve a physical modification to the plant.
The proposed changes do not alter the design, function, or operation of any plant components and therefore, no new accident scenarios are created.
Therefore, the possibility of a new or different kind of accident from any accident previously evaluated would not be created by these amendments.
- 3. The proposed amendment will not involve a significant reduction in the margin of safety.
The proposed amendment will continue to require the spent fuel pool special ventilation system to operate following a fuel handling accident as originally designed. Heavy load crane operations in the spent fuel pool enclosure are handled 1) by single-failure-proof cranes with rigging and plant procedures which implement Prairie Island commitments to NUREG-0612; or 2) over spent fuel pool protective covers as described in the Prairie Island USAR. Provision of single-failure-proof equipment and compliance with the other requirements of NUREG-0612 provides an equivalent margin of safety to that which would be demonstrated by analysis of the radiological effects of dropped loads. Use of protective covers has been previously reviewed and approved by the NRC.
Therefore, this proposed amendment does not involve a significant reduction in the margin of safety .
Based on the evaluation described above, and pursuant to 10 CFR Part 50, Section 50.91, Northern States Power Company has determined that operation of the Prairie Island Nuclear Generating Plant in accordance with the proposed license amendment request does not involve a significant hazards considerations as defined by Nuclear Regulatory Commission regulations in 10 CFR part 50, Section 50.92.
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O ENVIRONMENTAL ASSESSMENT Northern States Power Company has evaluated the proposed changes and determined that: ;
- 1. The changes do not involve a significant hazards consideration, or
- 2. The changes do not involve a significant change in the types or significant increase in the amounts of any effluents that may be released offsite, or
- 3. The changes do not involve a significant increase in individual or cumulative oc upational radiation exposure.
Accordingly, the proposed changes meet the eligibility criterion for categorical exclusion set forth in 10 CFR Part 51, Section 51.22(c)(9). Therefore, pursuant to 10 CFR Part 51, Section 51.22(b), an environmental assessment of the proposed changes is not required.
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