ML20202E402

Forwards Draft RAI Re Proposed Amend on SFP Assemblies Storage Expansion.Memo & Encl Do Not Convey Formal Request for Info or Represent NRC Position

ML20202E402
Person / Time
Site:	Vermont Yankee File:NorthStar Vermont Yankee icon.png
Issue date:	01/28/1999
From:	Croteau R NRC (Affiliation Not Assigned)
To:	NRC (Affiliation Not Assigned)
References
TAC-MA3490, NUDOCS 9902030009
Download: ML20202E402 (3)

Text

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January 28, 1999 1

MEMORANDUM TO: Docket File 1 .

FROM: Richard Croteau, Project Manager /s/ l Project Directorate 12  :

Division of Reactor Projects - 1/11 i Office of Nuclear Reactor Regulation l

SUBJECT:

VERMONT YANKEE NUCLEAR POWER STATION, DRAFT REQUEST 1 FOR ADDITIONALINFORMATION, PROPOSED AMENDMENT i REGARDING SPENT FUEL POOL ASSEMBLIES STORAGE ,

EXPANSION, TAC NO. MA3490 '

The attached request for additional information (RAI) was transmitted by electronic mail i on January 27,1999, to Mr. T. Silko of Vermont Yankee Nuclear Power Corporation. Review of the RAI would allow the licensee to determine and agree upon a schedule to respond to the RAI. This memorandum and the attachment do not convey a formal request for information or represent an NRC staff position.

Docket No. 50-271

Attachment:

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MEMORANDUM TO: Docket File  !

l FROM: Richard Croteau, Project Manager Project Directorate 1-2 .

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j Division of Reactor Projects - 1/ll /  !

Office of Nuclear Reactor Regulation , I i'  !

SUBJECT:

VERMONT YANKEE NUCLEAR POWER STATION, DRAFT REQUEST  !

FOR ADDITIONAL INFORMATION, PROPOSED AMENDMENT  !

REGARDING SPENT FUEL POOL ASSEMBLIES STORAGE  !

EXPANSION, TAC NO. MA3490 I t

The attached request for additional information (RAI) was transmitted by electronic mail l on January 27,1999, to Mr. T. Silko of Vermont Yankee Nuclear Power Corporation. Review of  !

4 the RAI would allow the licensee to determine and agree upon a schedule to respond to the  !

RAl. This memorandum and the attachment do not convey a formal request for information or  :

represent an NRC staff position.  !

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Docket No. 50-271 t

Attachment:

As stated  ;

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j DRAFT n l ATTACHMENT REQUEST FOR ADDITIONAL INFORMATION  !

BY THE OFFICE OF NUCLEAR REACTOR REGULATION DIVISION OF SYSTEMS SAFETY AND ANALYSIS PLANT SYSTEMS BRANCH REGARDING SPENT FUEL STORAGE EXPANSION  ;

VERMONT YANKEE NUCLEAR POWER STATION DOCKET NO. 50-271 l

l

1. In Tables 5.8.1 and 5.8.2 of the submittal, the licensee provides the heat loads from the partial- and full-core offload scenarios and the heat rejection rates for several means of cooling. Please provide the equilibrium bulk water temperatures for the heat load scenarios to demonstrate that it remains below the design-basis temperature of 150 *F.

2. Provide the heat exchanger effectiveness and the parameter values (e.g., flow rates and temperatures) used to determine the effectiveness for the design cases with one and two pump operation for the normal and standby fuel pool cooling subsystems.

3. In Section 5.8.3 of the submittal, the licensee calculates the time for boiling to occur.

Please provide the maximum boiloff rate. Also provide the makeup sources and the flow rates available for corrective actions.

4. Explain the scenario that would occur for an emergency full-core offload and demonstrate that sufficient cooling capacity exists to prevent bulk boiling of the coolant for a bounding (full spent fuel pool) case. For example, the standard review plan states that the cooling capacity should be sufficient to remove the decay heat from one full core after 6 days of operation and 144 hours0.00167 days <br />0.04 hours <br />2.380952e-4 weeks <br />5.4792e-5 months <br /> of decay following a normal 30-day l refueling outage. A single failure need not be considered.

5. In final safety analysis report (FSAR) Table 10.5.2, the normal refueling load is estimated to be 136 assemblies. As listed in Table 1.1 of the submittal, the licensee used refueling loads of 96 - 108 assemblies for 1999 and beyond to determine the bounding heat load. Explain the change in the design-basis heat load between the proposed offload schedule and the FSAR discharge estimate with regards to ensuring the design-basis heat load is not exceeded.

6. In the submittal, the bounding heat load is calculated after six and ten days of decay time in the FSAR, the licensee states that fuel movement is not restricted to the predicted heat levels for six and ten days and that it is restricted by the availability of each heat removal system, its capacity, and the actual heat load. Explain the administrative controls that are used to ensure the design-basis heat load and bulk water temperature limit of 150 *F are not exceeded. l l

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