ML20092G197
| ML20092G197 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 02/13/1992 |
| From: | Broughton T GENERAL PUBLIC UTILITIES CORP. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| C311-92-2018, NUDOCS 9202200027 | |
| Download: ML20092G197 (3) | |
Text
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a GPU Nu-tear Corporation gggf Post Office Box 480 I.
Route 441 South Middletown, Pennsylvania 17057 0191 717 944 7621 TELEX 84 2386 Writer's Direct Dial Number:
February 13, 1992 C311-92-2018 U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C.
20555
Dear Sir:
Subject:
Three Mile Island Nuclear' Station, Unit 1 (TMI-1)
Operating License No. DPR-50 Docket No. 50-289 Response to Request for Additional Information Regarding Spent Fuel Pool Rerack Enclosed is the GPU Nuclear response to a request for additional information contained in the NRC's letter dated January 15, 1992 regarding rerack of the spent fuel pool.
If any additional information is required please advise.
Sincerely, l
T g
Vice President and Director, THI-1 TGB/DJD/amk
Enclosure:
THI-l Response to NRC Request for Additional Information Regarding Spent Fuel Pool Reracking cc: THI-l Senior Resident Inspector Region I Administrator l
THI-1 NRC Project Manager-9202200027 920213'
'l PDR ADOCK 0D000289
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g 3119201<R GPU Nuclear Corporation is a subsidiary of General Public Utdities Corporation
C'311-92-2018 Page 1 of 2 ENCLOSVRE THI-l Response to NRC Request for Additional Information Reaittdino Soent Fuel Pool Rerack Ouestion 1.m The proposal to rerack the spent fuel pool appears to violate the design bases u)on which the spent fuel cooling system has been established.
The proposal slows maximum bulk pool temperatures of 158.35'F for an offload of 90 assemblies with 1 train operating, and maximum bulk pool temperatures of 156.05 and 154.56*F for full core offloads while the corresponding temperatures shown in the design basis are 135'F and 147'F, respectively.
Justify this change in your design basis or describe any modifications planned for the spent fuel pool heat generation load and/or cooling process as to comply with your design basis.
RESPONSE
The curre..c design basis of the THI-1 Spent Fuel Pool Cooling (SFPC) System remains unchanged by the proposed reracking of the pool.
As stated in the THI-l FSAR Section 9.4.1, the design basis stipulates that with 521 fuel assemblies in the Spent Fuel Pool (occupying 521 of the 752 storage locations provided by the original storage racks) and with only one Spent Fuel Pool Cooler in operation, the temperature of the pool will be 135'F. Additionally, for an inventory of 574 spent fuel assemblies and a full core off-load of 177 assemblies (751 total assemblies - full original storage racks), the pool temperature will be 147"F when both Spent Fuel Pool Coolers are in operation.
The cooling capacity required to achieve these conditions constitutes.the design basis of the THI-l Spent Fuel Pool Cooling System.
This cooling capacity remains undiminished as a result of the proposed reracking of the Spcnt Fuel Pool. However, the proposed reracking increans the maximum number of storage locations in Pool "A" from 256 to -1,494, thus raising the total number of storage spaces from 752 to 1,990.
The pool water temperatures i
reported in the licensing submittal are based on far larger inventories than those capable of being achieved using the original storage racks.
The-scenario resulting in a maximum bulk pool temperature of 158.35'F, for example, assumes-1,840 assemblles in the Spent Fuel Pool with only one Spent Fuel Pool Cooler in operation. With both coolers in operation and a full core off-load of 177 assemblies (instead of a normal discharge of 80 assemblies) for a total inventory of 1,937 assemblies, the maximum bulk pool temperature will be 156.05"F. Both of these temperatures are well below the boiling point and the design temperature of the Spent Fuel Pool Cooling System (250 F) and confirm that the SFCS remains capable of providing sufficient cooling for the increased heat load.
As noted in Holtec Report HI-89407, Table 5.5.2 (previously submitted) the revised minimum time-to-boil for the worst case is 10.26 hours3.009259e-4 days <br />0.00722 hours <br />4.298942e-5 weeks <br />9.893e-6 months <br />. This result does not effect the existing FSAR 9.4.1 design basis conclusion that in the event of simultaneous loss of both spent fuel cooling loops adequate time is available to restore one of the spent fuel cooling loop.
311920lLL1R
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. _ - C311-92-2018 Page 2 of 2 Also as noted is HI 89407, Section 5.5, the revised TM1-1 maximum pool bulk tem)eratures are_less than those recently licerised.at Indian Point - 2 and-.
Diaalo Canyon 1 and c.
3 The increase in the inventory of stored fuel assemblies-due to the proposed -
rerack does not have a significant impact on the existing Spent Fuel Cooling trains in operation) the maximum pool water temperature is below 150(with 2 System design basis since:- (1) for the normal discharge scenario F,(2) for the postulated full core offload case (with one cooling train - in operation) the maximum water temperature is well below 212*F, and (3) adequate i
time is available to restore one loop of spent fuel cooling before boiling occurs in the event of loss of both_ SFCS loops under the worst case discharge scenario.
These bulk pool -temperatures are described in HI-89407 Tables 5.5.1 and 5.5.2.
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