ML18139A412
| ML18139A412 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 07/03/1980 |
| From: | Sylvia B VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | Harold Denton, Varga S Office of Nuclear Reactor Regulation |
| References | |
| 570, NUDOCS 8007080419 | |
| Download: ML18139A412 (3) | |
Text
e VIRGINIA ELECTRIC AND POWER COMPANY
.RICHMOND,V:t:RGINIA 23261 July 3, 1980 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation Attn:
Mr. Steven A. Varga, Chief Operating Reactors Branch Division of Licensing U.S. Nuclear Regulatory Commission Washington, D.C.
20555
Dear Mr. Denton:
Serial No. 570 NO/HSM/jmj Docket Nos. 50-280 50-281 License Nos. DPR-32 DPR-37 ADDITIONAL INFORMATION SURRY POWER STATION UNIT NOS. 1 Al'ID 2 PROPOSED TECHNICAL SPECIFICATION CHANGE NO. 85 In response to questions posed by your staff in a recent telephone conversation, we are herein supplementing our May 15, 1980 submittal.
The responses to the questions posed are attached. If there are any further questi9ns on this matter we would be pleased to meet with your staff at their convenience.
Attachment cc:
Mr. James P. O'Reilly, Director Office of Inspection and Enforcement Region II Very truly yours,
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B. R. sy* via Manager - Nuclear Operations and Maintenance
Question 1:
Response
Question 2:
Response
Question 3:
e 1(
New Fuel Storage Area Analysis - Section 7.3.2 How was the value of 10 percent increase in pellet 0.D. arrived at? Was it based on some model for damage incurred for a dropped assembly or was it an attempt to bound the change in the resonance integral, for example?
If an assembly is dropped into an occupied storage cell, it could conceivably compact the stored assembly.
This compaction could increase the fuel moderator ratio, The value of 10 percent increase in pellet O.D. was chosen to approximate
-crushed-fuel within a cell and represents a conservative amount of change of the pellet 0.D.
New Fuel Storage Area Analysis - Section 9 What reflector conditions were assumed at the north and south extremities of the array when making the detail calculations for the low density moderation? If no reflector was assumed, justify the assumption or provide an estimate of the effect of including the effect of the walls.
A concrete reflector was modeled at the north and south extrem-ities to represent the actual storage area.
Spent Fuel Storage Area - Section 7.1.6 The submittal of May 20, 1977 (submittal for high density spent fuel racks), upon which prior approval of the spent fuel racks was based gave 0.919 as the keff for the "worst case normal configuration", assuming 3.5 w/o U-235 enrichment and a can thickness of 0.085 inches.
Using sensitivity values from the present submittal, this converts to a present value of 0.950 for 4.1 w/o U-235 and 0.90 inch wall thickness (6K = -0.003 for increased wall thickness and +0.034 for increased enrichment).
This is to be compared to a value of 0.921 for the present calculation.
Please explain this apparent discrepancy.
--~~r~"-*-
Responses:
The original submittal of May 20, 1977 was based upon the excessively conservative values calculated by DOT III.
The present calculations are based on values calculpted by KENO IV from which much of the excess conservation of DOT III has been removed.
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