ML20086R178
| ML20086R178 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 10/26/1972 |
| From: | Ragone S VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | Deyoung R US ATOMIC ENERGY COMMISSION (AEC) |
| Shared Package | |
| ML20086R145 | List: |
| References | |
| NUDOCS 8402280717 | |
| Download: ML20086R178 (2) | |
Text
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> og u vinGmia ct.ccinic ano eo.cn counanv. seicauono. VIRGlHI A 23269 M rs R. C. DeYoung, Assistant Di rector er 2 6, 32 for Pressurized Water Reactors Di rectorate of t.icensing United States Atomic Energy Comnission Docket Nos. 50-280 Vashington, D. C.
20545 50-281
Dear Mr. DeYoung:
We have reviewed your letter dated September 26, 1972, and your request that we review the proposed design of Surry Power Station Units I and 2 to determine if failure of non-Category I (seismic) equipment might potentially adversely affect safety related equipment required for a safe j
shutdown of the facilities.
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We have also reviewed the abnormal occurrence report concerning the referenced Quad Cities Unit 1 incident as reported in Volume 18, No. 27.
j page 6ff, of the Atomic Energy Clearinghouse (Weekly issue) dated July 3, I
1972.
From the description contained in this report, it appears that the
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Quad Cities Unit I circulating water system is equipped with a circulating water flow reversal system used for condenser tube cleaning.
The circulating water system for Surry Power Station Units 1 and 2 differs significantly 4
from the Quad Cities Unit I system in that the tube c1 caning system consists of a sponge rubber ball injection and catch system.
Therefore, the circulating water system for Surry Units I and 2 is a straight through cooling system and does not require the operation of large valves to reverse flow for i
l tube cleaning during operation.
In addition, other design considerations will preclude an occurrence of this type from happening at Surry Units I and 2:
1, The circulating water butterfly valves are motor operated valves and not as subject to rapid closure as hydraulic operated valves. Therefore, the oI..
probability of damaging the rubber expansion b'D, f
Joints from sudden closure of a valve is signifi-q\\
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cantly reduced.
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The rubber expansion Joints are designed to
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I withstand the maximum head of the high level p
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Intake canal.
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3 The circulating water valves are designed to withstand the maximum head of the high level intake canal.
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The circulating water valves will not be closed during operation except to isolate one half of one shell for maintenance purposes.
Therefore, the probability of an occurrence such as quad Cities happening at Surry Units 1 and 2 is practically non-existent.
However, in response to your request, we have reviewed the proposed design of Surry Units 1 and 2 to determine the potentially adverse ef fects of the failure of any non-Category I (seismic) component.
In the unilkely event of a catastrophic failure of the non-Category 1 (seismic) circulating water system or the fire protection system, and a subsequent uncontrolled discharge from such a ~ failure, there would be a potential of adversely affecting the performance of some safety related equipment required for safe shutdown of the facilities or required to limit consequences of an accident.
A detailed in-depth review of all safety related equipment locations wi th _ respgnt uttheJo_tential break locations will be continted and provis_ ions will be made to ensure thatithe equipment Ls_gratected from potential floodine.
Although final decisions have not been made, considera-tion has been given to the use of weirs, watertight barriers and/or doors, level indication interl'ocked with circulating water valves, system component
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elevation and system design to ensure that the safety related equipnent is t.
p rotected.
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As the review progresses and the protective measures are I
developed, they will be discussed with the AEC in detail, it is expected l
that the detailed designs will be completed within six weeks and the necessary protection equipnent and devices will be installed as soon as -
the designs are finalized.
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Very truly yours,,
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V i
Stanley Ragone g
Vice President l
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