ML17192A574
| ML17192A574 | |
| Person / Time | |
|---|---|
| Site: | Dresden, Quad Cities, Zion  |
| Issue date: | 03/14/1980 |
| From: | Naughton W COMMONWEALTH EDISON CO. |
| To: | Eisenhut D Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8003180345 | |
| Download: ML17192A574 (3) | |
Text
e Commonwel Edison One First National Plaza, Chicago, Illinois Address Reply to: Post Office Box 767 Chicago, Illinois 60690 March 14, 1980 Mr. D. G. Eisenhut, Acting Director Division of Operating Reactors Office of *Nuclear Reactor Regulation
- u. S. Nuclear Regulatory Commission Washington, DC 20555
Subject:
Dresden Station Units 1, 2 and 3 Quad Cities Station Units 1 and 2 Zion Station Units 1 and 2 Response to Request for Information Concerning LWR Primary.Coolant System (PCS)
Pressure Isolation Valves NRC Docket Nos. 50-10/237/249, 50-254/265, ~nd 50-295/304 Reference (a):
February 23, 1980 letter from D. G.
Eisenhut to All LWR Licensees
Dear Mr. Eisenhut:
Reference (a) requested information relevant to existing Primary Coolant System (PCS) pressure isolation configurations at Commonwealth Edison Company's Dresden, Quad Cities and Zion Nuclear Power Stations.
Pursuant to that request, following are the results of Commonwealth Edison's reviews.
A~
Dresden and Quad Cities Stations At Dresden Station Units 1, 2 and 3 and at Quad Cities Station Units 1 and 2, a review of piping systems which connect to the PCS has determined that the high pressur~ portions include, in additon to any check valves, two or more motor bperated valves in series.
Thus, the configurations delineated in Reference (a) do not exist for these units and no additional action is deemed necessary at this ti~e.
B.
Zion Station At Zion Station Units 1 and 2, there are two Low Pressure Inject ion Sys terns (LP IS) - the Safety Inject ion 1'oo/
(SI) System and the Residual Heat Removal (RHR)
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Commonwealth Edison Mr. D. G. Eisenhut, Acting Director*
March 14, 1980 Page 2 Both systems have a hot leg and cold leg injection flow path.
The hot leg piping in the SI system contains two check valves in series with a normally closed MOV in the high pressure section of the piping.
Because of the normally closed MOV, this arrangement is not considered an Event V valve configuration.
The hot leg injection piping in the RHR system contains two check valves in series with a normally open MOV in the high pressure section of the piping.
This is an Event V valve configuration.
The cold leg injection piping differs between the two LPIS.. The RHR system has three check valves in series with a normally open MOV in the high pressure section of piping.
Because of the third check valve in the line, this arrangement is not *considered an Event V valve configuration.
The SI system cold leg injection piping has two check valves in series with a normally open MOV in the high pressure section of piping.
This is an Event V valve configuration.
Once each refueling outage, a leak test is performed on the first check valv~ of each cold leg injection line (PT-2M) to verify their integrity.
The results of this test indicate that the check valves do not leak.or lack integrity.
Currently, no tests are performed to verify the integrity of the second check valve of each SI cold leg injection line or either check valve in the RHR hot leg injection line.
In addition, plant procedures at Zion Station have been revised as follows:
l~
Both check valves of each SI cold leg injection line will be tested every time the primary coolant system (PCS) pressure is brought to within 100 psig of the maximum possible pressure on the low pressure side of these check valves.
- 2.
Both check valves of each RHR hot leg
. injection line will be tested every time.the PCS pressure i~ brought to within 100 psig of the maximum possible pressure on the low pressure side of these check valves.
Commonwealth Edison Mr. D. G. Eisenhut, Acting Director March. 14, 1980 Page 3 Commonwealth Edison has noted the utilization of the Reactor Safety Study (RSS),
WASH~l400, as the primary basis for the safety review delineated in Reference (a).
Commonwealth Edisbn firmly believes that probabilistic risk assessments, such as the RSS, can be very useful in identifying and resolving safety concerns especially when utilized on plant specific designs.
Commonwealth Edison urges the NRC Staff to continue to use this approach in future reviews.
Please address any additional questions that you might have concerning this matter to this office.
One (1) signed original and seventy-nine (79) copies of this letter are provided for your use.
SUBSCRIBED and SWORN. to be fore..1)1 ~ t ~ i s
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2338A Verf.truly yours,
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William F. Nau~h;~-- ---
Nuclear Licensing Administrator Pressurized Water Reactors
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