W3P83-4150, Informs of Redesign of Component Cooling Water Sys to Cure Concerns of Generic Ltr 83-10A Re TMI Action Item II.K.3.5, Automatic Trip of Reactor Coolant Pumps & of Inadvertent Safety Injection Actuation Signal
| ML20083G338 | |
| Person / Time | |
|---|---|
| Site: | Waterford  |
| Issue date: | 12/29/1983 |
| From: | Cook K LOUISIANA POWER & LIGHT CO. |
| To: | Knighton G Office of Nuclear Reactor Regulation |
| References | |
| TASK-2.K.3.05, TASK-TM GL-83-10A, W3P83-4150, NUDOCS 8401040210 | |
| Download: ML20083G338 (4) | |
Text
{{#Wiki_filter:- LOUISIANA 242 OuAnONOc srmr POWER & LIGHT P O BOX 6008. NEW ORLEANS. LOUISL'.NA 70174. (504) 366 2345 NuSNsysY$ December 29, 1983 W3P83-4150 3-A1.01.04 Q-3-B41 Director of Nuclear Reactor Regulation Attention: Mr. G.W. Knighton, Chief Licensing Branch No. 3 Division of Licensing U.S. Nuclear Regulatory Commission Washington, D.C. 20555
SUBJECT:
Waterford SES Unit 3 Docket No. 50-382 Component Cooling Water to Reactor Coolant Pumps
REFERENCE:
W3P83-2115 dated June 27, 1983
Dear Sir:
The Component Cooling Water System (CCWS) at Waterford 3 provides cooling to essential plant auxiliary components during all modes of operation including postulated accidents to the extent the auxiliary components are required for safe shutdown and accident mitigation. Cooling is alao supplied by the CCWS to non-essential components such as the Reactor Coolant Pumps (RCPs) and motors, during normal shutdown, normal operation and refueling. The current CCWS design requires, upon receipt of a safety injection actuation signal (SIAS), that the radundant CCWS cooling loops be isolated from each other and that the non-essential loops (including RCPs) be isolated from the essential portions by closing the normally open safety-related isolation valves in series. This design, included in the conceptual flow diagram of Attachment #1, was reviewed and accepted in the original issuance of the Waterford SER. We are presently redesigning the CCWS to allow for utilization of the Containment Spray Actuation Signal (CSAS) to isolate cooling water flow to the RCPs in lieu of the SIAS and Containment Isolation Actuation Signal (CIAS). The CSAS is activated by a high-high containment pressure signal with a coincident SIAS. Both the SIAS and CIAS are activated on either high containment pressure or low pressurizer pressure. Transferring the closure signal of the CCW containment isolation and header isolation valves from SIAS/CIAS to CSAS would reduce the frequency of unnecessary termination of cooling water supply to the RCP seals. 8401040210 831229 <D PDR ADOCK 05G00382 Ugp[ A PDR t j
,Page 2 W3P83-4150 3-A1.01.04 Q-3-B41 Our redesign stems from two main concerns: 1. In answer to Generic Letter 83-10a - Resolution of TMI Action Item II.K.3.5, Automatic Trip of Reactor Coolant Pumps, LP&L intends to implement the CE Owners " trip two/run two" RCP strategy as described in the referenced letter. This will require maintaining cooling water flow to the RCPs following SIAS at least until the transient has been diagnosed. 2. Inadvertent SIAS or CIAS will introduce operational limitations on the RCPs due to CCW isolation. The termination of CCW flow could increase the average length of an outnge, due to seal inspection delays, if flow is not reestablished within a short period of time. Our redesign will be similar to that utilized on Westinghouse plants. While the redundant CCW trains will still be isolated from each other on SIAS, the designated CCW train will continue to feed cooling water to the RCPs. The tentative valve changes necessary to implement this conceptual redesign are included in Attachment #2. We are providing this initial information in order to assist you in scheduling and initiating your review. The final design documents will be available for review in mid-January, 1984. We will contact our Project Manager at that time and schedule a meeting with your reviewer. Considering the Spring, 1984 fuel load date for Waterford, we request a timely concurrence review meeting in support of our schedule no later than the end of January. Should you have any questions or comments on this matter, please feel free to contact me or Mike Meisner at (504) 363-8938. Yours very truly, ?l K. W. Cook Nuclear Support & Licensing Manager KWC/MJM/cb Attachments cc: W.M. Stevenson, E.L. Blake, J. Wilson (NRC), R. Stevens (NRC), G.L. Constalbe (NRC, Resident Inspector)
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ATTACHMEhT 2 l VALVE (S) SERVICE MODIFICATIONS 3CC-F120A Header Isolation Change signal from SIAS to CSAS. 3CC-F122A 3CC-TM169 CCW Temp. Control (1) Change valve from F.O. to F.C. A/B on Letdown HX (2) Add controls to close on SIAS. 3CC-FM138 CCW Temp. Control (1) Change valve from F.O. to F.C. A/B on Fuel Pool HX 3CC-F130A Shutdown HX CCW (1) Change controls so that designated 3CC-F131B Outlet train valve goes full open on CSAS - remains as is on SIAS. Other train valve goes full open on SIAS as in present design. (2) Change valve from F.O. to F.C. including accumulator. 2CC-F146A/B CCW Supply & (1) Change controls to close on 2CC-F243A/B Return to RCP's CSAS instead of CIAS. 2CC-F147A/B & CEDM Coolers o -}}