ML20199G484

Suppls Response to IE Bulletin 86-001,describing long-term Resolution of Single Failure Concern Re Min Flow Bypass Valve Logic for Rhr/Lpci Pumps.Hardware Mod to Valve Control Logic Will Be Performed by 861101

ML20199G484
Person / Time
Site:	Dresden, Quad Cities, 05000000
Issue date:	06/23/1986
From:	Wojnarowski J COMMONWEALTH EDISON CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
1797K, IEB-86-001, IEB-86-1, NUDOCS 8606250253
Download: ML20199G484 (2)

Text

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, x Commonwealth E:" son 2:

) One First National Plaza. Chicago. Ilhnois s

O Address Riply to. Post Office Box 767 Chicago. lilinois 60690 T

June 23, 1986 Mr. James G. Keppler

Regional Administrator U.S. Nuclear Regulatory Commission Region III 799 Roosevelt Road j Glen Ellyn, IL 60137

Subject:

Dresden Station Units 2 and 3 I

Quad Cities Station Units 1 and 2 Supplemental Response to I.E.Bulletin 86-01 NRC Docket Nos. 50-237/249 and 50-254/265 References (a): I.E. Bulletin 86 J.M. Taylor Letter to 1

G.E. BWR Facilities with OL and CP dated May 23, 1986 j (b): Letter, J.R. Wojnarowski to J.G. Keppler (NRC),

! same subject, dated May 30, 1986.

Dear Mr. Keppler:

, Commonwealth Edison has reviewed the minimum flow bypass valve logic for the RHR/LpCI pumps at Dresden and Quad Cities, and have concluded i that the single failure concern identified in the reference (a) I.E. Bulletin i

exists. We have previously provided (Reference (b)) our response to Action Items 1, 2 and 3 of IEB 86-01. This letter provides a supplemental response describing our long term resolution as required by Action Item 4 of the j Bulletin.

i Our long term resolution involves performing a hardware modification to the LpCI/RHR pump minimum flow valve control logic. The conceptual design for this modification includes removing interlocks between divisions.

Currently the 'A' and 'B' minimum flow valves are both controlled by either flow sensor in the 'A' or 'B' loop (through auxiliary relay contacts). 3 failure of either of these sensors could closis both minimum flow valves.

The modification will result in the 'A' loop flow sensor controlling only the 'A' valve, and similarly, the 'B' loop sensor controlling the 'B' valve. When the modification is implemented, the single failure r:oncern j addressed in IEB 86-01 will be eliminated.

Modification design, review, and approval should be complete for all four units by November 1, 1986. Due to the sensitivity of the work to be performed in the ECCS control cabinets, installation of the modification will be performed during the first scheduled refuel outage after completion of the design, drawing changes and any required equipment procurement. We believe the short term action of increasing operator awareness t'arough procedure changes and training is adequate justification for this time schedule.

8606250253 860623 f/I PDR ADOCK 05000237 G PDR -

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Mr. J. G. Keppler June 23, 1986 This response fulfills Action Item 4 of IRB 86-01. No further action or response is required.

Please address any questions that you or your staff may have concerning our response to this office.

One signed original is being sent directly to the USNRC Document Control Desk in Washington, D.C. for reproduction and distribution as requested in the Bulletin.

Very truly yours, J.R. Wojnarowski Nuclear Licensing Administrator la cc: US NRC Document Control Desk Washington, D.C. 20555 Region III Inspectors - D,QC SUBSORIBED AND o o befhre me this 3

day f M L/1 1, 19J8

~ ir'LA C). YYIAk Notary publ'ic j 1797K