ML17252A950

Letter Reporting a 10/09/1973 Occurrence Relating to M0-3-1301-1 Valve in the Isolation Condenser System Failed to Operate Correctly - Dresden Unit 3

ML17252A950
Person / Time
Site:	Dresden
Issue date:	10/18/1973
From:	Worden W P Commonwealth Edison Co
To:	Giambusso A Commonwealth Edison Co
References
WPW Ltr.#782-73
Download: ML17252A950 (2)

Text

CommonwealAdison One First National Sa. Chicago, Illinois Address Reply to: Post Office Box 767 Chicago, Illinois 60690 WPW Ltr.#782-73 Mr. A. Giambusso Deputy Director for Reactor Projects Directorate of Licensing U. S. Atomic Energy Commission Washington, D. C. 20545 50-249 Dresden Nuclear Power Station R. R. #1 Morris, Illinois October 18, 1973 SU.BJECT:. LICENSE DPR-25, DRESDEN NUCLEAR POWER STATION, UNIT #3, SECTION 6.6.B.2 OF THE TECHNICAL SPECIFICATIONS ISOLATION CONDENSER VALVE FAILURE

References:

1) Notification Qf Region III of ABC Regulatory Operations Telephone: F. Maura, 1100 hours0.0127 days <br />0.306 hours <br />0.00182 weeks <br />4.1855e-4 months <br /> on October 10, 1973 Telegram: Mr. Keppler, 1100. hours on-October 10, 1973

• 2) Drawings M-28 Dresden s*tation P & ID.

Dear Mr. Giambusso:

. This letter is .to report a condition relating to the operation of the unit at 1450 hours0.0168 days <br />0.403 hours <br />0.0024 weeks <br />5.51725e-4 months <br />; on October 9, 1973. At this time M0-3-1301-:1 valve in the isolation condensez:: system failed to operate correctly. This -malfunction is contrary to. section 3.5.E.l_of the Technical Specifications which requires that the isolation condenser be operable when reactor pressure is above 90 psig and irradiated fuel is in the vessel. PROBLEM Following performance of Isolation Condenser high steam flow, and high condensate flow surveillance, valve M03-1301-l failed to open when the isolation was reset. The supply breaker for the M03*1301-l valve was found tripped. It was reset.and the valve then tested FHe Cy. At the time of the failure, the reactor was in the "Run". mode and .. thewi power was-2244. *-The was -ope-rs-ting at-a steady . -. electric.-load of 740 megawatts. Reactor pressure was 993 psig. (\f

• • • .. Mr. A. Giambusso e October 18, 1973 'INVESTIGATION An investigation into the* problem failed to provide a cause for the breaker trip. As stated previously, the problem corrected itself once the breaker was reset. This problem has occurred on other valve breakers and is presently under investigation. For the present status of the breaker investigation, see Dresden Station's report of a of valve M03-1501-20B October 1, 1973. CORRECTIVE ACTION The immediate corrective action taken was to reset the breaker trip and attempt a second valve* operation. The second at.tempt to operate the valve proved to be successful with the valve operating as designed. Also, this type of breaker failure. has been under* investigation and at this time a cause for the breaker trips has* npt been found. The investigation of this type of failure -will continue until the problem has been solved. Any further correct.ive actions will be based on the finds of the investigation. EVALUATION During the failure of the M03-1301-l valve," the safety of the plant and public was not iri jeopardy. With the valve failing closed, it assurred primary containment integrity. However, with the valve the isolation condenser system would be inoperable. At the time of the failure, the high pressure core injection (HPCi) and Auto Blowdown systems were operational. Continued operation of the plant was considered safe because of .the short time valve 3-1301-1 was not operational the operational status of the high pressure injection and auto blowdown systems. WPW:dQ S.incerely, "3'.Rs-Jl j. W. P. Worden Superi11tendent