NRC-90-0164, Changes Schedule for Commitment to Replace Two Scram Discharge Vol Vent Line Isolation Valves.Replacement Will Occur During Third Refueling Outage Due to Seismic & Time Considerations

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Changes Schedule for Commitment to Replace Two Scram Discharge Vol Vent Line Isolation Valves.Replacement Will Occur During Third Refueling Outage Due to Seismic & Time Considerations
ML20062G825
Person / Time
Site: Fermi DTE Energy icon.png
Issue date: 11/26/1990
From: Orser W
DETROIT EDISON CO.
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
CON-NRC-90-0164, CON-NRC-90-164 NUDOCS 9012030031
Download: ML20062G825 (2)


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NRC-90-0164 U. S. Nuclear Regulatory Commission Attention: Document Oontrol Desk Washington, D.C 20555

References:

1) Fermi 2 NRC Docket No. 50-341 NRC License No. NPF-43
2) Detroit Edison Letter NRC-90-0022, " Report of Reactor Containment Building Integrated Leak Rate Test Results", dated February 21, 1990

Subject:

Change in Schedule for a Commitment to Replace Two Scram Discharge Volume Vent Line Isolation Valves The purpose of this letter is to inform the NRC Staff of a revision to Detroit Edison's schedule for implementation of the subject commitment from the Reference 2 Letter.

Detroit Edison letter NRC-90-0022 reported that four Scram Discharge Volume (SDV) vent and drain valves would be replaced during the second refueling outage. These valves are C1100-F010 (inboard) and C1100-F180 (outboard) SDV vent valves, and C1100-F011 (inboard) and C1100-F181 (outboard) SDi drain valves, manufactured by Hammel-Dahl.

Past experience has been that several attempts were required for these valves to pass their Type "C" air test.

The reference letter stated that Fermi 2 was in the process raf preparing an Engineering Design Package (EDP 7571). The EDP's scope is to replace _the existing vent and drain valves with valves of more suitable leak tight design, as needed for the specific application of the Scram Discharge Volume system. The EDP also adds test tapa, and vent and drain line test block valves to facilitate individual valve leak tote testing. The drain valves will be replaced during the' second refueling outage. Also, the block valves and test taps for both the vent line and the drain line will be added to the system during the second refueling outage. Detroit Edison is revising the schedule for the replacement of the existing vent valves with new vent valves to the third refueling outage.

This change in schedule results from seismic considerations associated with the size of the valves and actuators and the lack of time necessary to complete the design and procurement of these components for the second refueling outage. During preparation of the EDP, l

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U. S. Nuclear R:gulaitory Commission NRC-90-0%4 November 26, 1990 Page 2 engineering personnel determined that the weight of available, quallfled valvt assemblies posed a supportability problem. Extensive piping rework and/or structural analysis of the existing support system would be required to locate the larger valves where they could be seismically qualified or an actuator of considerably less weight needs to be qualified. This matter is being pursued, however, there is not sufficient lead time for resolution prior to the second refueling outage.

The block valves and test taps on the vent line will be installed to facilitate local leakage rate testing of the existing vent line valves. This modification will enable plant personnel to flush the vent line as needed to remove particulate which is suspected to be a potential contributor to the degradation of the valves' icak tightness.

The replacement of the SDV vent line isolation valves C11-F010 and C11-F180 will necessarily be deferred until the third refueling outage.

If you have any questions please contact. Mr. Joseph Pendergast, Compliance Engineer at (313) 586-1682.

Sincerely, M/

cet A. B. Davis R. W. DeFayette W. G. Rogers J. F. St,ang USNRC RIII l

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