ML19262B978

Responds to NRC 791119 Position Re Containment Purge & Vent Valve Operation.Purging & Venting Performed When Needed to Improve Working Conditions

ML19262B978
Person / Time
Site:	Trojan File:Portland General Electric icon.png
Issue date:	01/14/1980
From:	Lindblad W PORTLAND GENERAL ELECTRIC CO.
To:	Schwencer A Office of Nuclear Reactor Regulation
References
TAC-08291, TAC-8291, NUDOCS 8001220368
Download: ML19262B978 (2)

Text

~

~' M _

I2JL..i r c.'_! : : :37..: ^

January 14, 1980 Trojan Nuclear Plant Docket 50-344 License NPF-1 Director of Nuclear Reactor Regulation ATTN:

Mr. A. Schwencer, Chief Operating Reactors Branch !/1 Division of Operating Reactors U. S. Nuclear Regulatory Commission Washington, D. C.

20555

Dear Sir:

Your letter of November 19, 1979 provided the interim NRC position for Containment purge and vent valve operation pending resolution of isola-tion valve operability. We have completed a review of your letter and provide the following in response.

1.

Whenever Containment integrity is required, emphasis has been placed on operating the Containment in a passive mode as much as possible.

Purging and venting times are main-tained as low as achievable.

Purging and venting is per-formed only when there is an established need to improve working conditions to perform a safety-related surveil-lance or maintenance activity and to maintain Containment pressure within Technical Specification limits.

2.

The 54-in. Containment purge and vent isolation valves are maintained closed during Plant operation (Modes 1, 2, 3 and

4) as described in my letter to you dated November 19, 1979.

>A modification to the purge system (ie, installation of a mini purge system) is under development. Valves used in the mini purge system will be qualified in accordance with the guidelines provided in your September 27, 1979 letter.

Qualification of the existing 54-in. valves with regard to operability during and following a LOCA is not planned at this time; these valves will remain in the closed position during operation.

a.

With regard to the 8-in. Hydrogen Vent System 9

motor-operated isolation valves, the valve manu-1 facturer (BIF) has informed us that the valves S

do 90 012 0 0 M l~785 187

~

h :~ l i~ d 3 5. K '^! E '."."~ C 1.T ',2..l Mr. A. Schwencer January 14, 1979 Page 2 can be safely closed under the most severe design basis accident flow condition loading without dam-aging critical valve parts from an open position of 50 degrees. Therefore, as an interim measure, PGE will limit the opening of the Hydrogen Vent System isolation valves to 50 degrees.

This will be fully implenented by February 1,1980.

On a long-term approach, we are pursuing complete quali-fication of the 8-in. Hydrogen Vent System isola-tion valves with BIF.

b.

In the Trojan plant design, a Containment Isolation Signal (CIS) will close the Hydrogen Vent System isolation valves. A review of all ESFAS circuits incorporating the manual override feature was con-ducted previously and the result was submitted to the NRC in a letter dated January 3, 1978.

It was concluded that there are no instances when overrid-ing of one ESFAS circuit will cause the bypass of any other ESFAS signal.

In addition, the high Con-tainment pressure signal will also close the valves and cannot be overriden.

Please note that Trojan Technical Specifcation 4.6.4.3 (Appendix A to FOL NPF-1) requires opening the 8-in. Hydrogen Vent System isolation valves for 15 min once every 31 days and verifying 140 cfm +10 percent every 18 months. Calculations have been performed to show that opening of these 8-in. valves no more than 50 degrees will have a negligible effect on the flow rate (140 cfm). However, the 18 month surveillance test will be performed during the forthcoming refueling outage to verify this flow rate.

Sincerely, E&W m.

k_ fLincolad

.a.

Vice President Enginee ring-Cons t ruc tion c:

Mr. Lynn Frank, Director State of Oregon Department of Energy 1785 188