ML20039B222

Responds to IE Bulletin 80-06 Re ESF Reset Controls. Investigation of Electrical Schematic Diagrams for Steam/ Water Dump Sys Has Been Initiated,Consisting of Amend 18 to Fsar.Also Forwards Application to Amend License DPR-34

ML20039B222
Person / Time
Site:	Fort Saint Vrain
Issue date:	10/30/1981
From:	Lee O PUBLIC SERVICE CO. OF COLORADO
To:	Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML20039B223	List: ML20039B222 ML20039B227
References
REF-SSINS-6820 IEB-80-06, IEB-80-6, P-81265, NUDOCS 8112220435
Download: ML20039B222 (3)

Text

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P.O. BOX 840 DENVER, COLOR ADO 80201

. October 30, 1981 Fort St. Vrain Unit No.1 P-81265 Mr. Karl V. Seyfrit, Director  ?@@ MOW 1FQ t

Region IV ,# f Office of Inspection and Enforcement l 10f - 91981 f Nuclear Regulatory Commission 611 Ryan Plaza Drive

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Sulte 1000 Arlington, Texas 76012 Docket No. 50-267

Subject:

IE Bulletin No. 80-06

References:

1) NRC letter fron1 K.V. Seyfrit-to C.K. Millen, G-80041, dated 3/13/80

2) PSC letter from D. Warembourg to K.V. Seyfrit, P-80063 dated 3/27/80

Dear Mr. Seyfrit:

In letter P-80063 PSC informed the NRC of PSC's determination that the required action of IE Bulletin No. 80-f'6 applied only ~ to PWRs and BWRs and not to HTGRs. In September 1981, Mr. George Kuzmycz of the NRC contacted PSC's Nuclear Engineering._ Division, '

stating that PSC's response to IE Bulletin No. 80-06 was unacceptable, and a.more detailed response is required. This letter will serve as an interim response to IE Bulletin No. 80-06, outlining PSC's plan for investigating and responding to this Bulletin.

The engineered safety features at FSV are defined in PSC's answer to NRC question 7.7 in Amendment No.18 to the FSAR (attached). The 6 engineered safety features at FSV are: 1) the reactor building ventilation exhaust fans and filters, 2) the steam / water dump system,-

3) the steam generator feedwater flow limiters , 4) the PCRV penetration flow restriction devices, 5) the PCRV penetration secondary closures, 6) the PCRV safety valves. Of these engineered safety features, only the steam / water dump tem receives an actuation signal, and therefore requires e i as specified in IE Bulletin No. 80-06.

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-g' Page 2 October 30, 1981 The reactor building ventilation exhaust fans, filters and their controls continue operating in their normal manner during a PCRV leak accident. This particular engineered safety feature has no actuation signal which changes the mode of operation .during accident conditions. 'The steam generator . . feedwater flow limiters, PCRV penetration flow restriction devices, and PCRV penetration secondary closures are mechanical design features nut associated with electronic circuitry. The PCRV rupture discs and safety valves are mechanical pressure relief devices which do not receive electronic actuation signals.

The steam generator steam / water dump system can be automatically initiated by three different actuating signals: 1) a high- primary coolant moisture signal from the primary coolant moisture monitors,

2) a high primary coolant pressure signal from the primary coolant pressure monitors, 3) a high pressure signal from the pressure sensors -in any one of the 12 steam generator module penetrations.

The consequences of a steam / water dump differ in one facet depending-on the actuation signal. A steam / water' dump initiated by a high PCRV pressure actuation signal or by a high PCRV moisture actuation signal is accompanied by an automatic reactor scram, whereas a steam / water ;4 dump initiated by high steam generator module penetration pressure is '

not' accompanied by a reactor scram. i

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The automatic consequences of a steam / water dump actuating signal are as follows for the affected loop: 1) closing the helium ci rcul ator_ steam turbine inlet and outlet valves (trip- both helium circulators),2) closing the circulator bypass block valve, 3) closing the reheat inlet attemperator line block valve, 4) closing the _ reheat inlet attemperator line flow control valve, 5) closing the -

superheat header outlet stop check valve, 6) closing the hot reheat stop check valve, 7) closing the feedwater header block valve, 8)

. closing the feedwater header flow control valve, 9) opening the two j parallel. steam / water dump valves,10) reactor scram, except when the

steam water dump actuation signal is M lh pressure in'a steam generator module penetration as mentioned aoove,-11) upon reactor l

scram the main turbine load is automatically reduced to zero in about-

! 2 minutes, and the main turbine is then automatically tripped. In the event of a loop shutdown (which occurs upon initiation of a steam /waur dump) turbine -load is automatically. reduced to 50% of the load existing at initiation of the loop shutdown. All of t7e above-l- listed equipment items are safety related except 4) the reheat inlet 4 attemperator line flow control valve and 11) the main turbine 4

automatic load reduction circuitry.

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-* P-81265 Page 3 October 30, 1981 PSC has initiated an investigation of electrical schematic diagrams associated with the steam / water dump system at the elementary diagram level as required by Licensee Action 1 of IE Bulletin No. 80-06. The purpose of this investigation is to determine from electrical schematic diagrams the results of resetting each of the three automatic steam / water dump actuation signals on the nine dif ferent safety related equipment items whose position or operational mode changes upon initiation of a' steam water dump. Upon reset of the actuation signal, all of these safety related equipment items should remain in their emergency mode.

PSC will further verify that the actual installed instrumentation and controls at the facility are consistent with the schematic diagrams reviewed as required by Licensee Action 2 of IE Bulletin No.

80-06. PSC considers that the results of previous actual steam / water dump occurrences coupled with administrative requirements which govern the operation of FSV are sufficient to meet the intent of-Licensee Action 2. PSC intends to present this evidence to the NRC in the final response to IE Bulletin No. 80-06 in lieu of conducting the functional test required in Licensee Action 2.

PSC will submit the final response to IE Bulletin No. 80-06 to the NRC by no later than January 15, 1982. The final response will contain the results of tne detailed review of applicable schematic diagrams specified in Licssee Action 1, and evidence from previous-steam / water dumps to demonstrate that the actual installed instrumentation and control s at FSV are consistent with tnese schematics. Should PSC discover safety-related equ'pment which does not remain in its emergency mode upon reset of a steam / water dump actuation signal, PSC will list _ these equipment items and describe a corrective action program to resolve the problems per IE Bulletin No.

80-06 Licensee Actions 3 and 4 in PSC's final response.

Very truly yours, h .1v

0. R. Lee, Vice President Electric Production ORL/JRJ:pa

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