ML17208B070

Provides Info on Compliance W/Tmi Lessons Learned Task Force short-term Item Re Auxiliary Feedwater Sys Flow Indication, in Response to NRC 791211 Request.Util Installing Single Control Grade Flow Indication Channel Per Feedline

ML17208B070
Person / Time
Site:	Millstone, Haddam Neck  File:Connecticut Yankee Atomic Power Co icon.png
Issue date:	12/18/1979
From:	Counsil W NORTHEAST UTILITIES
To:	Harold Denton Office of Nuclear Reactor Regulation
References
RTR-NUREG-0578, RTR-NUREG-578 TAC-44705, TAC-44746, NUDOCS 7912270318
Download: ML17208B070 (4)

Text

REGULATORY ORMAT ION DIS TRIBUTION SY (RIDS3 ACCESSION NSR$ 7912270318 OOC DATE'9/12/18

~ NOTARIZED! NO DOCKET FACIE,:50~213 Haadam Nick Planti Connecticut Yankee Atomic Power Co 05000213 Millstone Nuclear Power Statfong Unit 2i Northeast Nu 05000336 AUT ~ ME AUTHOR AFFILIATION COUNSILisf,G ~ ~ Northeast Utilities REC IP,NAME RECIPI EN T AFFIl. IAT ION DENTON,H,'R, Of f ice of Nuclear Reactor Regulation

SUBJECT:

Provides info re compliance w/TMI Lessors Lea~ned Task Force short term i tern re auxi lan y feedwater sys flow indicationi 1

in response to NRC 791211 request ~ Uti l instal ling single control gr ade f ow indi cat i on channe'I pet feed l ine.

1 DISTRIBUTION CODE: 505YS COPIES RECEIYED:LTR TITLE: Reip to Lesson Learn Task Force

f. ENCL. 4) SIZE:

NOTES; I C', ~ . ~~ Q ~ ~ ~

Westinghouse

~Mt PIT &IC~~

REC IP IEN T COPIES RECIPIENT COPIES ID CODE/NAME LT TR EIVC ID CODE/NAME LfTR ENCL,',

ACT 1ON: 10 BC INTERNAL: 1 Hh.'ts F LK w2, 1 17 I L E 19 TA/EDO 1 2 iVRC PDR 1 20 CORE PERF SR 1 21 ENG UR 1 22 REALS. SFTY Sh f 23 PLANT SYS BR 1 2~ EEB 1 25 EFLT TRT SYS 1 3 LPDR 1 NSIC 1 5 J OLSHIN SKI 1 6 J KERRIGAN 1 1 7 J BURD I Qii 1 5 C AILLIS 1 9 G IMBRO 1 M FIELDS 1 N ANDERSOIV 1 OELD 1 P 0 HE ILLY 1 EXTEHNAI o 26 ACRS 16 1 Pi ~QQ <g Q~ <

C' mewSan C.~ML 52 TOTAL NUBBER OF COPIES REQUIRED: LTTR ~ ENCL o

Alp

THt ccHNtcTTOUT tcHT Amo PomtR ccMPANT THS HARTVORO tltCTRS" LIGHTCOMPANV P.o. BOX 270 HSSTTRN M SSACHOStTTS tltCTRVC CCMPANV HARTFORO, CONNECTICUT 06101 HCAVCett WATtR POASR COMPANV (203) 6664911 HCRTHTAST OTRTTRS STTNTCt COMPANY t

ssyt THP AST TayvATAR Nt RCT COA'I@ANT December 18, 1979 Docket Nos. 50-213 50-336 Office of Nuclear Reactor Regulation Attn: . Mr. H. R. Denton, Director U. S. Nuclear Regulatory Commission Washington, D. C. 20555

References:

(1) W. G. Counsil letter to H. R. Denton dated November 21, 1979.

(2) H. R. Denton letter to All Operating Nuclear Power Plants, dated October 30, 1979.

(3) D. L. Ziemann letter to W. G. Counsil dated December 12, 1979.

Gentlemen:

Haddam Neck Plant Millstone Nuclear Power Station, Unit No. 2 Auxiliar Feedwater S stem Flow Indication to Steam Generators In Reference (1), Connecticut Yankee Atomic Power Company (CYAPCO) and Northeast Nuclear Energy Company (NNECO) responded to the NRC Staff request of Reference (2) regarding TMI Short-Term Lessons-Learned Item 2.1.7.b, Auxiliary Feedwater System Flow Indication to Steam Generators. Reference (1) indicated that for both facilities, it was intended that full compliance would be achieved by January 1, 1980. In Reference (3), the Staff amended the schedule for which additional information was requested, changing the requested date from January 1, 1980, to December 14, 1979. This request was telecopied to CYAPCO on December 11, 1979, and officially received on December 17, 1979. In response to this request, and in anticipation of a similar one for Millstone Unit No. 2, the following information is provided.

CYAPCO is proceeding with the design and installation of a single control grade flow indication channel per steam generator feedline.

.Auxiliary feedwater flow indication will be provided by using a differential pressure sensing device. This sensing device is designed to produce a differential pressure within the fluid flow stream that is proportional to fluid flow. Each of the four devices will be located in the three-inch feedwater control valve bypass line, which is the normal flow path for auxiliary feedwater at the Haddam Neck Plant. The differential pressure is +0 next fed into a pressure transmitter which produces a 4-20 ma analog signal proportional to the differential pressure. The signal is next linearized 'h a

by a square-root transmitter for direct indication on the main control board. %0T q'p

'h g

p "I 0$

02T0 P~I

Conformance to the clarification items of Reference (2) is addressed below:

In order to satisfy the single failure, criterion, the Haddam Neck Plant will rely on the existing Steam Generator Level Indication System as a backup. This alternative is in accordance with Clarification C.l of Reference (2).

(2) Surveillance procedures for calibration and testing of the instrument loops are being prepared. All equipment is readily accessible to facilitate calibration and testing as required.

(3) D.C. power to the four instrument loops is provided from an AC/DC power supply which, in turn, is supplied from the semi-vital distribu-tion panel in the Control Room. This distribution panel has the capability of being fed from either of the two emergency power sources. The enclosed drawing, No. 16103-32150, Sheet. 11A, depicts the above scheme.

(4) As stated previously, this syst: em is designed as a control grade system and meets the single failure criterion by taking credit for the existing Steam Generator Level Indication System as a backup.

The control grade components will be either upgraded, with proper Q/A documentation, or replaced to meet the long-term "safety-grade" requirements. Although not presently properly qualified from an operational standpoint, the pressure boundary components are seis-mically qualified such that auxiliary feedwater system integrity or containment boundary integrity is not compromised.

(5) The auxiliary feedwater flow channels provide an indication of feed flow with an accuracy on the order of + 10%.

For Hillstone Unit No. 2,,the existing auxiliary feedwater flow indication system is adequate to fulfillthe short-term requirements. Conformance to the clarification items of Reference (2) is addressed below:

In order to satisfy the single failure criterion, Millstone Unit No. 2 will rely on the existing Steam Generator Level Indication System as a backup. This alternative is in accordance with Clarification C.l of Reference (2).

(2) Testability of the auxiliary feedwater flow indication channels has been demonstrated since initial plant operation.

(3) Auxiliary feedwater flow instrument channels are powered from the vital instrument buses.

(4) The existing system will be upgraded in the long term to satisfy safety-grade requirements.

(5) The auxiliary feedwater flow channels provide an indication of feed flow with an accuracy within + 10%.

This system was described in the Millstone Unit No. 2 FSAR.

We trust you find the above information responsive to the requests of Reference (3).

Very truly yours, CONNECTICUT YANKEE ATOMIC POWER COMPANY NORTHEAST NUCLEAR ENERGY COMP W. G. Counsil Vice President Attachment