ML20085L650

AO 50-267/75/24A:on 741222,static Seal on C-2101 (Helium Circulator C) Released During Removal of Temporary Jumpers. Caused by Blown Fuse & Seal Release Valve Leak.All Circulator Brake & Seal Vent Valves Checked

ML20085L650
Person / Time
Site:	Fort Saint Vrain
Issue date:	01/25/1975
From:	Brey H, Swart F PUBLIC SERVICE CO. OF COLORADO
To:
References
AO-50-267-75-24, NUDOCS 8311020206
Download: ML20085L650 (4)

Text

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o- ;o RF1' ORT DATE: Janunrv 25. 1975 ABNORMAL' OCCURRENCE OCCURRENCE DATE: December 22, 1974 FORT ST. VRAIN NUCLEAR GENERATING STATION PUBLIC SERVICE COMPANY OF COLORADO P. O. BOX 361 PLATTEVILLE, COLORADO 80651 REPORT No, 50-267/74/24A

. FINAL IDENTIFICATION OF.

_0CCURRENCE:

The static seal on C-2101 ("A" helium circulator) was possibly accidentally released during removal of temporary jumpers following a test of the feedwater system. This is identified as an Abnormal Occurrence per definition 2.1.c of _,

the Technical Specifications.

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CONDITIONS PRIOR TO OCCURRENCE: Steady State Power Routide Shutdown IIot Shutdown Routine Load Change X Cold Shutdown .

X other (specify) _

Refueling Shutdown Plant-essentially shut down follow-1 Routine Startup ing initial-nerformance of RT-241

'(Feeduater system testing) .

The major plant- parameters at the time of the event were as :follows:

Power. 'PTR 0' 'MWth ELECT.- 0 MW7 -

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cSecondary Coolant. ' Pressure (0 psig m Temperature- -N/A' *F Flow N/A' J#/hr.-

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Primary Coolant: -Pressure 25' ~ psig-Temperaturc '101' 'F Core Inic.t-1101' *F Cotc' Outlet!

n- ' 1 Flow - . 0 .#/hr.

0 -

NN

--h._

+  ; 1 .,, ,

w a ?. : _. ..._: .L-. - = - - . - _ - - _ . - - . ~. .-

.- n U -

g G

Page 2 DESCRIPTIO:1 OF OCCURRE!:CE: -

The stat.ic seal en C-2101 helfun circulator was possibly released while replacing plant protective synten nodules and junpers previously required to run RT-241 (initial fil]iun of the etcan generatorn and f eedwater control synten test).

Thet c are tuo scal relcanc valves in series. A fuse blown while renoving ihe junpern caused one of those valven to open. Buffer-nidhuffer in.strumentation indicated flou up t.he circulator shaf t implying that the remaining ceal release valve ic leaking.

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The normal buf fer hellun syst em van placed on the circulator to prevent any priuary coolant 3cahage.

Analycis of the primary coolant taken on December 20, 1974 indicated no detectable ,

gatan activity, therefore an accidental release of primary coolant would not have represented a h uard to plant personnel or the public. A continuous air ronitor located at the PCPS support ring indicated background radiation IcVels. An analynis of prinary coolant on December 23, 1974 indicated no increast in contaminants. g APPARENT CAUSE .

Design OT OCCURRE:!CE: 1 Unusual Service Cond.

Including Environnent llanufacturc X Component Failure Installation /Const. Other (specif.y)

X Operator Procedure 1:hile removing a juuper acror.n the "A" logie circulator brake and seal interlock contacts of C-2101, the jutper apparently contantcd station ground resulting in a bloun fuse. Thin de-cuergi::cd a relay uhoac contacts hold the appropriate brr.ke and scal valvcu cloccd or open as required.

Becauce of redundant valvint; in the system, valve 11V-21191-3 had to be leaking for the seal release to occur.

ANALYSIS OF 0CCuni;E'!CE:

Bloving a fuse in the brake and seal circ..it should not in itself release the circulator neal. There are tuo serien brakn and scal relcane valves and the blo.ra fuse vauld only af f ect one of t.he scal and one of the brake releane valven.

The neal and brake hellun pressure supply valsen are in para 11c1 and are also separately fused, but the blown fuse would effect onc brahe and one seal supply valve,

Q

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LJ ~J Page 3 l CORRECTIVE.

ACTIO:i:

A check was raade of all circulator brake and seal vent valves. This was done by checking each valve in service. The results of that test indicated that of 36 vent valves (2 per circulator for the brake and 2 per circulat.or for the neal).seven (7) were leaking. The valven were repaired and checked again to ensure that each valve is capable of preventing inadvertent releasing of the seal or brake. Analyzing the brake and seal piping and controls it is advisable that we do not isolate the scal release ]inc. The control room operator would have no indication the seal had not been released and could possibly attempt to rotate the circulator with the brake and seal applied.

FAILURE DATA /

SIIIILAR REPORTED OCCURRE"CES :

Abnormal occurrence 50-267/74/13 dealt with the inability of'"A" helium circulator static seal to remain actuated. A ruptured actuating bellows was the cause of this Abnormal Occurrence.

PROGRATtATIC IiPACT:

None CODE IMPACT:

None s s 1

' ' ~

,6,i

'i Y%

Recomn6nded:

11. Larry Brey hLn _ Approved: f', . ,'- j, u .- s- d'\ gy k ,

i Superintendent-Operation -Frederic C. Swart s \ / upt.

S Nuclear Production Fort St. Vrain Nuclear Fort'St. Vrain-Nuclear Generating Station Generating Station r

o

• DI C.TPIEttr 10'IS

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o Unu r.ual Events and Abnoi ra al U nu sual Operating Monthly occurience Occurrence Cost Iette r Teports I:cpot t r. Ferottai f.d f r e e.ec San Fran:Isco 0.,erations Of fice ERDA In3 trodway Oakland, California 94612 2 2 --

Attu: Manager . . 4 Finance & B+1A ct { g -

Calif. Patent Crcup Division of 3ca: tor Research and 11evelopmen t ERDA Washington, D. C. 205/5 4

1 1 -

1 Attn Director - - 1 -

Asst. Dir. for 1.MTER Pregrams -

2 2 2 Asst. Dir. for Cas CoolcJ Reactor Projcet -

Asst.. Dir, for Engrg. and Technology } l 1 1 1 1 Asst. Dir. for Reactor Safety 1

ERDA -SCRPO-SD P. O, tax S1325 San Diego, California 92138 I l W. Soule', Project Engr.

11bA -SCRF0 P. O. Bex 1446 Canoga Park, California 91304 .

1 2 1 Address - Director 1ctter ++ EnDA -SCRPO to +* P. O. Eax 1446

++ Canoga Park, California 91304

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3 3 Technical Inferr.ation Center FRDA .

P. O. box 62 Oak Ridg'e, Tennessee 37830 Jol n W. Landis, Frealdent, Power Systers Co. 30 10 2 Cencral Atomic CcDFany P. O. 1,ox 51603 San Diego, California 92138 Earbara 011ck 1 1 1 1.ob Clark 1 R. Valker 1 1 F. Svart 1 1 1

1. Erry 1 1

p. Kmigert. I r 11111 3 F. ?!at hie 1 W. UillynrJ l 3

p. Alc unaler 1 J. 1.iebrit 1 K. Stannard 1 IT.C, Direc tor of Ret.ulationc. Washingten,b.C. {

, ,,a o (copy of Ibwand 1ctter & xcg 1 1 1 (Chatrnan NFSc) 0:-car 1.ce Centrol Eoon 3

p. Mai er.t.curg 1

}: . 1bward 3 (lettei) copy of let ter to Cl3 R. Ayner (fl'lC la t t cr) 1 I 1'hiladelphia Electric Ceopany M. J. Corney 1 1

2 301 f t.u ket St. . 10RC Cot el t t re Philadciphia, Pa. 18101

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