ML20085L788

AO 50-267/74/24A:on 741222,static Seal on Helium Circulator a Released During Removal of Temporary Jumpers.Caused by Jumper Contact W/Station Ground

ML20085L788
Person / Time
Site:	Fort Saint Vrain
Issue date:	04/16/1975
From:	Brey H PUBLIC SERVICE CO. OF COLORADO
To:	Howard E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML20085L789	List: ML20085L788 ML20085L790
References
AO-50-267-74-24, NUDOCS 8311020450
Download: ML20085L788 (4)

Text

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.t Public service company ce cdlende P. O. Box 361, Platteville, Colorado 80651 April 16, 1975 s 3,i_ Il N

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Mr. E. Morris lioward, Director Nucicar Regulatory Coc: mission

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Region IV "

MO(g , .e' e' Office of Inspection and Enforectient Y 611 Ryan Plaza Drive .

Suite 1000 Arlington, Texas 76012 REF: Facility Operating License No. DPR-34 Docket No. 50-267

Dear Mr. Howard:

Enclosed please find a copy of Abnormal Occurrence Report No. 50-267/74/24A, Final, submitted per the requirements of the Technical Specifications.

Very truly yours, hu W

11. Larry Brcy \

Superintendent-Operations Fort St. Vrain Nucicar Generating Station HLB:11 cc: Mr. Angelo Ciambusso 3

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REPORT DATE: January 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 OCCURRENCE:

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.

CONDITIONS PRIOR TO OCCURRENCE: Steady State Power Routide Shutdown Hot Shutdown Routine Load Change A Cold Shutdown X other (specify)

Refueling Shutdown Plant essentially shut down follow-Routine Startup inn initial performance of RT-241 (Feedwater system testing).

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

Power PTR 0 FHith ELECT. O MWe Secondary Coolant Pressure O psig Temperature ~ N/A 'F Flow N/A #/hr.-

Primary Coolant Pressure 25 - psig Temperature- 101 'F Core Inlet 101 *F Core Outlet Flow 0 -f/hr.

Pags 2 O

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. DESCRIPTIO!! 0F

. OCCURRENCE: -

The static seal on C-2101 helium circulator was possibly releaned while replacing plant protective system codules and jumpers previously required to run RT-241 (initial filling of the etcan generators and feeduater control system test).

There are tuo seal release valves in series. A fuse blown uhile removing the junpers caused one of those valves to open. Buffer-nidhuffer instrumentation indicated flou up the circulator shaf t implying that the remaining cchl'rcicase valve is leaking. ,

The normal buffer helium cystem was placed on t'hc circulator to prevent any priuary coolant J oakage.

Analycis of the primary coolant taken on December 20, 1974 indicated no detectabic gamma activity, therefore an accidental release of primary coolant would not have reprencuted a banard to plant personnel or the public. A continuous air monitor located at the PCRV support ring indicated background radiation levc]n. An analynis of prinary coolant on Decenber 23, 1974 indicated no increase in contaminants. g APPARENT CAUSE .

OF OCCURRENCE: 1 Design Unusual Service Cond.

Including Environnent llanufacture X Component Failure Installation /Const. Other (cpecity)

X Operator Procedure Uhile reinoving a jumper acror.s the "A" Jogic circulator brake and seal interlock contacts of C-2101, the jucper apparently contacted station ground resulting in a blown fuse. Thin de-energized a relay whose contacta hold the appropriate brake and scal valveu closed or open as required.

Because of redundent valving in the nyt, tem, valve HV-21191-3 had to be leaking for the seal release to occur.

ANALYSIS OF OCCURRENCE:

Blowing a fuse in the brake and seal circuit should not in itself release the circulator ccal. There are tuo series brake and seal relcane valves and the blown fuse vauld ,nly affect one of the ncal and one of the brake relcanc valves.

The seal and brake helfun pressure supply valven are in parallel and are also ceparately fused, but the blown fuse would effect one brake and one seal cupply valve,

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, . CORRECTIVE

, i ACTION:

A check was made 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 16 vent valves (2 per circulator for the brake and 2 per circulator for the seal) seven (7) were leaking. The valves 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 is.olate the seal release line. 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 /

SIMILAR REPORTED OCCURRENCES:

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.

PROGRAt.DLATIC IMPACT:

None CODE IMPACT:

None g.

Recomended: -

NU -W Approved: .?g pc s- d' 5; v'I H. Larry Brey i ( rederic E. Swart Superintendent-Operations [@ Supt.NuclearProduction Fort St. Vrain Nuclear Fort St. Vrain Nuclear Generating Station Generating Station e

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