05000267/LER-1981-030, Forwards LER 81-030/03L-0

Forwards LER 81-030/03L-0

ML20004D696
Person / Time
Site:	Fort Saint Vrain
Issue date:	05/22/1981
From:	Warembourg D PUBLIC SERVICE CO. OF COLORADO
To:	Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML20004D697	List: 05000267/LER-1981-030, Forwards LER 81-030/03L-0 05000267/LER-1981-030-03, /03L-0:on 810422,during Normal Operation,Two Pressure Transmitters Were Discovered Indicating Low Pressure.Caused by Instrument Drift.Pressure Transmitters Were Calibr
References
P-81150, NUDOCS 8106090657
Download: ML20004D696 (7)

LER-1981-030, Forwards LER 81-030/03L-0

Event date:
Report date:
2671981030R00 - NRC Website

text

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May 22, 1981 A':M 0 31981" ~ '

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Vrain Unit No. 1

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Mr. Karl V. Seyfrit, Director Nuclear Regulatory Commission Region IV Office of Inspection and Enfr eement 611 Ryan Plaza Drive Suite 1000 Arlington, Texas 76012

Reference:

Facility Operating License No. DPR-34 Docket No. 50-267

Dear Mr. Seyfrit:

Enclosed please find a copy of Reportable Occurrence Report No. 50-267/

81-030, Preliminary, submitted per the requirements of Technical Specifi-cation AC 7.5.2(b)1 and AC 7.5.2(b)2.

Also, please find enclosed one copy of the Licensee Event Report for Reportable Occurrence Report No. 50-267/81-030.

Very truly yours,

%%hw Don Warembourg Manager, Nuclear Production DW/cis Enclosure Q

cc: Director, MIPC S

/ C h 8106090 hh l

01 4- -g OCCI'RAINCE REPORT DISTRI3t, ION T

Nt.mber of Copies Depa rtment o f Energy - - - - - - - - - - - - - - - - - - - - - -, - - - - - -

1 (P Letter)

San Francisco Operations Office Atta: California Patent Group 1333 3 roadway Oakland, California 94612 2

t Dep artmen t o f Ene rgy - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

1 (P Letter)

I

'fr. Glen A.' Newby, Chief HTR 3 ranch Division of Nuclear Power Developmeng Mail Station 5-107 Washington, D.C.

20545

. De par tment o f Ene r gy - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

1 (P Letter)

Atta: Project Manager 110 Vest A Street, Suite 460 San Diego, California 92101 Mr. Ka rl v. S eyf rit, Dire cto r - - - - - - - - - - - - - - - - - - - - - - - - -

h (Original of P Letter Region IV and Copy of LER) office of Inspection and Enforcement Nuclear Regulatory Commission 611 Ryan Plaza Drive i

Suite 1000

. Arlington, Texas 76012 I

Di re c to r - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

1 (P Letter, U R)

Office of Management Information and Program Control U. S. Nuclear Regulatory Cosmission Washington, D.C.

20555 i

Mr. 11 cha rd Phe lp e -

10 (Original of TFLG Letter PSV, CA. Site Representati" plus Two Copter, one Cencral Atemic Company Copy of P I4tter, one P. O. Box 426 Copy of LEP)

Platteville, Colorado 80651 i,

Mr. Sill Lavalee - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

1 (P Letter, LER)

Nuclear Safety Analysis Center 3412 R111 view Avenue P. O. Box 1041.

Palo Alto, California 94303 NRC Resident Site Inspector --------------------------

1 (P Letter, LER) i i

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REPORT DATE:

May 22, 1981 REPORTABLE OCCURRENCE 81-030 ISSUE O OCCURRENCE DATE:

'Aoril 22, 1981 Page 1 of 5 i

FORT ST. VRAIN NUCLEAR GENERATING STATION PUBLIC SERVICE COMPANY OF COLORADO 16805 WELD COUNTY ROAD 19 1/2 PLATTEVILLE, COLORADO 80651

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REPORT NO. 50-267/81-030/03-L-0

[

Preliminary

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1 IDENTIFICATION OF t

CCCURRENCC-Testing of the primary coolant programmed pressure scram revealed that two of the pressure transmitters were out of calibration and could h ve allowed operation with trip setpoints less conservative i

than required by LCO 4.4.1, Table 4.4-1.

l This is reportable per Fort St.

Vrain Technical Specification AC 7.5.2(b)1 and AC 7.5.2(b)2.

EVENT I

DESCRIPTION

See Figure 1.

While performing the monthly calibration check of the r

primary coolant pressure scram channels, plant instru ent personnel l

observed that two of the pressure transmitters 1 were out of calibration in the nonconservati e direction and would have resulted in the pressure switch highs 2 tripping at a higher pressure than allowed by LCO requirements.

he low readings of the pre sure i

transmitters @ would have caused the pressure switch lows 3,

to trip sooner at a higher, more conservative pressure than required.

trips @ and @ are progr mmed by f

The high and low pressure circulator inlet temperature thrAugh an@ auctioneer circuit 4 and a t

bistable setpotnt programmer US or The programmed pressure l

temperature curve is shown in Figure 2.

The low outpoint signal from l

the pressure transmitter could have resulted in the high pressure trips @oc urring above the allowable high pressure curve i

(line A

).

The low pr%s pressure trip curve (line h @ure trips would have occurred above low t

) in a conservative direction.

Although the high pressure trips could have occurred at a value less I

conservative than that established in the Technical Specifications, they would not prevent the fulfillment of the functional requirements of the systems.

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REPORTABLi. CCCURRENCE 81-030 ISSUE O Page 2 of 5 Imtext

CAUSE

DESCRIPTION:

The low pressure signals were due to instrument drift of the cressure transmitter.

CORRECTIVE ACTION The pressure transmitters were calibrated during the procedure and returned to service.

Once a month, on a temporary basis, the pressure transmitter voltage outputs will be checked against reactor pressure to determine if furtaer instrument drift is occurring.

The monthly test will be conducted until the next regularly scheduled surveillance calibration is required or until it is determined that instrument drift is not occurring.

The results will be included in a future supplement report.

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REPORTABLE OCCURRENCE 81-030

' ISSUE 0 Page 3 Of 5 RmR PRESSURE C!RCULATOR INLET TEMPERATURE dh (PROPORTIONAL TO PLANT LOAD)

CHROMEL/CONSTANTAN P.r POTENT 10 METRIC H McCOURES W A M TE TE TRANSOUCER IN WELLS IN PCRV LOWER MEAD

• - -,, INSTRUMENT PENETRATIONS t3 C,-3 TEST

~~

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~~

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MAIN CONTROL 3r 1r 1r ROOM AMPLIFIER AMPLIFIER AMPLIFIER h

0 TH INDICATOR AUCTIONEER BISTABLE SETP0lNT BISTABLE SETPOINT PROGRAMMER (WITH TH TM PROGRAMMER (WITH HIGH AND LOW HIGH AND LOW v

LIMITS)

LIMITS)

OPI

@ ^ SETPolNT SET AT INDICATOR 500 PSIA 1r ir 1r BISTABLE BISTABLE BISTABLE SETPolNT INDICATOR hir v

1r TO PCRV TO LOOP TO SCRAM RELIEF VALVE SHUTOOWN CHANNEL "A" tNTERLOCK AND STEAM /

(2 0F 3)

WATER OUMP CIRCULI (2 0F 3)

CIRCUlTRY Reactor pressure instru:nent, channel (typ. for channels 3&C) t FIGURE 1

s 800 isis i7.7.5...PS.i A!!

UPPER ij;lliGil PRESSUltE:!!

SEIPOlNT

is!;!.

iiljTR.lP CURVE ioog LiHI!

75%

5!!!iii:-

NE 50%

S E T Po l NT::

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^

LlHIT 5

600 s!!!

25%

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E [b

NORiiAL

!!!O)W REACI0It!.!

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oc OPERATING m

!! PRESSURE N

S LOWER PRESSURE jj"h: - :

.li 1.!TR I P CUR,VE b

U 500 SETPOINT CURVE

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LlHIT y

k'y.. LOW PRESSURE l.!!.

ijSCRAM TRIP 100 i:iii

!' B Y P A S S E D B E L O W i!!

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!! 2. 5..%... LO AD 8G El ggg I..iii w'"fi (l!!!

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300 o

=

R

~300 100 500 600 700 800 900 g

i CIRCULATOR lHLET TEMPERATURE (*F) h O

Fig. ~.1-14--Progranuned reactor pressure high-low trip poisite O

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t REPORTABLE OCCURRENCE 81-030 ISSUE O Page 5 of 5 Prepared By:

Asa B. Reed Technical Services Technician t

Reviewed By:

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echnical Services Supervisor Reviewed By:

i Frank M. Ma:nie l

Cperations Manager-

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Approved By:

Mad %

Oon waremoourg u

. Manager, Nuclear Production i

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