05000338/LER-1981-090, Updated LER 81-090/99X-1:on 811214,annunciators for 20.2-hertz & 25.4-hertz Vertical Axis Channels of Containment Mat Response Spectrum Recorder Illuminated & Could Not Be Reset.Cause Unknown.Unit to Be Replaced

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Updated LER 81-090/99X-1:on 811214,annunciators for 20.2-hertz & 25.4-hertz Vertical Axis Channels of Containment Mat Response Spectrum Recorder Illuminated & Could Not Be Reset.Cause Unknown.Unit to Be Replaced
ML20054E394
Person / Time
Site: North Anna Dominion icon.png
Issue date: 06/04/1982
From: Cartwright W
VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20054E392 List:
References
LER-81-090-99X, LER-81-90-99X, NUDOCS 8206110168
Download: ML20054E394 (3)
v • d • e


LER-2081-090, Updated LER 81-090/99X-1:on 811214,annunciators for 20.2-hertz & 25.4-hertz Vertical Axis Channels of Containment Mat Response Spectrum Recorder Illuminated & Could Not Be Reset.Cause Unknown.Unit to Be Replaced
Event date:
Report date:
3382081090R00 - NRC Website
v • d • e

text

bPDATM REPORT: PREVIOUS REPORT DATE 01-21-82

, U.3. NUCLEAR REGULATORY COMMISSION LICENSEE EVENT REPORT CONTROL BLOCK /_/ / / / / / (1) (PLEASE PRINT OR TYPE ALL REQUIRED INFORMATION)

/0/1/ /V/A/N/A/S/1/ (2) /0/0/-/0/0/0/0/0/-/0/0/ (3) /4/1/1/1/1/ (4) / / / (5)

LICEhSEE CODE LICENSE NUMBER LICENSE TYPE CAT RC n/ (6) /0/5/0/0/0/3/3/8/ (7) /1/7/1/4/8/1/ (8) /0 /6 /0 /4 /8 /2 / (9)

DOCKET NUMBER EVENT DATE REPCRT DATE EVENT DESCRIPTION AND PROBABLE CONSEQUENCES (10)

/0/2/ / On December 14, 1981, with the Unit operating at 100% power, the annunciators /

/0/3/ / _for the 20.2 hertz and 25.4 hertz vertical axis channels of the containment /

/0/4/ / mat response spectrum recorder illuminated and could not be reset. On April 28, /

/0/5/ / 1982, the containment operating level triaxial time-history accelerograph was /

/0/6/ / inoperable because the acceptance criteria of its surveillance test could not be /

/0/7/ /_ met. This is reportable pursuant to T.S. 3.3.3.3 and 6.9.2.c. The health and /

/0/8/ / safety of the general public were not affected. /

SYSTEM CAUSE CAUSE COMP. VALVE CODE CODE SUBCODE COMPONENT CODE SUBCODE SUBCODE

/0/9/ /1/F/ (11) /X/ (12) /Z/ (13) /1/N/S/T/R/U (14) /E/ (15) /Z/ (16)

SEQUENTIAL OCCURRENCE REPORT REVISION LER/R0 EVENT YEAR REPORT NO. CODE TYPE NO.

(17) REPORT NUMBER /8/1/ /-/ /0/9/0/ / / /9/9/ /X/ /-/ /1/

ACTION FUTURE EFFECT SHUTDOWN ATTACHMENT NPRD-4 PRIME COMP. COMPONENT TAKEN ACTION ON PLANT METHOD HOURS SUBMITTED FORM SUB. SUPPLIER MANUFACTURER

/Z/ (18) /D/ (19) /Z/ (20) /Z/ (21) /0/0/0/0/ (22) /Y/ (23) /N/ (24) /A/ (25) /E/2/5/9/ (26)

CAUSE DESCRIPTION AND CORRECTIVE ACTIONS (27)

/1/0/ / The cause of the malfunctions are unknown at the present time. The containment /

/1/1/ / mat triaxial response spectrum recorder channels and the triaxial time-history /

/1/2/ / accelerograph will be replaced or repaired during the present refueling outage. /

/1/3/ / refueling outage. /

I /1/4/ / /

FACILITY METHOD OF i STATUS  % POWER DISCOVERY DESCRIPTION (32)

/1/5/ /1/0/0/ (29) / OTHERNA STATUS/ ( } DISCOVERY / Operator-Observation /

/E/ (28) /A/ (31)

ACTIVITY CONTENT l RELEASED OF RELEASE AMOUNT OF ACTIVITY (35) LOCATION OF RELEASE (36)

( /1/6/ /Z/ (33) /Z/ (34) / NA / / NA /

l PERSONNEL EXPOSURES NUMBER TYPE DESCRIPTION (39)

/1/7/ /0/0/0/ (37) /Z/ (38) / NA /

PERSONNEL INJURIES l NUMBER DESCRIPTION (41)

/1/8/ /0/0/0/ (40) / NA /

, LOSS OF OR DAMAGE TO FACILITY I

TYPE DESCRIPTION

/1/9/ /Z/ (42) / NA /

l PUBLICITY

ISSUED DESCRIPTION (45) NRC USE ONLY

! /2/0/ /N/ (44) / NA /////////////

NAME OF PREPARER W. R. CARTWRIGHT PHONE (703) 894-5151 l

, 8206110168 820604 l PDR ADOCK 05000338

S PDR

a .

UPDATE REPORT: PREVIOUS REPORT DATE 01-21-82 Virginia Electric and Power Company North Anna Power Station, Unit No. 1

Attachment:

Page 1 of 2 Docket No. 50-338 b Attachment to LER 81-090/99X-1 Description of Event i

On December 14, 1981, with Unit 1 at 100% power, the containment mat response spectrum tecorder indicated alarms on the vertical axis at frequencies of 20.2 and 25.4 Hz. These alarms indicated an amplitude of

> .054 and .042g respectisely; however, there were no alarms for > 0.077 and .060g in the same axis and frequencies. The alarms would not" reset.

On s.pril 28, 1982, the containment operating level time-history accelero ;raph was inoperable because the acceptance criteria of its surveillance test could not be met. The surveillance test, 1-PT-39.2 failed because the operating level accelerometer natural frequency tests were out of tolerance in all 3 directions (transverse, longitudinal and vertical).

+ The containment mat response spectrum recorder is manufactured by-Engdahl and the triaxial time-history accelerograph is made by Kinemetries, (Model SMA-3).

Probable Consequences of Occurrence j

The operability of the seismic instrumentation ensures that suffi-cient capability is available to promptly determine the magnitude of a seismic event and evaluate the response of those features important to safety. This capability is required to permit comparison of the men-i sured response.to that used in the design basis for the facility to-determine if plant shutdown is required pursuant to Appendix "A" of 10 CFR Part 100. The instrumentation is generally consistent with the recommendations of Regulatory Guide 1.12, " Instrumentation for Earth-quakes,"' April 1974. ,

j The alarms are believed to be due to an equipment malfunction.

i None of the other 10 frequencies for vertical axis alarmed nor were any

! of the 12 frequencies for the north-south or vertical axis alarmed at.

the same time. There was no effect on the public health and safety.

Cause of F 2nt i

The cause of the alarm and failure of the surveillance test is

! unknown. Containment entry to investigate this problem is not practical with the unit at power.

Immediate Corrective Action An attempt was made to reset the alarm. The problem was verified to originatc from the field sensor inside the containment.

i

. , . , . , . . . , , . , -m-,_-., -, - . , , , - , , - ,-v. - , - , , _ - . - ,

. ~

Attachment:

Page 2 of 2 Scheduled Corrective Action The containment mat response spectrum recorder and the triaxial time-history accelerograph will be replaced during the present refueling outage.

Actions Taken to Prevent Recurrence No further action is required.

Generic Implications There are no generic implications.

k

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