ML19350A699

Forwards IE Circular 81-03, Inoperable Seismic Monitoring Instrumentation. No Response Required

ML19350A699
Person / Time
Site:	Perkins, Cherokee
Issue date:	03/02/1981
From:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
To:	Dail L DUKE POWER CO.
References
NUDOCS 8103160677
Download: ML19350A699 (1)

Text

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UNITED STATES I\\

NUCLEAR REGULATORY COMMISSION 3.,p,.. g ' %

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L. C. Dail, Vice President co Design Engineering P. O. Box 33189 Charlotte, NC 28242 Gentlemen:

The enclosed IE Circular flo. 81-03 is forwarded for your information. No written response to this Circular is required. If you have any questions related to this matter, please contact this of fice.

Sincerely, K7' Dk

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-a er-James P. O'Reilly Director

Enclosures:

1.

IE Circular No. 81-03 2.

List of Recently issued IE Circulars cc w/ encl:

J. T. Moore, Project Manager 8103160 0

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SSINS No.

6E30 Accession 40.

2003220271 IEC 81-03

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• J UNITED STATES

'3 NUCLEAR REGULATCRY CCMMISSICN OFFICE OF INSPECTION AND ENFORCEYENT WASHINGTON, D.C.

20555 March 2, 1981 IE Circular No. 81-03: INOPERABLE SEISMIC MONITORING INSTRUMENTATION Descriotion of Circumstances:

On November 8, 1920, an earthquake occurred off the coast near Eureka, California.

The earthquake was reported to have a magnitude of 7.0 on the Richter Scale at the epicenter, approximately 25 to 75 miles from the Humboldt Bay Power Plant facility.

There were 12 separate seismic events above a magnitude of 3.5 that occurred within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of the earthquake, the largest event measuring 5.2.

Reported damage to structures included several houses that were moved off supporting posts, various chimneys that were knocked down, one highway overpass that collapsed, and unspecified damage that occurred at two pulp mills.

There were three potentially different sources of plant response data: three sets of magnetic tape triaxial accelograph recorders; three sets of triaxial film recorders (passive device); and one set of triaxial response spectrum recorders (passive device). A review of the records from these instruments indicated the following: the magnetic tape triaxial recorders did not produce useful records due to a degraded low-voltage power supply in the recording system (previously scheduled for routine servicing one week after the earthquake);

a buildup of dirt and dust appeared to make inoperable six of the nine film recorders (the readings from the other three are considered highly unreliable and were not obtained from the saine set of triaxial recorders); the triaxial response spectrum recorder was the only instrument believed to produce reliable data.

On January 24, 1980, an earthquake measuring 5.5 on the Richter Scale occurred about 10 miles north of Lawrence Livermore Laboratory (near San Francisco, California).

Numerous aftershocks also occurred with one measuring 5.2 on Jar.uary 26.

The damage to civil structures was consicered minor.

Rancho Seco Nuclear Plant, located approximately 45 miles northeast of the earth-quake area, reported no physical damage, although plant personnel felt slight building motion.

Rancho Seco was shutdown for refueling during these earthquakes.

During this period, the electrical seismic instrumentation system was inoperable because portions of the system were out for calibration.

For the other instruments, power was not being supplied due to electrical cable problems. Whether the seismic Instrumentation would have activated or not is unclear because the U.S. Geological Survey equipment close to the site did not trigger.

Records from a passive recorder showed peak accelerations from 1 to 1.5 g and 0.1 g

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IEC 81-03 4

March 2, 1981 Page 2 of 3 for the January 24 and 26 events respectively, which are in excess of values which might be attributed to the seismic event. These indications are not believed to be accurate values since the recorder was in an area in which it could be easily jarred by personnel.

An earthquake measuring 3.G to 4.1 on the Richter Scale occurred about 15 miles from the Maine Yankee site on April 17, 1979.

Personnel in the control room felt the earthquake motion, but it was not felt by others inside the containmenc.

An inspection of the strong-motion accelographs (Kinemetrics SMA-1) on April 19, 1979 revealed that one instrument was inoperable apparently because leakage of corrosive fumes f, rom the rechargeable batteries destroyed the battery connection.

Inspection of the seismic instruments on August 1, 1979 again revealed the corrosion problem as found before but occurring on both instruments.

Based on this, a shorter inspection interval was initiated.

Recent discussions with the manufacturer's representative indicate that the battery corrosion problem appears to be limited to the sMA-1 units because the SMA-2 and SMA-3 units have not exhibited a corrosion problem.

Those facilities that may have SMA-1 units include Turkey Point Unit 3, Pilgrim, Maine Yankee, Vermont Yankee, Point Beach Unit 1, Fort St.

Vrain, and Browns Ferry Unit 1.

The experiences at the Humboldt Bay, Rancho Seco, and Maine Yankee facilities are of concern because, if a significant earthquake had occurred, important data relating to the plant response would not have been obtained.

The experiences point out that (1) calibration or testing of the seismic instrumentation should not disable a major portion of the seismic instrumentation system for long periods of time; (2) the necessity for periodic surveillance and calibration of the entire seismic monitoring system; (3) the necessity to assess the adequacy of the surveillance / calibration interval; and (4) the necessity to detect those areas where accidental impact or high background vibrations may mask the actual seismic response.

In addition, Licensee Event Reports (LERs) submitted to the NRC have revealed various problems relating to seismic instrumentation.

The problems involve not only the electrical time-history instrumentation, but also the passive peak acceleration recorders.

A description i

of the problems is enclosed.

Note that the first problems identified in l

Attachement 1 could have prevented the recording of the plant seismic response l

if a significant earthquake had occurred.

The remainder are instances of less significant malfunctions.

The requirements for seismic instrumratation are described in Appendix A to 10 CFR Part 100 and Regulatory Guide 1.12.

The instrumentation serves l

to enable a prompt review of the actual seismic response of plant features important to safety in comparison with that used as the design basis.

This information can be used to determine whether a plant should be shutdown, or can continue to be safely operated, and to permit appropriate, timely I

action.

If an earthquake were to occur near a nuclear facility, the most l

useful information of the plant's response would be from the onsite seismic instrumentation.

Evaluation of the plant response due to a seismic event l

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e IEC 81-03 March 2, 1931 Page 3 of 3 and evaluation of continued operation of the facility would be difficult without accurate and reliable data.

Based on the above discussion, the following action is reccmmended.

Recommended Action for Holders of Coerating Licenses and Construction Permits:

It is recommended that holders of operating licenses and construction permits review for applicability the specific items presented in the " Description of Circumstances" and the enclosure to the Circular.

It is further reccmmended that the surveillance testing and calibration programs for the seismic instru-mentation system be reviewed and revised as necessary to detect and prevent the malfunctions described herein and to limit the potential for having or making the entire seismic monitoring system (active and passive components) inoperable during all plant modes of operation.

No written response to this Circular is required.

If you require additional information regarding these matters, please contact the Director of the appropriate NRC Regional Office.

Attachments:

1.

Seismic Instrumentation Malfunctions 2.

Recently Issued IE Circulars i

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'j IEC 81-03 March 2, 1931 SEISMIC INSTRUMENTATION MALFUNCTIONS PLANT LER NUMBER /

EVENT DESCRIPTION CCCUMENTATICN Beaver Valley Power 78-028 Magnetic tape recorder Station, Unit 1 (Teledyne Geotech Model MTS-100) was found inoperable during surveillance test; replaced with new instrument D.C. Cook Nuclear Plant, 75-56 One channel was found Unit I during surveillance testing to have a severe amplifier balance shift; the amplifier board was replaced 76-19 Movable masses on the peak recording acceleremeters were against the stops; the units were replaced; initiated shortened surveillance interval 76-50 Cassette tape (Kine-metrics) on monitoring system was found stick-ing during surveillance l

testing; the sticking l

tape was replaced l

Davis-Besse Nuclear 77-13 Spurious activation of Power Station seismic trigger: unit l

was replaced 79-111 Excessive noise in recorded tape prevented reading of accelerometer traces during surveillance test (Teli iyne-Geotech Model 37200); part of problem was due to one lead of AC input line on playback monitor was not connected L

o IEC 81-03 j

March 2, 1931 PLANT

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LER NUMBER /

EVENT DESCRIPTICN COCUMENTATION Patch Nuclear Plant, Letter from Georgia One channel of the Unit 1 Power to NRC dated Triaxial Time-History 6/25/80 Accelerometer (Kinemetrics) had shifted its sensiti-vity by 47% and natural frecuency by 12%

Humboldt Bay NRC Reconnaissance Magnetic tape time-Power Plant Report dated 1/19/81 history accelerometers (TERA Technology) were found inoperable due to a degraded low voltage power supply; 6 of 9 film recorders (TERA Technology) were inoperable because of dirt and dust buildup Maine Yankee Inspection Report Corrosion of connec-Atomic Power 50-309/79-11 tions to the batteries Plant on Kinemetrics SP.A-1 units made the units inoperable; increased testing frequency

nitiated Rancho Seco Nuclear Inspection Report Seismic monitoring Generating Station 50-312/80-03 instrumentation was inoperable due to calibration and power supply problems with electrical cable; passive accelerometers placed in area susceptible to impacts by passing traffic t._

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IEC 81-03 March 2, 1981 PLANI LER NUMBER /

EVENT DESCRIPTION DOCUMENTATION Less Signif1 Tnt Occurrences -

Beaver Valley Power 76-53 Control room seismic alarm Station 78-040 indicated spuriously due to misaligned reed switches; the recording scribes on the Engdahl response spec-trum recorders remained operable; the reed switches were adjusted Calvert Cliffs Nuclear 77-79 The motor on the seismic Plant, Unit 1 tape playback unit (Kinemetrics Model No.

SMP-1) was found sticking; the motor was replaced North Anna Power 78-060 Alarms from the (Engdahl)

Station, Unit 1 78-118 response spectrum recorders indicated spuriously on four separate occasions Three Mile Island 78-002 A defective recording Nuclear Station, plate was found in the Unit 2 spectrum recorder; the plates were replaced i

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IEC 81-03 March 2, 1981 RECENTLY ISSUED IE CIRCULARS Circular Date of No.

Subject Issue Issued to 81-02 Performance of NRC-Licensed 2/9/81 All power reactor Individuals While on Duty facilities (research

& test) with an OL or CP 81-01 Design Problems Involving 1/23/81 All power reactor Indicating Pushbutton facilities with Switches Manufactured by an OL or CP Honeywell Incorporated 80-25 Case Histories of 12/5/80 All radiography Radiography Events licensees 80-24 AECL Teletherapy Unit 12/2/80 All teletherapy Malfunction licensees 80-23 Potential Defects in Beloit 10/31/80 All power reactor Power Systems Emergency facilities with Generators OL or a CP 80-22 confirmation of Employee 10/2/80 All holders of a Qualifications power reactor OL or CP architect-engineering companies and nuclear steam system suppliers 80-21 Regulation of Refueling 9/10/80 All holders of a Crews power reactor OL or CP 80-20 Changes in Safe-Slab Tank 8/21/80 All Part 50 and Part Dimensions 70 fuel facility licensees 80-19 Noncompliance with 8/26/80 All medical licensees License Requirements for Medical Licensees 80-18 10 CFR 50.59 Safety 8/22/80 All power reector Evaluations for Changas to facilities with an Radioactive Waste Treatment OL or CP Systems OL = Operating Licenses CP = Construction Permit