ML20151A670

IE Bulletin 80-17 Suppl 4, Failure of Control Rods to Insert During Scram at Bwr

ML20151A670
Person / Time
Issue date:	12/18/1980
From:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE)
To:
References
IEB-80-17-S04, IEB-80-17-S4, NUDOCS 8011040252
Download: ML20151A670 (5)

Text

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SINS No.:

6820 Accession No.:

60110 4 OA5'A UNITED STATES IEB 80-17 Sup. 4 i

NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION A!O ENFORCEMENT

. WASHINGTON, D.C.

20555 December,18, 1980 IE Supplement 4 to Bulletin No. 80-17:

FAILURE OF CONTROL RODS TO INSERT DURING A SCRAM AT A BWR NRC staff evaluation of failures of the continuous monitoring system (CMS) for the scram discharge volume (SDV) at an operating BWR has identified the need for licensee actions in addition to those requested by IE8 80-17 and Supplements 1-3.

The purpose of these acticns is to provide assurance that the CMS has been tested to demonstrate operability as installed, remains operable during plant operation, and is periodically surveillance tested to demonstrate continued operability.

The occurrence of CMS failures at Dresden Nuclear Power Station was discussed in IE Information Notice 80-43, which was issued on December 5,1980 to those operating BWR's with CMS recently installed.

Subsequently, investigation into the cause of the failure to receive the alarm with the 50V essentially full revealed several items which required correction, including:

1.

Excess portions of transducer cable were placed in physical positions 4

which would incfease external noise sensitivity.

2.

The UT transducers were not placed in a physical position to optimize system sensitivity.

3.

A certain amount of "cross-talk" was occuring between redundant trans-ducers located a few feet apart on the game run of 4" pipe.

Station and vendor personnel shortened and rerouted transducer cables to improve Vendor specialists optimized transducer placement and noise rejection.

synchronized both transducers to the same ultrasonic instrument internal clock Following to minimize cross-talk and improve signal to noise characteristics.

these actions the CMS appeared to function properly.

Further difficulties were encountered when apparently minor quantities of water leaked into the SDV as a result of control roc drive scram valve maintenance activities and minor scram outlet valve leakage.

It appears that the trans-ducers are located on a section of SDV piping which forms a local low point.

Accordingly, small amounts of water can accumulate to a depth, which triggers the high level alarm (at 1-1/4") before the water drains to the instrument The licensee in conjunction with the NSSS vendor, performed a unit volume.

specific analysis for a conservative high alarm setpoint and reset the alarm The system now appears to function properly.

A five second point to 2-1/2".

alarm time delay was also installed to aid in rejecting spurious alarms.

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.IEB 80-17 een. 4 December i1980

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-Potential malfunction modes which are still o' concern are:

1.

The capability of the CMS to adequately determine. level of water for the entire range of. depths which may occur daring slow and rapid fill condi-tions, that is, beam penetration capability.

2.

The potential for loss of transducer sensitivity during periods of rapid flow, or when the water being detected is turbulent or mixed with entrained air or steam bubbles.

The ability of the CMS installed in your faci'.ity to operate in resp'ect to these concerns should be considered in the preparation of your response to this bulletin.

The following actions are requested in addition to those specified in IE Bulletin 80-17 and Supplements 1 througn 3.

Actions to be Taken by Licensees of Operatina BWR's Using CMS 1.

Bench Test of CMS Make available the following information which describes the CMS design and the bench tests which have been performec to demonstrate system operability and sensitivity:

(a) System description including a scne atic of the apparatus and associated electronics.

(b) Type of sensing device and characte-istics (include response characteristics versus temperature).

(c) Calibration criteria, including trar.smission losses.

(d) Training and testing of personnel performing the calibration test.

Items a through c above may be referencec by the licensee if the information has been submitted to the NRC by the equipment manufacturer.

2.

Operability Test of CMS Prior to conducting the operability test. verify that the CMS on the 50V is installed and calibrated in accordance with the m dor recommendations.

In order to provide assurance of operability of the CMS, if not already performed conduct an operability test wi:nin 14 days of the date of this bulletin.

In this test, inject a sufficient amount of water into each SDV header to determine that the ultraso-ic transducers are adequately coupled to the SDV piping and that the trip alarm function of the CMS will perform satisfactorily.

The test may be performed by single (multiple) rod scram tests while operatirg.

No water may be introduced into the SDV header while the reactor is operating except using the scram function.

Independent luel measurement must be used to verify CMS operation and proper calibration.

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I 80-17 Sup. 4 December 18, 1980 Page 3 of 4 f

3.

Interim Manual Surveillance In the interim 14-day period before the operability test is completed, perform a manual surveillance for the, presence of water in the SDV at least once per shift and after e.:ch reactor scram.

In order to provide assurance that manual surveillance can detect water accumulation in the SDV, verify that the method and the operator have been qualified by testing which uses or simulates the SDV piping and has the ability to detect different levels of water in the SDV.

Surveillance of SDV manual measurement techniques should be done before completion of the operability test described in Item 2 above.

4.

Full Test of CMS to be Conducted Durino a Planned Outage During a planned outage within six months, perform a full CMS test using the SDV headers:

(a) Admit water into the SDV to establish fill rates for several (not less than three) in-leakage flow rates.

The in-leakage rates should range from approximately the minimum which results in water accumula-tion in the SDV to a full scram.

(b) Establish and record the response of the CMS indication and alarm functions f*om the trip level to a full SDV.

Provide criteria for replacement or adjustment when exceeding design specifications of the system.

(c) Verify by independent measurement that the alarm initiates at the proper levei setpoint.

5.

Operability of CMS During Reactor Operation The CMS shall be operable prior to reactor startup and during reactor operation.

If tne CMS becomes less than fully operable, within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> perform a manual check for water in the SDV and institute procedures for a manual check of the SDV each shift and following scram until the CMS is fully operable.

When not fully operable, the CMS should be used to the extent practical in addition to the manual cnecks.

If the CMS is not operable within 7 days, the frequency of the manual check should be increased to once every 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />.

If the CMS is not operable within 30 days the plant shall be shutdown.

To demonstrate centinued operability of the CMS during reactor operation, perform periodic surveillance tests for operability of the CMS.

For these periodic surveillance tests, test as inuch of the CMS as practical during reactor operation without injecting water in the SDV.

Establish criteria for repair or replacement when the system cesign criteria or estimated service life limitations are exceeded.

The frequency of these periodic surveillance checks should be determined by the licensee.

IEB 80-17 Np. 4

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These periodic surveillance tests snould include the following:

t (a) determination that the response and power output of the transducer has not degradec; (b) visual inspection for adequate ccndition of the transducer to SDV coupling material; and (c) a calibration check of the electronics te assure alarm initiation in the control room.

Water should be periodically injected into the SDV to perform a CMS operability and calibration check similar to that specified in Item 2 above. This check should be performed semiannually and during startup after plant cutages where maintenance operations may have taken place near to CMS equipment.

6.

Operatino Procedures Develop procedures for operation, periodic testing and calibration of the CMS and for repair or replacement when system design specifications are exceeded.

Develcp procedures for the calibration und use of the hand held UT device in the event of a malfunctioning CMS.

Notify the NRC before changing the established CMS alarm level setpoints.

Licensees of all operating BWRs with a CMS shall provide the information requested in Item 1 and shall submit a report summarizing action taken in response to each of the above items within 45 days of the date of this Bulletin Supplement.

Accordingly, you are requested to provide within 45 days as specified above, written statemer.ts of the above information signed under oath or affirmation under provisions of Section 182a of the Atomic Energy Act of 1954.

Reports shall be submitted to the Director of the appropriate NRC Regional Office and a copy forwarded to the Director, NRC, Office of Inspection and Enforcement, Washington, D.C.

20555.

This request for information was approved by GA0 under a blanket clearance number R0072 which expires November 30, 1983.

Comments on burden and duplication should be directed to the U.S. General Accounting Office, Regulatory Reports Revie, Room 5105, 441 Eighth Street, N.W., Washington, D.C.

20548

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.)IEB80-17Sup.4 i

December 18, 1980 RECENTLY ISSUED IE BULLETINS Bulletin No.

Subject Date Issued Issued To 80-24 Piever?. ion of Damage 11/21/80 All power reactor Due to Water leakage facilities with Inside Containment OL or CP (Octooer 17, 1980 Indian Point 2 Eventi 80-23 Failures of Solenoid 11/14/80 All power reactor Valves Manufactured by facilities with Valcor Engineering OL or CP Corporation 80-22 Automation Industries, 9/11/80 All radiography Model 200-520-008 Sealed-licensees Source Connectors 80-21 Valve yokes supplied by 11/6/80 All light water Malcolm Foundry Company, Inc, reactor facilities with OLs or cps Supplement 3 Environmental Qualification 10/24/80 All power reactor to 79-10B of Class 1E Equipment facilities with an OL Supplement 2 Environmental Qualifica' ion 9/30/80 All power reactor to 79-01B of Class IE Equipment facilities with an OL 80-22 Automation Industries, 9/11/80 All radiography Model 200-520-008 Sealed-licensees source Connectors 79-26 Boron Loss from BWR 8/29/80 All BWR power Revision 1 Control Blades facilities with an OL 80-20 Failures of Westinghouse 7/31/80 To each power Type W-2 Spring Return reactor facility to Neutral Control Switches in your region with an OL or a CP 80-19 Failures of Mercury-7/31/80 All power reactor Wetted Matrix Relays in facilities with Reactor Prctective Systems an OL or CP of Operating Nuclear Power Plants Designed by Combus-tion Engineering OL = Operating License CP = Construction Permit

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December 17, 1980 MEMORANDUM FOR:

B. H. Grier, Director, Region I J. P. O'Reilly, Director, Region II J. G. Keppler, Director, Region III K. V.-Seyfrit, Director, Region IV R. H. Engelken, Director, Region V FROM:

James H.-Sniezek, Director, Division of Resident and Regional Reactor Inspection, IE

SUBJECT:

IE SUPPLEMENT 4 TO BULLETIN 80 FAILURE OF CONTROL RODS TO INSERT DURING A SCRAM AT A BWR The subject document is being transmitted for issuance by FAX or similar cox;unication on December 18, 1980 to all operating GE BWR power reactor facilities except Hatch 1 and 2, Brunswick 1 and 2, Duane Arnold and Big Rock Point 1.

These six BWR's are exempted because they have scram discharge volume designs not subject to the same problems as Browns Faary.

This supplement should be issued for information to these six BWR's and to BWR power reactor facilities with construction permits.

We request inspection verification of licensees' actions to satisfy the bulletin requirements. We also request that Regional UT specialists evaluate acceptability of licensee level instrument function and that RRRI be notified of any exceptions to the bulletin requirements.

We note that it is not clear at this time that the individual (multiple) rod scram tests will provide sufficient water to actuate the high level alarm on the scram discharge volume continuous monitoring system at all plants.

If a single _ rod scram does not provide sufficient water, multiple rods should be

. scrammed to the extent consistent with safe operating practices.

If the multiple rod' scrams ao not provide sufficient water, RRRI should be notified, and the operability of continuous monitoring system evaluated on a plant specific basis.

We are also working with NRR on ways (such as Technical Specifications) to l

further implement some of the bulletin requirements.

If additional information l

is needed or there are additional questions notify the contact listed below.

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CONTACT:

W. R. Mills, IE 49-28180 l

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L Also enclosed are draft copies of the transmittal letters.

James H. Sniezek, Director Division of Resident and Regional Reactor Inspection

Enclosure:

1.

Draft Trensmittal Letter for Action 2.

Draf t Transmittal Letter for Information 3.

IE Supplement No. 4 to Bulletin No. 80-17

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12/9/80 WRMills ELJordan BULL 3(M) 12//7/80 12/// /80

• 4-(Draft letter to the identified GE BWR power reactor facilities with an operating license)

IE Supplement No. 4 to Bulletin No. 80-17:. FAILURE OF CONTROL RODS TO INSERT DURING A SCRAM AT A BWR Addressee:

Enclosed is IE Supplement No. 4 to Bulletin No. 80-17 which requires action by you with regard to your power reactor facility (ies) with an operating license.

In order to assist the NRC in evaluating the value/ impact of each Bulletin on

. licensees, it would be helpful if you would provide an estimate of the manpower expended in conduct of the review and preparation of the report (s) required by the Bulletin.

Please estimate separately the manpower associated with correc-

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tive actions necessary following identificatien of problems through the Bulletin.

Should you have any questions regarding this Bulletin or the actions required by you, please contact this office.

Sincerely, Signature (Regional Director)

Enclosures:

1.

IE Supplement No. 4 to Bulletin No. 80-17 2.

Recently issued IE Bulletins

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(Draft letter to the identified six BWR's with operating' license and to all BWRs in construction)

IE Supplement No. 4 to Bulletin No. 80-17:

FAILURE OF CONTROL RODS TO INSERT

.DURING A SCRAM AT A BWR Addressee:

The enclosed IE Supplement No. 4 to Bulletin 80-17 is forwarded to you for information.

No written response is required.

If you desire additional information regarding this matter, please contact this office.

Sincerely, Signature (Regional 01 ector)

Enclosure:

IE Supplement No. 4 to Bulletin 80-17 l

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