ML19350B575
| ML19350B575 | |
| Person / Time | |
|---|---|
| Site: | River Bend  |
| Issue date: | 12/18/1980 |
| From: | Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | Draper E GULF STATES UTILITIES CO. |
| References | |
| GL-80-111, NUDOCS 8103230045 | |
| Download: ML19350B575 (1) | |
Text
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UNITED STATES
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NUCt. EAR REGULATORY COMMISSION REGION IV
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In Reply Refer To:
Dece.::er 15, 1920 i
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Occket Nos. 50-4537IE Su;:olement 4 to Bulletin No. 50-17 50-459/IE Su::plement 4 to Su11etin No. 50-17 i
1 Gulf States Utilities Attn:
Dr. E. Linn Dracer, Jr.
i Vice President-Technology
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P. O. Box 2951 i
i Beaumont, Texas 77704 Gentlemen:
The enclosed IE Su;;plement No. 4 to Sulletin 80-17 is forsarded to you for I
i information.
No written response is required.
If you desire additional infomation regarding this matter, please contact tnis office.
Sincerely,
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'arl V. Seyfrit Director
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Enclosures:
i 1.
IE Sucplement No. 4 i
to Bulletin No. 80-17 2.
List of Recently Issued IE Bulletin
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8103230045
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SSINS No.:
6820 Accession No.:
8006190074 UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
20555 i
IE Supplement 4 to Bulletin No. 80-17 December 18, 1980 Page 1 of 4 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 (RDV) at an operating BWR has identified the need for licensee actions in adsv ion to those requested by IEB 80-17 and Supplements 1-3.
The purpose of these actions 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 j
the cause of the failure to receive the alarm with the SDV essentially full revealed several items which required correction, including:
1.
Excess portions of transducer cable were placed in physical positions which would increase external noiss 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 same run of 4" pipe.
Station and vendor personnel shortened and rerouted transducer cables to improve noise rejection.
Vendor spec;clists optimized transducer placement and synchronized both transducers to the same ultrasonic instrument internal clock to minimize cross-talk and improve signal to noise characteristics.
Following 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 rod drive scram valve maintenance activities and mincr scram outlet valve leakage.
It appears that the trans-ducers are located on a sectton of SDV piping which forms a local low point.
Accordingly, small amounts of water can accumulate to a deptn which triggers the high level alarm (at 1-1/4") before the water drains to the instrument volume.
The licensee in conjunction with the NSSS vendor, performed a unit specific analysis for a conservative high alarm setpoint and reset the alarm-
. point to 2-1/2".
The system now appears to function properly. A five second alarm time delay was also installed to aid in rejecting spurious alarms.
IE Supplement 4 to Bulletin No. 80-17 December 18, 1930 Page 2 of a i
I Potential malfunction modes wnich are still of conce n are:
r 1.
The capability of the CMS to acequately cetermine level of water for the entire range of depths which may occur during slow and rapid fill conci-tions, that is, beam penetration capability.
2.
The potential for loss of transducer sensitivity during periods 'f rapid flow, or when the water being detected is turbulent or mixed with entrained dir or steam bubbles.
The ability of the CMS installed in your facility to operate in respect to these concerns should be considered in the preparation of your response to tnis bulletin.
The following acticns are requested in addition to those specified in IE Sulletin 80-17 and Supplements 1 through 3.
Actions to be Taken by Licensees of Ocerating BWR's Using CMS t
1.
Bench Test of CMS Make available the following information wnich describes the CMS design anc the bench tests which have been performed to demonstrate system operability and sensitivity:
(a) System description including a schematic of the apparatus and associatad electrchics.
(b) Type of sensing device and characteristics (include responsa characteristics versus temperature).
(c) Calibration criteria, including transmission losses.
(d) Training and testing of personnel performint. the calibration test.
Items a through c aoove may be referenced by the-licensee if the information has been submitted to the NRC by the equipment manufacturer.
2.
Ooerability Test of CMS Prior to conducting the operability test, verify that the CNS on tne SDV is installed and calibrated in accordance witn the vendor recommendations.
In order to provide issurance of operability of the CMS, if not already performed, conduct '.n operability test within 14 days of the date of this bulletin.
In this test, infect a sufficient amount of water into each SDV header to dets emine that the ultrasonic transcucers are adequatel, coupled to the SDV piping and that the trip alarm function of the CMS will perform satisfactorily.
The test may oe performed by single (multiple) rod ' scram tests while operating.
No water may be introduced into the SDV header while the reactor is operating except using the scram function.
Independent level measurement must be used to verify CMS operation and proper calibration.
IE Supplement 4 to Bulletin No. 80-17 December 18, 1980 Page 3 of 4 3.
Interim Manual Furveillance In the inte
.r. 14-day period before the operability test is completed, perform a s.. mal surveillance for the presence of water in the SDV at least onct per shift and after each 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 whic'
.3 or simulates the SDV piping and has the ability to detect difictent 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 During a Planned Outaae 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 from 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 level setpoint.
5.
Ooerability of CMS During Reactor Operation The CMS shall be operable prior to reactor startup and during reactor operation.
If the 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 checks.
If the CMS is not operable within 7 days, the frequency of the manual l
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 l
operable within 30 days the plant snall be shutdown.
To demonstrate ;ontinued operability of the CMS during reactor operation, l
perform peri dic surveillance tests for operability of the CMS.
For i
these periodic surveillance tests, test as much of the CMS as practical during reactor operation without injecting water in the SDV.
Establish criteria for repair or replacement when the system design criteria or estimated service life limitations are exceeded.
The frequency of these periodic surveillance checks should be determined by the licensee.
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IE Supplement 4 to Bulletin No. 80-17 December 18, 1980 Page 4 of 4 These perivaic surveillance tests should include the following:
(a) determination that the response and power output of the transducer has not degraded; (b) visual inspection for adequate condition of the transducer to SDV coupling material; and (c) a calibration check of the electronics to assure alarm initiation in the conte:1 rnom.
Water should be periodically injected into the SDV to perform a CMS operat ility and calibration check similar to that specified in Item 2 above.
This check should be performed semiannually and during startup after plant outages where maintenance operations may have taken place near to CMS equipment.
6.
Operating Procedures Develop procedures for operation, periodic testing and calibration of the CMS and for repair or replacement when system design specificaticos are exceeded.
Develop procedures for the calibration and 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 statements 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.(
20555.
This request for information was approved by GA0 under a blanket clearance number R0072 which expires Novamhar 30, 1983.
Comments on burden and duplication should be directed to the U.S. General Accounting Office, Regulatory Reports Review,
- om 5106, 441 Eighth Street, N.W., Washington, D.C.
20548 I
IE Bulletin No. 80-17 Sup. 4 December 18, 1980 RECENTLY ISSUED IE BULLETINS Bulletin Subject Date Issued Issued To No.
79-26 Boron Loss from BWR 8/29/80 All BWR power facilities Rev. 1 control blades with an Operating License (0L) 80-22 Automation Industries, 9/11/80 All radiography Model 200-520-008 sealed licensees sources connectors Sup. 2 Environmental Qualifica-9/30/80 All power resctor to 79-01B tion of Class IE facilities with an Equipment Operating License (OL) or Construction Permit (CP)
Sup. 3 Environmental Qualifica-10/24/80 All power reactor to 79-10B tion of Class IE facilities with an Equipment Operating License (OL) or Construction Permit (CP) 80-21 Valve yokes supplied by 11/6/80 All light water Malcolm Foundry Company, Inc.
reactor facilities holding Operating Licenses (0Ls) or Construction Permits (cps) 80-22 Automation Industries, 9/11/B0 All radiography licensees Model 200-520-008 Sealed-Source Connectors 80-23 Failures of Solenoid 11/14/80 All power reactor facilities Valves Manufactured by with Operating License (0L)
Valcor Engineering or Construction Permit (CP)
Corporation 80-24 Prevention of Damage 11/21/80 All power reactor facilities Due to Water Leakage with Operating License (0L)
Ireide Containment or Construction Permit (CP)
(October 17, 1980 Indian Point 2 Event)
Enclosure
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