ML19331B405
| ML19331B405 | |
| Person / Time | |
|---|---|
| Site: | Hartsville, Phipps Bend  |
| Issue date: | 07/18/1980 |
| From: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | Parris H TENNESSEE VALLEY AUTHORITY |
| References | |
| NUDOCS 8008120060 | |
| Download: ML19331B405 (1) | |
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s'o, UNITED STATES NUCLEAR REGULATORY COMMISSION
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ATLANTA, GEORGIA 30303 In Reply Refer To:
RII:JPO 50-518, 50-519 50-520- 50-521 M 3, 50-55 D Tennessee Valley Authority ATTN:
H. G. Parris Manager of Power 500A Chestnut Street Tower II Chattanooga, TN 37401 Gentlemen:
The enclosed IE Supplement No. I to Bulletin No. 80-17 is forwcrded to you for information. No written response is required. If your desire additional information reprding this matter, please contact this office.
Sincerely, N
O awta_e Ow M
mes P. O'Reilly Di ector
Enclosures:
1.
IE Supplement No. I to Bulletic No. 80-17 2.
List of heently Issued IE Bulletins cc w/ enc 1:
R. T. Hathcote, Project Manager J. F. Cox, Supe: visor, Nuclear Licensing Senion J. E. Wills, Project Engineer H. N. Culver, Chef, Nuclear Safety Review Staff W. P. Kelleghar, Project Manager O
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Accession No.:
UNITED STATES 8006190027 NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
20555 July 18, 1980 IE Bulletin No. 80-17 Supplement No. I FAILURE OF 76 0F 185 CONTROL RODS TO FULLY INSERT DURING A SCRAM AT A BWR Description of Circumstances:
Please refer to IE Bulletin 80-17, issued July 3,1980, for complete details of the initiating event.
Although we are essentially co ifident that the event was caused by water in the Scram Discharge Volume (SDV) system, we do not yet have a complete explanation as to why tie water was present. The best estimate is that some type of blockage existed in &,ent and/or drainage system for the SDV, precluding adequate drainage. To4usure that the SDV is empty, Browns Ferry (BF-3) hrs installed instrumentam w to continuously monitor the water level in the scram discharge volume.
Sud instrumentation is being considered by other plants.
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Since issuam of IE Bulletin 80-17, additional information has been identified.
Specifically:.
a)
At Broter Ferry a discrepancy was found between the "as-built" scram discharp system and the "as-designed" system. An unused one-inch (1") intrument line was found uncapped on the four-inch (4") drain header = the west side (the side whose rods scrammed) scram discharge volume met system of Unit No. 3.
It is believed that this line improvd*he ventinE, and therefore the drain time for that system.
b)
It has het determined that the vent systems on some scram discharge volumes arreonnect with vent headers that are also common with and are conerted to other systems. The interconnected " vent" systems may comin water drained or being drained from those other systems.
This war could potentially affect performance of the SDV. Also, both thvent and drain systems for the scram discharge system may contain ag lengths of relatively small bore piping. Designs specify a verY = dual slope, such that small errors in the "as-installed" pipingsaId result in degraded performance (for example, due to loop aab).
c)
Concear.he been expressed within the NRC Staff regarding potential dela)st:L'st may occur before start of injection of boron into the BWR systas%tna the Standby Liquid Control System (SLCS) when this manual operahtxtion is required. The potential delays could be caused by C
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IE Bulletin No. 80-17 July 18, 1980 Supplement No. 1 Page 2 of 3 unavaliability of the SLCS key which is required to initiate this system, and/or administrative delays which require supervisory' approval before the SLCS can be manually initiated by the control room licensed operator.
In view of the above items, the following actions in addition to those specified in IE Bulletin 80-17 are to be taken by BWR licensees.
A.
Actions to be Taken by BWR Licensees Upon Receipt and to be Reported Within 20 Days of the Date of This Letter:
1)
Provide to the NRC Regional Office an analysis of the adequacy of the "as-built" SDV system and associated vent and drain systems, including any identified design deficiencies.
Include copies of verified "as-built" isometric drawings of the SDV and detailed descriptions of the remainder of the system, verified to be correct, as part of this analysis.
2)
Revise and implement Operating Procedures as necessary to provide clear guidance to the licensed operator in the control room regarding when he should initiate the SLCS without obtaining prior supervisory (S
approval. Provide a description of the implemented procedural
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requirements.
3)
Assur,e that procedures exist and are implemented for specifying remedial action to be taken if water is found in the SDV system at times when it should be free of water.
Provide a description of the implemented procedural requirements.
4)
Revise and implement administrative procedures as necessary to ensure that the SLCS key shall be readily available to the licensed operator in the control room.
Provide a description of the implemented pro-cedural requirements.
5)
Continue daily monitoring of water levels in all scram discharge volumes until continuous monitoring system (s) (discussed in B.1 below) is (are) installed and operational (this requirement supersedes the requirements of Item 5 of IE Bulletin 80-17 which required daily surveillance for only 6 days).
B.
Actions to bc Taken by BWR Licensees and Completed by September 1, 1980:
1)
Install a system to continuously monitor water levels in all scram discharge volumes. Continuous recording and alarm features must be
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included in the design. Consideration should be given to use of diverse level sensors in this (these) system (s). The design installed should represent the design with the highest level of reliability
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compatible with completion of installation by September 1, 1980.
Provide a written description of the system design to the NRC Regional Office.
e IE Bulletin No. 80-17 July 18, 1980 f-Supplement No. 1 Page 3 of 3 If installation by September 1, 1980 is not possible, by A'ugust 15, 1980, submit to the NRC Regional Office:
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1)
Documentation in detail why the installation cannot be completed by 9/1/80.
2)
A commitment to a firm schedule for installation.
3)
A commitment to equipment changes and/or surveillance requirements in addition to those now in effect that will provide adequate assurance of SDV operability in the interim until installation is completed.
2)
Perform a study of potential designs for improving the venting system for the scram discharge volumes and submit a description to NRC by September 1, 1980.
Improvements such as providing a redundant, independent vent for each significant volume in the system or locally installing vacuum breakers close te each such volume should be con-sidered (some plants already include a design which vents locally to atmosphere).
Include an estimate of the time that would be required to accomplish these modifications in your report to be submitted to the NRC Regional Office. We have been told that meetings have
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already been scheduled by GE to discuss their proposals in this area
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with licensees.
Additional requirements are under consideration and will be the subject of further communication from NRC.
Licensees of all operating BWRs shall submit the information requested within the specified allowable times.
This information is requested under the provis-ions of 10 CFR 50.54 (f). Accordingly, you are requested to provide within the time periods specified above, written statements of the above information signed under oadh or affirmation. Reports shall be submitted to the Director of the appropriate NRC Regional Office and a copy forwarded to the Director, Division of Reactor Operations Inspection, NRC. Office of Inspection and Enforcement, hbshington DC 20555.
Approved by GhD, B180225 (R0071); clearance expires 7-31-80.
Approval was given under.a llanket clearance specifically for identified generic prcblems.
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4 IE Bulletin No. 80-17 Enclosure
()SupplementNo.
1 July 18, 1980 RECENTLY ISSUED IE BULLETINS Bulletin Subject Date Issued Issued To No.
80-17 Failure Of Control Rods To 7/3/80 All BWR power reactor Supplement 1 Insert During A Scram At A facilities holding BWR OLs for ACTION and all BWR power reactor facilities holding CP for Info rmation.
80-17 Fadlure Of Control Rods To 7/3/80 All BWR power reactor Insert During A Scram At A facilities holding BMt OLs for ACTION and all BWR power reactor facilities holding CP for Information.
80-16 istential Misapplication of 6/27/80 All Power Reactor Easemount Inc., Models 1151 Facilities with an and 1152 Pressure Transmitters OL or a CP wjith Either "A" or "D" Output
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fades 80-15 Tessible Loss Of Hotline 6/18/80 All nuclear facilities h)di Loss Of Off-Site Power holding OLs 80-14 Jegradation of Scram 6/12/80 All BWR's with an JEscharge Volume Capability OL 80-13 Oncking In Core Spray 5/12/80 All BWR's with an Sprgers OL 80-12 Dezy Heat' Removal System 5/9/80 Each PWR with an OL Gprability 80-11 Huonry Wall Design 5/8/80 All power reactor facilities with an OL, except Trojan 80-10 16mtamination of 5/6/80 All power reactor 1beradioactive System and facilities with an Emulting Potential for OL or CP
.Ibanitored, Uncontrolled
..ficase to Environment 80-09
'fhdramotor Actuator-4/17/80 All power reactor
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.Ibiiciencies operating facilities and holders of power reactor
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construction permits
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