ML19332B071

Forwards Response to IE Bulletin 80-14 Re Degradation of BWR Scram Discharge Vol Capability.No Instances of Level Switches or Vent & Drain Valve Failure Identified.Bulletin Required 10 Manhours

ML19332B071
Person / Time
Site:	Vermont Yankee File:NorthStar Vermont Yankee icon.png
Issue date:	07/28/1980
From:	Tribble J VERMONT YANKEE NUCLEAR POWER CORP.
To:	Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
IEB-80-14, WVY-80-108, NUDOCS 8009190947
Download: ML19332B071 (3)

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c 7ERMONT YAN KEE NUCLEAR POWER CORPORATION d SEVENTY SEVEN GROVE STREET B.4.1.1 RuTLAxo, VERMONT 05701 WVT 80-108 REPLY tot J'uly 28, 1980 ENGINEERING OFFICE TURNPIKE RO AD WESTBORO M ASS ACHUSETTS 01581 United States Nuclear Regulatory Commission Office of Inspection and Enforcement Region I 631 Park Avenue King of Prussia, Pennsylvania 19406 Attention: Mr. Boyce H. Grier, Director

References:

(a) License No. DPR-28 (Docket No. 50-271)

(b) USNRC Letter to VYNPC dated June 12, 1980 IE Bulletin No. 80-14

Enclosure:

(a) Response to IE Bulletin No. 80-14

Subject:

Response to IE Bulletin No. 80-14, " Degradation of BWR Scram Discharge Volume Capability"

Dear Sir:

This letter is written in response to Reference (b) which requested Vermont Yankee to perform specific reviews and take certain actions concerning Scram Discharge Volume Degradation. Enclosure (a) addresses each item specified.

The following information is submit.ted in response to your request for an estimate of the manpower expended in the -research and response for this Bulletin:

Manpower Act,ivity Manhours Expended Research and response preparation 10 Corrective Actions 0 Please note that a significantly higher amount of manhours is also being expended in investigating the scram discharge system in accordance with IE Bulletin 80-17.

We trust that this information is satisfactory; however, should you desire additional information, please contact us.

l Very truly yours ,

VERMONT YANKEE NUCLEAR POWER CORPORATION gg g ry

/

J. E. Tribble Vice President JRW/ dis

F

. ENCLOSURE A RESPONSE TO IE BULLETIN NO. 80-14

1. Review plant records for instances of degradation of any SDV level switch which was or may have been caused by a damaged or bent float assembly.

Identify the cause and corrective action for each instance.

Response: Plant surveillance records and Licensee Event Reports have been reviewed and no instances of failed SDV level switches due in any part to the float assembly were found.

2. Review plant records for instances of degradation of SDV vent and drain valve operability. Provide the closure times required and typically observed for these valves and the basis for the required closing times.

Identify the cause and corrective action for each instance of degradation.

1 Response: Plant surveillance records and Licensee Event Reports have been reviewed and no instances of failed SDV vent and drain valves were found. Typical opening and closing times from recent tests are indicated beltw:

Test Signal Manual Scram Signal Open to close (sec) Close to open (sec) Open to close (sec)

Drain 4.8 6.8 2.7 Vent A 7.8 3.9 9.1 Vent B 4.3 10.4 4.9 We feel that the acceptability of operating times and the operability of the entire scram discharge system is more properly addressed in our response to IE Bulletin 80-17, Supplement 1, which is currently in preparation.

3. By procedures, require that the SDV vent and drain valves be normally operable, open and periodically tested. If these valves are not operable or are closed for more than I hour in any 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> period during ,

operation, the reason shall be logged and the NRC notified within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> (Prompt Notification) .

Response: SDV Vent and drain valve positions are currently logged once per shif t and are periodically operationally tested. The required notification program has been included in plant procedures . The requirement to log plant equipment in and out of service is contained in plant procedures.

4. Review instances in which water hammer or damage which may have been caused by water hammer has occurred in SDV related piping. Identify the cause and corrective action for each instance.

Response: Vermont Yankee has never experienced any failures of the scram discharge volume system which would indicate that it had been subjected to water hammer. In response to this b j

Enclosure A Response to IE Bulletin No. 80-14 Page 2 i

i

) . Bulletin; we have completely visually inspected all the major supports of this system for looseness or binding with no degradation j observed.

5. Review surveillance procedure to ensure that degradation of any' SDV level switch due to a damaged fl' oat or other cause would be detected and that 1 inoperability from any cause would be reported to the NRC.

Response: Vermont Yankee has reviewed its surveillance procedures and has determined that they are capable of detecting the type of failures described by this Bulletin. The requirements for notification of the NRC have been included in plant procedures.

6.

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If no functional test or inspection which would detect degradation of

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each SDV level switch has been performed during the past 3 months, make provisions to perform an inspection and functional test of all SDV level a

switch assemblies at the next reactor shutdown of greater than 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> duration.

. Response: SDV level switches are functietally tested every three months I and there have been no instr ac ts found of degradation of the float assemblies. The only failure in this system that Vermont Yankee has experienced was reported to the NRC in RO 74-15 as a faulty mercury switch. No specific testing is necessary to i comply with this Bulletin. Please note that a significant amount of testing in this area is required by IE Bulletin 80-17.

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