ML19338C253
| ML19338C253 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 07/28/1980 |
| From: | Mills L TENNESSEE VALLEY AUTHORITY |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| IEB-80-14, NUDOCS 8008140283 | |
| Download: ML19338C253 (5) | |
Text
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TENNESSEE VALLEY AUTHORITY
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400 Chestnut Street Tower II ra :n r.!i : 35 July 28, 1980 Mr. James P. O'Reilly, Director Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Region II - Suite 3100 101 Marietta Street Atlanta, Georgia 30303
Dear Mr. O'Reilly:
OFFICE OF INSPECTION AND ENFORCEMENT BULLETIN 80 RII:JPO 50-259, -260, -296 - BROWNS FERRY NUCLEAR PLANT In response to your June 12, 1980, letter which transmitted OIE Bulletin 80-14, enclosed are the results of our investigations for the Browns Ferry Nuclear Plant. Also, as requested by the subject bulletin, in order to assist the NRC in evaluating the value/ impact of each bulletin, provided with the enclosure is an estimate of the manpower expended in the conduct of the review and preparation of this report. If you have any questions regarding the subject. bulletin, please call Jim Domer at F2S 857-2014.
Very truly yours, TENNESSEE VALLEY AUTHORITY k.ils M Nuclear Regulation and Safety Enclosure cc:
U.S. Nuclear Regulatory Commission (Enclosure)
Office of Inspection and Enforcement Division of Reactor Operations Washington, DC 20555 800814 0 2 E 3 poyer An Equal Opportunity Em YWT " #-
ENCLOSURE RESPONSE TO NRC OIE BULLETIN 80-14 DATED JUNE 12, 1980 BROWNS FERRY NUCLEAR PLANT The results of our investigations for the Browns Ferry uclear Plant are given below. Each item for the bulletin is addressed as listed in the bulletin. Also, as requested by the subject bulletin, an estimated, of the manpower expended in the conduct of the review and in preparation of this report is provided.
Item A.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
There have been two instances where the ball float on the SDV high-level alarm has been penctured.
The cause of the damage was not determined.
The corrective action in each case was replacement of the damaged float.
Item A.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 bcsis for the required closing times.
Identify the cause and corrective action for each instance of degradation.
Response
There has been one instance of degradation of SDV vent and drain valve operability.
In this incident, both vent valves on Browns Ferry Nuclear Plant unit 3 would not close.
The cause of the failure to close was misadjustment of the valve stem couplings.
The corrective action was,
adjustment of the valve stem couplings.
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Based upon information supplied by General Electric Company, the specified stroke time for the scram discharge volume vent and drain valves is 1 30 seconds following a scram.
Closure times observed during Browns s
Ferry unit 3 testing in accordance with IE Bulletin 80-17 were 16 seconds or less. The only purpose for these valves is to limit the quantity of reactor water discharged after a scram, i.e., these valves have no safety functions.
If the reactor is left in a scram condition, reactor water will continue to leak past CRD seals indefinitely.
Leakage does not begin until after the scram stroke is complete; therefore, there is no need for fast closure of these valves.
Specifying a stroke time of 1 30 seconds allows the purchase of readily available valves of known reliability.
Item A.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 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> in any 24-hour 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
Present plant operating instructions require that the SDV vent and drain valves be normally open and operable. Surveillance instructions have been revised tc incorporate periodic testing of these valves. The CRD system operating instructions have been revised to include the prompt notification requirement.
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Item A.4 Review instances in which water manner 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
No instances of water hammer or damage which may have be'en caused by water hammer have occurred.
Item A.5 Review surveillance procedures to ensure that degradation of any SDV level switch due to a damaged float or other cause would be detected and that inoperability from any cause would be reported to the NRC.
Response
At the issuance of the Bulletin, only the SDV high-level scram switches
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were functionally checked and calibrated by surveillance instructions, with t option in the instruction to functionally check the high-level alarm switch. Appropriate surveillance instructions have been modified to ensure that the high-level alarm and rod block switches are also periodically functionally tested and calibrated.
Inoperability reporting for these switches is not presently in the plant technical specifications and was included in the appropriate instruction.
Item A.6 If no functional test or inspection which would detect degradation of each SDV level switch has been performed during the past three months,
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make provisions to perform an inspection and functional test of all SDV level switch assemblies at the next reactor shutdown of greater than 48-hours duration.
Response
As stated in the response to Item A.5, all high-level scram switches are functionally tested and calibrated on a periodic basis and all other level switches have been added to the surveillance program.
Appropriate calibrations and functional testing will be performed either at the next reactor shutdown greater than 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> or before.
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-4 Manpower Required for Corrective Action /Reporti ng Approximately 80 man-hours were expended in revi Response to the bulletin.
ewing and preparing the Approximately 40 man-hours were expended in making the necessary changes described above e
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