ML18024A940
| ML18024A940 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 08/06/1979 |
| From: | Mills L TENNESSEE VALLEY AUTHORITY |
| To: | Ippolito T Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 7908100487 | |
| Download: ML18024A940 (14) | |
Text
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Tennessee Yalley Authority REclp.uArrE REclpIE'r T ~FFILIATIov IPPOL I TO P T ~ A ~
Operating Reactors Branch 3
SUBJECT:
Responds to 79072V ltr 8 forwards addi response to IE Bulletin 79-08 re initiation of containment isolation, DISTRIBUTION CODE:
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TENNESSEE VALLEYAUTHORITY CHATTANOOGA. TENNESSEE 37401 400 Chestnut Street Tower II August 6, 1979 Director of Nuclear Reactor Regulation P))f g~
Attention:
Mr. Thomas A. Ippolito, Chief Branch No.
3 Division of Operating Reactors U.S. Nuclear Regulatory Commission washington, DC 20555
Dear Mr. Ippolito:
In the Matter of the Tennessee Valley Authority Docket Nos.
50-259 50-260 50-296 This is in response to your letter of July 20, 1979, to H. G. Parris.
Enclosed is the additional information you requested concerning the TVA response to IE Bulletin 79-08 for Browns Ferry Nuclear Plant.
Very truly yours, TENNESSEE VALLEY AUTHORITY
. M. Mills, nager Nuclear Regulation and Safety Enclosure 908y0o98 I
An Equal Opportunity Employer
BROGANS PERRY 1, 2, AND 3 RE UESTS FOR ADDITXONALINFOKlATION IEB 79-08 Xtem No.
2 1.
Verify that your review considered initiation of containment isola-tion of all lines penetrating containment (including those designed to transfer potentially radioactive gases and liquids out of contain-ment) upon all automatic initiations of safety injection.
2.
Provide a schedule for implementation of any changes that may be required and describe how they meet the requirements of the Bulletin.
Res onse to Xtem No.
2 1.
Our review considered initiation of containment isolation of all lines penetrating containment (including those designed to transfer potentially radioactive gases and liquids out of containment) on receipt of a primary containment isolation signal (PCIS).
The PCXS setpoints are chosen so that isolation will occur before or at the same time that ECCS initiates.
2.
No changes are necessary to meet the requirements of the Bulletin.
Item No.
4 1.
Clarify your response to indicate whether operators have been instructed to utilize other available information to initiate safety systems.
provide your schedule for completion of this action.
Res onse to Item No.
4 1.
Operators have been instructed to utilize other available informa-tion to initiate safety systems.
This training has been completed.
0
Item No.
5 l.
It is not clear from your response whether your re'view with respect to the action directed by item 5b included all operating procedures and training instructions.
Amend your responses to clarify this point.
2.
Provide a schedule forany actions on item 5 that have not, yet been completed.
Res onse to Item 'No.
5 l.
All operating instructions and training instructions have been reviewed and.revised as necessary to instruct operators not to rely on vessel level indication alone for manual actions, but, to also examine other plant parameter indications in evaluating plant conditions.
2.
All actions have been completed.
Item No.
6 It is not clear from your response that safety related valve positioning requirements were reviewed to ensure proper operation of engineered safety features.
Please supplement your response to
'rovide a commitment to conduct this review and a schedule for completion.
2.
Please augment your response to indicate the extent to which position and locking device checks are performed for locked safety system valves.
3.
Your response did not clearly indicate that all accessible safety related valves had been inspected to verify proper position.
Nor was a schedule for, performing the position verification for all safety related valves provided.
Please supplement your response to provide this information.
Res nse to Item No.
6 2 ~
Safety related valve position requirements have been reviewed to ensure proper operation of engineered safety features;.
This review has been completed.
CSSC valve position requirements are listed and documented in the operating instruction valve checklist for each individual system.
r The complete system valve checklist is done before startup following each re'fueling outage and placed in the system status files.
Locked safety system valves are included on the checklists.
If the position of any locked valve is required to be changed, an "abnormal status" form is filled out and placed in the status file foz the appropriate system.
The form states the normal and abnormal.
condition and the reason for the abnormal status.
Should this change render the system or component inoperable, further action
is directed as outlined in Xtem No.
8 of this letter.
When the locked valve is returned to the normal position, the abnormal status sheet is removed from the file.
The file is reviewed for completeness and abnormal status by a weekly status review procedure.
Hajor flow path valves for each system are checked on a separate panel checklist for proper position weekly.
Accessible safety related valves in the main flow path of CSSC equipment have been inspected to verify proper positioning.
This verification is performed by a weekly status review procedure.
Item No.
7 l.
Your response does not explicitly address the actions of isolation valves on resetting safety features instrumentation.
Provide assurance that inadvertent transfer of radioactive gases and liquids out of containment will not occur on resetting safety features instrumentation.
2.
Discuss the basis upon which continued operability is assured for those features designed to prevent inadvertent transfer of radio-active liquids and gases.
Res onse to Item No.
7 l.
We have reviewed the opera'ting modes and procedures designed to transfer potentially radioactive liquids and gases from the primary containment.
We have concluded that the likelihood of inadvertent transfer of.highly radioactive material is very low.
Li uid S stems The drywell drain sump and drywell equipment drain sumps will isolate on receipt of a PCIS signal.
The PCIS is generated by low reactor water level or high drywell pressure.
If reactor level can be restored and the drywell pressure reduced below 2 psig, the PCIS signal may be manually reset and automatic operation of these sump valves and pumps is not prohibited.
- However, we have not identified conditions that would involve a significant breach of the primary system and at the same time not initiate and maintain a PCIS signal.
The subject pumps are low capacity (50 gpm) and control room annuncia-tors will alarm if either pump operates an excessive time (about 10 minutes).
The unit'operator or radwaste operator can remotely secure the system if high radiation is suspected as indicated by monitors in the containment and radwaste areas.
Item No.
8 We understand from your response that operability is verified for redundant safety related systems prior to removal of any safety related system from service.
Since you may be relying,.
on prior operability verification within the current technical specification surveillance interval, operability should be further verified by at least a visual check of the system status to the extent practicable, prior to removing the redundant equipment from service.
Please supplement your response to provide a commitment that you will revise your maintenance and test procedures to adopt this position.
2 ~
It is not clear from your response that all involved reactor operational personnel in the oncoming shift are explicitly notified'bout'the status of systems removed from or returned to service.
Please indicate how this information is transferred at shift turnover.
Res nse to Item No.
8 Prior operability verification within the current technical specification surveillance interval is not relyed on.
Plant specific administrative procedures, based on technical specifica-tions, require that'edundant safety system(s) be proved operable by performance of applicable surveillance instruction(s) before removing a safety system from service.
The above position is reflected in plant maintenance and test procedures and exceeds the proposed requirement to perform a visual check of system status.
2.
Plant procedures require that systems removed from or returned to service be documented in the operator's daily journal and
.that each oncoming o'perator read the journal back to the last shift worked or 5 calendar
- days, whichever is less.
Although the likelihood of inadvertent transfer of highly radioactive material is low, TVA intends to install detectors on these sump lines to interlock sump system operation when high radiation is present in the sump line effluent.
In the meantime, plant operating instructions require that, before resetting a,PCIS signal, an evaluation be made to ensure that inadvertent transfer of significant amounts of contaminated fluids will not occur.'entilation S stems The primary containment ventilation valves will automatically isolate (if open) on receipt of the PCIS signal.
Furthermore, these valves cannot be reopened if high radiation exists in the reactor building ventilation ducts.
2.
Browns Ferry technical specifications require periodic surveillance testing of the PCIS logic and primary containment sump and ventilation valves.