ML17289B156
| ML17289B156 | |
| Person / Time | |
|---|---|
| Site: | Columbia  |
| Issue date: | 02/10/1993 |
| From: | Sorensen G WASHINGTON PUBLIC POWER SUPPLY SYSTEM |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML17289B157 | List: |
| References | |
| GO2-93-029, GO2-93-29, NUDOCS 9302170334 | |
| Download: ML17289B156 (9) | |
Text
ACCEI ERA~9 DOCUMENT DIST BVTION SYSTEM REGULARLY INFORMATION DISTRIBUTI SYSTEM (RIDS)
A ACCESS)ON'NBR:9302170334 DOC.DATE: 93/02/10 NOTARIZED: YES DOCKET FACIL:50-397 WPPSS Nuclear Project, Unit 2, Washington Public Powe 05000397 AUTH. NAME AUTHOR AFFILIATION SORENSEN,G.C. Washington Public Power Supply System RECIP.NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)
SUBJECT:
Application for amend to License NPF-21,changing TS 4.1.3.1.4.a, "Reactivity Control Sys,Scram Discharge Vol Valve Testing" from normal control rod configuration to allow test to be conducted under shutdown conditions.
DISTRIBUTION CODE: AOOIS TITLE: OR COPIES RECEIVED:LTR Submittal: General Distribution Z ENCL 4 SIZE: g~ I NOTES:
RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD5 LA 1 1 PD5 PD 1 1 CLIFFORDgJ 2 2 INTERNAL: ACRS 6 6 NRR/DET/ESGB 1 1 NRR/DOEA/OTSB11 1 1 NRR/DST/SELB 7E 1 1 NRR/DST/SICB8H7 1 1 NRR/DST/SRXB 8E 1 1 NUDOCS-ABSTRACT 1 1 C. B 1 0 OGC/HDS1 1 0 REG FIL 01 1 1 EXTERNAL: NRC PDR 1 1 NSIC 1 1 NOTE TO ALL"RIDS" RECIPIENTS:
PLEASE HELP US TO REDUCE WASTEl CONTACT THE DOCUMENT CONTROL DESK, ROOM Pl-3'1 (EXT. 504-2065) TO ELIMINATEYOUR NAME FROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEEDI TOTAL NUMBER OF COPIES REQUIRED: LTTR 21 ENCL 19
WASHINGTON PUBLIC POWER SUPPLY SYSTEM P.O. Bort968 ~ 3000 George Wasbtngton Way ~ Rtcbland, Wasbtngton 99352-0968 ~ C5093372-5000 February 10, 1993 G02-93-029 Docket No. 50-397 U.S. Nuclear Regulatory Commission Attn; Document Control Desk Washington, D.C. 20555 Gentlemen:
Subject:
WNP-2, OPERATING LICENSE NPF-21 REQUEST FOR AMENDMENTTO TECHNICAL SPECIFICATION 4.1.3.1.4.a, REACTIVITYCONTROL SYSTEMS, SCRAM DISCHARGE VOLUME VALVETESTING In accordance with the Code of Federal Regulations, Title 10 Parts 50.90 and 2.101, the Supply System hereby submits a request for amendment to the WNP-2 Technical Specifications. This proposal requests that the requirement to test the scram discharge volume (SDV) vent and drain valves from a normal control rod configuration of less than or equal to 50% ROD DENSITY be changed, as attached, to allow the test to be conducted under shutdown conditions.
The SDV consists of two header piping volumes and two instrument volumes. Each header volume is sized to receive and contain the water discharged by approximately one half of the control rod drives during a scram, independent of the instrument volumes. Vent lines from each header volume are joined in a common vent line and vented by two valves in series. The drain lines of each instrument volume are combined in a common drain and controlled by two drain valves also in series. The SDV vent and drain valves are normally open and discharge any accumulated water in the SDV to ensure sufficient volume is available at all times to allow a complete scram. When a scram occurs, the SDV vent and drain valves close to contain reactor water. Redundant in series valves are used to ensure that no single failure can result in an inability to isolate. Closure, as specified by the Technical Specifications, within 30 seconds ensures reactor coolant containment.
ggoo l J 9302i70334 9302f0 PDR ADOCK 05000397 P PDR
"'Qg' T'age 2 REQUEST FOR AMENDMENTTO TS 4.1.3.1.4.a
'DV VALVETESTING When the scram signal is cleared from the Reactor Protection System, a scram reset command from the operator opens the SDV vent and drain valves, the volume is drained and returned to atmospheric pressure. The surveillance also proves the operability of the valves to return to open upon scram signal reset, As presently required the surveillance must be conducted at power with a normal control rod configuration of less than or equal to 50% rod density. However, operability can be satisfactorily confirmed under shutdown conditions when the proof of operability also considers normal operating events and other required surveillances. Reactor pressure and control rod drive discharge flow conditions, at power in comparison to shutdown, do not significantly influence the SDV vent and drain valve closure rates because the SDV is of sufficient volume and initially vented such that peak pressure prior to SDV isolation, valve closure, will not be substantial, At less than or equal to 50% control rod density, backpressure would become significant following a test, but would not be significant during the closing stroke of the valves. However, Surveillance 4.1.3.1.1 performs an operability verification of the valves at least once per 92 days by cycling each valve through at least one complete cycle of travel. The lower coolant temperatures expected during testing at shutdown conditions will also have a negligible impact on the performance of the surveillance. Hence, because the parameters of a test under shutdown conditions are not significantly different from those encountered during a test at power and valve operability is also confirmed quarterly (Technical Specification Surveillance 4.1.3.1. 1) there is no significant benefit gained by performance of the test at less than or equal to 50% rod density.
Allowing the test to be performed under shutdown conditions also proves operability of the valves prior to moving into the applicable operational condition for which operability is required.
Consequently, the note at the bottom of page 3/4 1-5 allowing a waiver of Specification 4.0.4 can be deleted with approval of this change.
Further benefit for testing under shutdown conditions is realized in that the shutdown test represents a plant transient of lesser magnitude than the test at power. Decreasing the magnitude and number of plant transients is an obvious benefit to the plant, the equipment being exercised and to those presently required to conduct the test at a more critical plant condition.
The Supply System has evaluated this change per 10 CFR 50.92 and determined that it does not represent a significant hazards consideration because it does not:
r 'a d ~
p C
'Page 3 REQUEST FOR AMENDMENTTO TS 4.1.3.1.4.a
~
SDV VALVETESTING
- 1) Involve a significant increase in the probability or consequences of an accident previously evaluated. No significant increase in the probability or consequences of an accident previously evaluated is represented by this change since the OPERABILITYof the SDV vent and drain valves can be adequately demonstrated during a scram from shutdown conditions. The conditions under which the test will be performed, shutdown, are not the same as those when tested at less than or equal to 50% ROD DENSITY, however the difference in the conditions does not significantly impact the performance of the SDV vent and drain valves. The inoperability of the SDV vent and drain valve system is not an accident precursor for a design basis transient or accident analysis. For these reasons, this change will not increase the probability of an accident previously evaluated.
Additionally, the consequences of an accident are not increased. The ability to isolate the reactor coolant after an event is unchanged. Plant procedures (controlled by 10 CFR 50.59) establish the conditions under which the surveillance is performed. As such, adequate controls exist to ensure any changes to the conditions of the test do not increase the probability or consequences of previously evaluated accidents.
- 2) Create the possibility of a new or different kind of accident from any accident previously evaluated because the proposed change introduces no new mode of plant operation nor does it require physical modification to the plant.
- 3) Involve a significant reduction in a margin of safety. No reduction in a margin of safety is involved with this change since the OPERABILITY of the SDV vent and drain valves can be adequately demonstrated under shutdown conditions. Additionally, the change allows the SDV vent and drain valves to now be demonstrated OPERABLE prior to entering the applicable mode for which OPERABILITY is a requirement. The change also represents a benefit to the plant and staff in that it decreases the magnitude of a required plant evolution by allowing the testing to be done at a less critical plant condition. Accordingly, the change to allow the test to be conducted under shutdown conditions does not involve a significant reduction in a margin of safety.
As discussed above, the Supply System has concluded that this change does not involve a significant hazards consideration, nor is there a potential for a significant change in the types or significant increase in the amount of any effluents that may be released offsite, nor does the change involve a significant increase in individual or cumulative occupational radiation exposure.
Accordingly, the proposed change meets the eligibilitycriteria for categorical exclusion set forth in 10 CFR 51.22(C)(9) and therefore, per 10 CFR 51.22(b), an environmental assessment of this change is not required,
1 s
'Page 4 REQUEST FOR AMENDMENTTO TS 4.1.3.1.4.a
'DV VALVETESTING This Technical Specification change request has been reviewed and approved by the WNP-2 Plant Operations Committee and the Supply System Corporate Nuclear Safety Review Board.
In accordance with 10 CFR 50.91, the State of Washington has been provided a copy of this letter.
Sincerely, G. C. Sorensen, Manager Regulatory Programs (Mail Drop 280)
PLP/b16 Attachments CC: W Bishop - EFSEC JB Martin - NRC RV NS Reynolds - Winston & Strawn JW Clifford - NRC DL Williams - BPA/399 NRC Site Inspector - 901A
STATE OF WASHINGTON )
Subject:
Req. for Amend. to TS 4.1.3.1.4.a
) Reactivi ntr 1 s DV Valve T in COUNTY OF BENTON )
I. G. C. SORENSEN, being duly sworn, subscribe to and say that I am the Manager, Regulatory Programs for the WASHINGTON PUBLIC POWER SUPPLY SYSTEM, the applicant herein; that I have the full authority to execute this oath; that I have reviewed the foregoing; and that to the best of my knowledge, information, and belief the statements made in it are true.
DATE >> +C , 1993 G. C. So sen, Manager Regulatory Programs On this date personally appeared before me G. C. SORENSEN, to me known to be the individual who executed the foregoing instrument, and acknowledged that he signed the same as his free act and deed for the uses and purposes herein mentioned.
GIVEN under my hand and seal this ~/day of 1993.
Ay Notary Public in and for the STATE OF WASHINGTON Residing at Kennewick Washin ton My 8 8 4 Ii*84 ~A'128 2 4