ML17213A840
| ML17213A840 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 08/12/1982 |
| From: | Leasburg R VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | Clark R, Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| 476, NUDOCS 8208170193 | |
| Download: ML17213A840 (4) | |
Text
REGULATO INFORMA'TION DISTRIBUTION,STEM ('R IDS)
F AOCESSION NBR:8208170193 DOC ~ DATE: 82/08/12 NOTARIZED:
NO
. 'OCKET FACIL:50-339 Nor th Anna.Power Stationi Unit 2i Vinginia Electr ic 8
05000339 AUTH,NAME AUTHOR AFFILIATION LEA'SBURGiR ~ H ~
Virginia El ectr ic 8 'Power Co ~
'RECIPeNAME RECIPIENT AFFILIATION DENTONiH ~ Ri Office of Nuclear Reactor Regulationi Director CLA'RKgR ~ AD Operating Reactors Branch 3
SUBJECT:
Provides suppl to evaluation of RCS Piping thermal
- sleeves, Util proposed al,ternative would be to detect damaged, or leaking '.thimble by incr easing testing to verify operability of incore detector leakage detection sys
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DISTRIBUTI N CODE:
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TITLE: General Distribution for after Issuance of.Operating License NOTES:
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VIRGINIALLECTBICAND POWER COMPANY RIGHXONDpVIRGINIA88~~61 R. H. LB~SIIauO VI08 PBBstDBBT NUGIBh II OPBBATI088 August 12, 1982 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation Attn:
Mr. Robert A. Clark, Chief Operating Reactors Branch No.
3 Division of Licensing U. S. Nuclear Regulatory Commission Washington, D. C.
20555 Serial No. 476 NO/JHL:acm Docket No. 50-339 License No. NPF-7 Gentlemen:
VIRGINIA ELECTRIC AND POWER COMPANY.
NORTH ANNA POWER STATION UNIT NO.
2 SUPPLEMENT TO THE EVALUATION OF RCS PIPING THERMAL SLEEVES By letter dated August 4,
1982 (Serial No.
460),
Vepco stated that incore instrumentation thimbles will be verified as operable by traversing the movable incore detectors in the lower vessel region on a weekly basis.
This would identify any potential damage or deformation of the instrument thimbles by a loose part in the vessel lower internals a'rea.
Vepco proposes an alternative to the above surveillance because the ability of a
movable incore detector to traverse a
thimble tube gives no definitive indication of the thimble's integrity. It is possible for a detector to pass through a damaged or deformed thimble. It is also possible for a detector to stick in an undamaged thimble due to lubrication or. incore drive mechanism problems.
The proposed alternative would be to detect a
damaged or leaking thimble by increasing testing to verify operability of the Incore Detector Leakage Detection System.
This system would give a
positive indication (control room alarm) of damage to an incore detector thimble.
The operability of the Incore Detector Leakage Detection System would be verified by performance of a functional test prior to Unit 2 startup and the alarm will be verified operable weekly by the Shift Technical Advisor to insure that any leakage would be immediately alarmed in the control room.
In addition, the normally required core surveillance which utilizes the incore movable detector system will be performed as scheduled.
These monthly flux maps will serve as further verification of the operability and integrity of the guide thimbles.
The Loose Parts Monitoring System will also identify any impact, vibration or movement of any loose parts in the vessel lower internals area.
cc:
Mr. James P. O'Reilly Regional Administrator Region II 8208170193 8208 i2 PDR ADOCK 05000339 p
PDR Very truly yours, L.z R. H. Leasburg If you have any questions, please contact us at your earliest convenience.
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