ML20040B103
| ML20040B103 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 12/31/1981 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20040B099 | List: |
| References | |
| NUDOCS 8201250153 | |
| Download: ML20040B103 (2) | |
Text
.
,,(# "%j, o, UNITED STATES y %g.r.,(g' j NUCLEAR REGULATORY COMMISSION g.
7/
WASHINGTON, D. C. 20555 a ?Mw/a f
/
j SAFETY EVALUATION SY THE OFFICE OF 'UCLEAR REACTOR REGULATION SUPPORTING AMENCMENT NO.35 AND NO.15 TO FACILITY OPERATING LICENSE N05. NPF 4 AND NPF-7 VIRGINIA ELECTRIC AND DOWER CCMPANY h0RTH ANNA POWER STATION, UtlITS NO. 1 AND NO. 2 DOCKET NOS. 50-338 AND 50-339
==
Introduction:==
By letter (Serial No. 491) dated September 21, 1981, the Virginia Electric and Power Company (the licensee) requested changes to the Technical Spec-ifications (TS) for the North Anna Power Station, Units No. 1 and 2 (NA-1
& 2). The requested changes would revise the. requirements for determining the Quadrant Pcwer Tilt Ratio (QPTR) when above 75% of rated thermal power with one Power Range Channel inoperable.
Discussion When one power range channel is inoperable, the QPTR must be monitored using the incore detectors.
The TS for NA-2 albw the QPTR monitoring to be per-formed with the four pairs of symmetric incore thimbles.
Since the four pairs (eight thimbles) are a subset of a full-core flux map (defined to have. greater than or ecual to 38 thimbles with a minimum of two per quadrant),the use of full-ccre map for nonitoring the NA-2 QPTR is acceptable.
Since the nuclear instrumentation configuration for NA-l&2 are identical, there should be no difference (which is not presently the case) in the pro-visions for using incore detectors to monitor the NA-1 QPTR when one power range channel is inoperable.
Therefore, the licensee has requested that the NA-1 TS be made identic31 to NA-2, and that the NA 1&2 TSs 4.2.4.2 explicitly state that a full-core map for monitoring she QPTR is acceptable.
Evaluation:
Our review of the licensee's requested change brought forth the fact that the present wording as stated in the Westinghouse Standard Technical Speci-fication (WSTS) (applicable to the NA-1&2 TS) was ambiguous.
Therefore we proposed a change to the WSTS 4.2.4 and NA1&2 TS 4.2.4 in cur discussions with Westinghouse and the licensee which reuds:
"The QUADRANT PCWER TILT RATIO shall be determined to be within the limit when above 75% of. RATED THERMAL POWER with one Power Range Channel inoperable by using the moveable incoce detectcrs to conf-irm that the ncrmalized sy: metric power distribution, obtained from 2' sets of 4 sy=etric thimble locations or a full-core flux map', is cons.isteht'with the. indicated QUACRANT PCWER TILT c '-
RAT!O at least cnce per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />."
The current WSTS and NA-1&2 TS reads, "..cbtained frcm the 4 pairs of symmetric thimble.locaticns...", and makes no mentien of 3 full core flux map as an alternative. Our proposed change as s::ecified above is also applicable to the NA-1&2 TS Table 3.3-h Action 2.d 8201250153 811231 PDR ADOCK 05000338 P
To eliminate any possibility of misunderstanding we also prcposed that a paragraph be added to the WSTS;and NA-l&2 TS. Bases, 4.2.4, which readsj__,
"ForpurposesofmonitoringQUADRANTPCWERTILTRhTIOwhenoneexcoredetector
~
is inoperable, the moveable incore detectors are used to confirm that the normalized symmetric pcwer distribution is consistent with the QUADRANT PCWER TILT RATIO.
The incore detectcr mcnitoring is done with a full incore flux map or two sets of 4 sytretric thimbles. The two sets of 4 symmetric thimbles is a unique set of 8 detector 1ccations.
These locations are C-8, E-5, E-il, H-3, H-13, L-5, L-ll, and.N-8."
This paragraph change is needed because the wording, "four pairs of symmetric thimbles" does not define a set of thimble locations useable for monitoring QPTR.
The specific set of 3 thimble locations is what Westinghcuse inteoded and is the se'. that should be used.
If one of these 8 locations is inoperable, a full incore flux map would give tha same results and therefore should be a viable option.
Therefore, based on the above, we find the licensee's proposed changes to the NA-l&2 TS to be acceptable. Also, our proposed changes, as discussed above, have been incorporated into the NA-l&2 TS.
Finally, the char.ges to.
the NA-l&2 TS are in conformance with the latest versions of the NRC approved WSTS.
Environmental Consideration We have determined that the amendments do not autho-i:e a change in effluent types or total amounts nor an increase in power level and will not result in any significant environmental impact.
Having made this determination, we have further concluded that the amendments involve an action which is insignificant from the standpoint of en vi ronren t al imoact and, pursuant to 10 CFR 551.5(d)(4), that an environmental impact statement or negative declaration and environ-mental imoact appraisal need not be prepared in connection with the issuance of these amendments.
Conclusion We have concluded, based on the considerations discussed above, that:
(1) because the amendments do not involve a significant increase
'a the probability or consequences of accidents previously considered and do not involve a significant decrease in a safety margin, the amendments do not involve a significant hazards consideration, (2) there is reasonable assurance that the healtn and safety of the public l
will not be endangered y operation in the proposed manner, and (3) p ;-
such activities will be conducted in compliance with the Commission's
_s regulations and the issuance of these amendments will not be inimical' eu,.
to the common defense and securi(y or to the-health and safety of the public.
Date: December 31, 1931 i
_ _ _ _ _