ML19325D792
| ML19325D792 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 10/05/1989 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML19325D791 | List: |
| References | |
| IEB-88-007, IEB-88-7, NUDOCS 8910260169 | |
| Download: ML19325D792 (4) | |
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NUCLEAR RROULATORY CONWisS60N i
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ENGLQiVRE 2 i
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR f(GULATION SUPPORTING 'AMENOMENT N0.174 TO FACILITY OPERATING L! RINSE N0. OPR-52 TENNESSEE VALLEY AUTHORITY SROWNS FERRY NUCLEAR PLANT. UNIT 2 I
DOCKET N0. 50-260 i
1.0 INTRODUCTION
i In a letter and enclosures from M. Ray. Tennessee Valley Authority (TVA), to i
the NRC dated June 20.1989 (Reference 1). TVA proposed Technical Specifica-I tions (TS) changes for Browns Ferry Nuclear Plant. Unit 2 (SPN2). The proposed-i changes define regions on the operating power-flow map and operating restric-tions on activities relating to these regions.
The proposed regions and restrictions are intended to avoid problems with i
theresi hydraul' c instability, which have been a focus of NRC attention fol-lowing the LaSalle instability event of March 1948. This attention has 3
lwsulted in the issuance of NRC Bulletin 88-07 and Supplement 1 to that bul-i etin (References 2 and 3). These provide NRC action requests for utilities to provide operator training, instrumentation verification and operatin cedures intended to minimize instability potential or consequences. g pro.
The requested operating procedures of Supplement 1 are based on the General i
flectric (GE) Interim Recomeendations for Stability Actions (!R$A).
They are i
presented in the attachment to the supplement.
These recommendations, along with other NRC staff requests presented in the supplement, constitute current NRC recosumendations for SWR thermal h draulic stability (THS) related opera.
i tions. They are the result of calcul tions and reviews by the NRC GE. the SWR Owners' Group and associated consultants. The bulletin supplement requested that licensees implement the IR$A (and other associated requests) by modifying
'3 relevant procedures. ' Modification of TS was not specifically requested since it is expected that long term solution implementation, to replace the interim i
recommendations, will begin within about a year. However, several Itcensees have modified their stab' lity TS to correspond to the bulletin requests. $1nce SFN2 currently has no stability related TS. TVA proposed TS addressing Supple-i ment I requests before restart of SFN2.
The proposed changes to the BFN2 TS are (1) addition of TS 3.5.M.1, 2 and 3 TS 4.5.M.1, Figure 3.5.M-1 and the addition of the associated Bases 3.5.M and (2) changes to TS 3.6.F.3 and 4.6 F.3, the addition of 3.6.F.4 and additions to the Bases for 3.6.F/4.6.F. There are also associated changes to the table of contents and list of illustrations.
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2.0 M M BI E The IRSA specify three rggions (A. B. C) on the power-flow asp involving different degrees of allowed or prohibited operation. Ti b sre bounded by constant flow lines or control rod lines lines of flow variation with all other reactor parameters. particularly con (trol rod position held constant).
Region A is above the 100 at 100 percent rated flow) percent rod line (intercepts 100 percent rated power and below 40 percent flow.
ten B is between the i
80 and 100 percent rod lines and below 40 percent flow.
ten C is above the 80 percent rod line and between 40 and 45 percent flow. De iberate entry into Regions A and 8 is not permitted, and if it occurs famediate exit is required.
For a Group 2 plant (such as SFN2) immediate scree is required in Region A.
while for region 8 control rod insertion or flow incrosse may be used to exit.
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1 Operations may be conducted in Region C. with suitable surveillance. if required during "startups" to prevent fuel damage.
If during operations in 0 or C instability occurs, the reactor shall be scrassed, with evideece for
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instability coming from Average Power Range Monitor (APM) escillation greater 2
than 10 alams. percent or Local Power Range Moniter (LPM) upscale or downscale j
The proposed SFN2 T5 conservatively impleastits these region designations and associated operational requirements by adding a new specification. TS 3/4.5.M.
Core Thoms1-Hydraulic stability, and power-flow map. Figure 3.5.M-1.
The regions designated in the figure are the same as in IRSA except that regions B an(ion!).C are combined inte a single Region !! (and Region A is designated i
Reg The IRSA operatin applied throughout Region !!.g restrictions of Reg' on 8 are conservatively i
i There is no allowed operation such as is l
pomitted by LRSA for, e.g., startup in Region C.
TS 3.5.M.1, 2 and 3 specify I
that operation is not pomitted in Regions I and !! and upon inadvertent entry, scram is required if in Region I, and insediate initiation of action to dooart by control rod insertion or flow increase is required for Region !!.
While exiting Region !!. scram is required if there are indications of Instability as evidenced by APRM oscillations above 10 percent peak-to-peak of I
rated power or LPRM esc 111ations above 30 percent, and PRM upscale or l
downscale alems require insediate checks of APM and LPRM readings. These requirements all meet or exceed the IRSA specifications and are acceptable T5 for meeting the bulletin roguests for implementing the interim recommendations.
TS 4.5.M provides serve 111ance requirements for determining that operation is l
t outside of Regtens I and !! when operating in the vicinity of these regions.
They toe are acceptable.
The new 8ases 3.5.M provides a reasonable discussion of the backgreend, regions, operations and requirements for these specifica-tions and is aise acceptable.
Bulletin 88-07. Supplement 1 also requested that plants which do not have effective l
automatic scram protection for regional oscillations (Group 2 plants in the IRSA). should initiate a manual reactor scram when two recirculation pumps trip l
(or "no pumps operating") with the reactor in the RUN mode.
SFN2 is a Group 2 plant, and the proposed addition of 3.6.F.4 to TS 3/4.6.F. Recirculation Pump i
Operation, is intended to comply with this request.
It specifies that the l
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reactor shall not be operated in the RUN mode with both recirculation pumps out-of-service, and an imediate manual scram is required. in the RUN mode.
following a trip of bell recirculation pumps. This is an acceptable implemen-t j
tation for tuo operation, and SFN2 75 de not peroit natended sing)le loop ver. $LO is permitted for a short time (24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> and it tien(SLO) a 14 therefore be noted that the Supplement 1 retirculatten pump trip scram l
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. request as stated in *(or "no operating'he licenses has sensitted to")* intends sc 1
the operating pump in SLO in t mode.
i modify the Bases for 3.6.F to address this issue prior to Unit 2 restart. The l
a staff finds this to be en acceptable approach.
There are aise modifications to T5 3/4.6.F.3 which currently permits operation for up to 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> with both recirculatten pumps eut-of-service. The modifica-tiens permit such operation at power only unfle not in the RUN mode. i.e.,
permitted only at low peuer. This is an acceptable change.
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i The overall conclusion of the review is that the proposed T5 changes and the l
material submitted te support the changes are acceptable.
It should be noted.
and others are continuing the review of THS. concerns.heuever, that th SE The SWROS is devolep i
several long term solutions for the problem.
It is expected that a selection i
will be announced by.the end of 1983. Any new frements resulting from the j
continuing generic review of THS concerns and long term solutions will be applicable to SF2 and may impact same of the operations, systems surveillance og TS found to be acceptable in this review.
- l We have reviewed the reports submitted by TVA for SFN2 proposing T$ changes i
relatinp to TMS requirements for power-flow map operating restraints and surveil ance. Based on this review, we have concluded that appro tation was submitted and the proper,ed penet-flow action regions, priate documen-surveillance and TS changes satisfy staff positions (NRC Sulletin 88-07 and Supplement 1).
and requirements in these areas. Operation in the modes proposed for SFNr is acceptable. This conclusion may be subject to future review based on results from the staff continuing generic review and conclusions on long teen solutions.
3.0 ENVIR0l# U TAL CONSIDERATION This amendment tweelves a change to a requirement with respect to the installa-tion er use of a facility component located within the restricted area as defined in 10 CFW part 20 and changes to surveillance requirements. The staff has degerurtned that the amendment involves no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that this amendment involves no significant hazards consideration and there has been no public comment on such f' nding. Accord-ingly, the amenht meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(g).
Pursuant to 10 CFR 51.22(b. no environmental impact statement nor environmental assessment need be prepare)d in connection wIth the issvance of the amenenent.
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4.0 fgylgg The Commission made a proposed determination that the amenement involves no significant hasards consideration which was published in the Fedoral Resister (54 FR 2M14) on July public comments Were r.12. 1989 and consulted with the State or nanoma, no eceived and the state of Alabama did not hav> any l
comments.
The staff has concluded, based on the considerations discussed above, that (1) there is reasonable assurance that the health and safet;r of the public will i
not be endangered by operation in the proposed manner, and it) such activities i
will be conducted in compliance with the Cannission's regulations, and the issuance of the amendments will not be inimical to the common defense and security nor to the health and safety of the public.
5.0 KFERIEE5
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i 1.
Letter from M. Ray, TVA, to NRC. dated June 20,1989. ' Browns Ferry Nuclear Plant (SFN) - TVA SFN Technical Specification No. 272 -
Thermal-Hydraulic Stability Section 3.5/4.5-M."
2.
NRC Sulletin No. 88 07: Power Oscillations in Boiling Water Reactors (SWR) dated June 15. 1988.
3.
.NRC Sulletin No. 88 0). Supp1mment 1: Power Oscil!ations in Boiling Water l
. Reactors (BWR).' dated December 30, 1988.
Principal Contributor:
H. Rich ugs Dated:
October 5, 1989 1
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