ML20247L849
| ML20247L849 | |
| Person / Time | |
|---|---|
| Site: | Brunswick  |
| Issue date: | 05/25/1989 |
| From: | Adensam E Office of Nuclear Reactor Regulation |
| To: | Eury L CAROLINA POWER & LIGHT CO. |
| References | |
| 2.206, NUDOCS 8906020275 | |
| Download: ML20247L849 (2) | |
Text
E) s May 250 1989 Docket Nos. 50-325 DISTRIBUTION
> 50-324 See next page f
e Mr. Lynn W. Eury Executive Vice President Power Supply ;
Carolina Power & Light Company '
Post Office Box 1551 Raleigh, North Carolina 27602
Dear Mr. Eury:
SUBJECT:
DIRECTOR'S DECISION IN RESPONSE TO 2.206 PETITION REGARDING BWR STABILITY Enclosed for your information are copies of a Director's Decision, letter of transmittal and Federal Register notice issued by the Director, Office of Nuclear Reactor Regulation (Director) in response to a Petition filed under 10 CFR 2.206 of.the Commission's regulations. The Petition was filed by Ms. Susan Hiatt on behalf of the Ohio Citizens for Responsible Energy (OCRE). :
The Petitioner expressed concerns regarding the March 9,1988 power oscillation (
event at LaSalle, Unit 2 and requested that the Director and Commission take >
specified action with. respect to all boiling water reactors. As discussed in the enclosed Director's Decision, the Petitioner's request under 10 CFR 2.206 has been denied. However, the Petitioner's request to reopen rulemaking l proceedings regarding Anticipated Transients Without Scram (ATWS) is being treated as a petition for rulemaking under 10 CFR 2.802 of the Commission's regulations.
Please contact me at (301) 492-14.66 if you have any questions on this issue.
Sincerely, ;
Original Signed By: l Elinor G. Adensam, Director ;
Project Directorate 11-1 '
Division of Reactor Projects -I/II Office of Nuclear Reactor Regulation l
Enclosures:
- 1. Letter dated April 27, 1989 to Ms. Susan L. Hiatt i
- 2. Director's Decision dated April 27, 1989
- 3. Federal Register Notice dated Apri.I 27, 1989 cc w/ enclosures:
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- ,- ENCLOSURE 1 i.*ess,
- - + 5 UNITED STATES
! ,- NUCLEAR REGULATORY COMMISSION
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\.'..../ April 27, 1989 DD-89-03 l
Ms. Susan I.. Hiatt Representative of Ohio Citizens for 3 Responsible Enercy, Inc.
8275 Munson Road Mentor, Ohio 44C60 j
Dear Ms. Hiatt:
This letter is in further response to your Petition of July 22,1988 requesting that the Director, 0ffice of Nuclear Reactor Regulation (NRR), take Ismediate action with respect to boiling water reactors (BWRs) to relieve what you allege to be undue risks to the public health and safety posed by the thermal-hydraulic instability of BWRs as revealed by an event at LaSalle County Station Unit 2, on March g,1988.
On August 26, 1968, I informed you that your request for immediate relief was denied because the allegations that form the basis for your Petition did not reveal any new operational safety issue that posed an ismediate safety concern for continued BWR operation. I also informed you that your Petition was being treated under 10 CFR 2.206 of the Comnission's regulations and that appropriate a action, that is, a formal decision, would be taken within a reasonable time.
For the reasons set forth in the enclosed Director's Decision under 10 CFR 2.206, your Petition has been denied. However, as discussed below, your request to ,
reopen rulemaking proceedings regarding anticipated transients without scram f
'(ATWS) is being treated as a Petition for rulemaking under 10 CFR 2.802 of the
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Consnission's regulations. A copy of the Decision will be filed with the Secretary of the Connission for the Cosmission's review in accordance with 10 CFR 2.206.
The Decision will constitute final action of the Cosmission 25 days after the cate of issuance unless the Connission, on its own motion, institutes a review of the Decision within that time.
In the August 26, 1988 letter, I acknowledged your request to reopen rulemaking proceedings regarding ATUS as part of the relief requested. However, since that '
time, I have determined that this request is more properly treated as a petition .
for rulemaking under 10 CFR 2.802 of the Cosmission's regulations. As such, it has been referred to the NRC Office of Research for appropriate action. However. I
, it is important to note thtt both the NRC and BWR Owners Group (BWR06) currently have programs in which analyses of ATWS conditions are being conducted. These analyses treat large amplitude power oscillations with state-of-the art analytical methods. The results of these analyses to date confire the technical bases for the current ATES rule. Consequently, at this time, the NRC staff sees no basis for recoronending that the Cosmissien reopen rulemaking proceedings regarding ATWS. i If, however, the staff finds evidence which contradicts the assumptions and results i of previous ATW5 analyses from either the information you provided in support of thenyour bePetition or new appropriate for information fromtoongoing the Conrission NRC reconsider and the BWR06 current programs,le.it A"WS ru may h
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Susan L. Hiatt i For your information, I am enclosing a copy of Supplement I to NRC Bulletin he. SS-07, " Power Oscillations in Boiling Water Reactors", which is referenced in the Director's Decision. I am also enclosing a copy of the notice regarding this Decisior, that was filed with the Office of the Federal Register for publication.
Sincerely, E
Thomas E. Murley, Director Office of Nuclear Reactor Regulation
Enclosures:
- 1. Directer's Decision
- 2. Federal Recister hotice
- 3. NRC bulletin ho. 88-07, Supplement 1 E
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... ENCLOSURE 2
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00-89-03 l
UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION OFFICE OF NUCLEAR REACTOR REGULATION Thomas E. Murley,' Director In the Matter of BOSTON EDISON CO. (Pilgrim Nuclear Power Station, Docket No. 50-293)
, CAROLINA POWER & LIGHT CO. (Brunswick Station, Units I and 2 Docket Mos. 50-324 and 50-325)
CLEVELAND ELECTRIC ILLUMINATING CO., ET AL. (Perry Nuclear Power Plant, Unit 1, '
Docket No. 50-440)
COMMONWEALTH EDISON CD. (Dresden Nuclear Power Plant, Units 2 and 3 Docket hos. #
50-237 and 50-249), (Quad Cities Nuclear Power Plant, Units 1 and 2, Docket Nos.
. 50-254 and 50-265), (LaSalle County Station, Units 1 and 2, Docket Nos. 50-373 and 50-374)
CONSUMERS POWER CO. (Big Rock Point, Docket No. 50-155)
DETROIT EDISON CO. (Fermi Unit 2. Docket No. 50-342)
GENERAL PUBLIC UTILITIES (Oyster Creek Station, Docket No. 5C-219)
GEORGIA POW'ER CO. (Hatch Nuclear Power Plant, Units 1 and 2, Docket Nos. 50-321 and 50-306)
GULF STATES UTILITIES CO. (River Bend Station, Docket No. 50-458)
ILLINDIS POWER CO. (Clinton Nuclear Power Plant, Docket No. 50-461)
IOWA ELECTRIC LIGHT & POWER CO. (Duane Arnold Nuclear Power Plant.
- DocketNo.50-331)
LONG ISLAND LIGHTING CO. (Shoreham Nuclear Power Plant, Docket No. 50-322)
MISSISSIPPI POWER A LIGHT CO. (Grand Gulf Nuclear Station, Docket No. 50-416)
NEBRASKAPUBLICPOWERDISTRICT(CooperStation,DocketNo.50-298)
NIAGARA MOHAWK POWER CORP. (Nine Mile Point, Units 1 and 2, Docket Nos. 50-220 ,
and50-410)
NOFTHEAST UTILITIES (Millstone Unit I, Docket No. 50-245) l 1
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,. f.; S.ER!, STATE 5 F0WEk CO. (Monticelle Nuclear Power Plant, Docket No. 50-263)
PE',';5 v;VA!;1 A POWE: 6 LIGHT CO. (Susquehanna 5 team Electric Station, Units 1 and 2, ocket hes. 50-357 ano SC-385) ;
PE LACELPH:A ELECTRIC CO. (reach Ecttom Nuclear Station, Units 2 and 3, Docket Nos.
50-277 anc 50-278), (Limerick NL, clear Power Plant, Unit 1, Docket No. 50-352)
POWEE AUTH0F:TY CF THE STATE OF NEW YORK (James A.. Fitzpatrick Station, Decket No. 50-333)
FL'ELIC SERVICE ELECTE:t & GAS CO. (Hope Creek Generating Station, Docket No. 50-304)
TENNESSEE VALLEY AUTFOR:~Y (Browns Ferry Nuclear Station, Units 1, 2, and 3, Docket hos. 5 -259,50-25C, and 50-296)
YEEM0t i AtxEE NU: LEAF F04ER CORF. (Vermont Yankee Nuclear Power Plant, Cccket he. 50-271)
W:54:t3T0h FL5;:: F:rER SUFFLY SYSTEt' (WNF Unit 2, Docket No. 50-397)
L* RECTOR'S CEC:510h UNDER 10 CFR 2.206 I. INTRODUCTION Cn July 22, 19EE, Ms. Susan Hiatt, on behalf of Ohio Citizens for Responsible Energy, Inc., (Petitioner) filed a Petition in accordance with 10 CFR 2.2C5 with the Nuclear Regulatory Comission (NRC). The petitton was referred to the Director, Office of Huclear Reactor Regulation (NRR) for consideration.
, The Petition asked the Director, NRR, to take imediate action to relieve alleged undue risks to the public health and safety, posed by the thennal-hydraulic instability of boiling-water reactors (BWRs), as revealed by the power oscil-lation eve ,t at LaSalle Unit 2 on March, 91988 (LaSalle Event). The Petitioner specifically recuested the NRC to order all BWR licensnes to (1) place their reactors in cold shutcewn, (2) develop and implement specified operating crecedu es relatir; to the thermal-bydraulic instability issues, (3) demerstrate l l
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't } demerstrate the capability of instrumentation related to power esci114tions, '
l (5} oevelep sirnulators capable of modeling power oscillations similar to those occurring at LaSalle as well as out-of-phase power escillatices, (E) report to the NEC all past and future incidents in which recirculation pumps have tripped 1
off, (7) sLtmit to the NRC justification for continued operation of BWRs, and (S) submit a repert to the NRC within 1 year demonstrating compliance with Criterien 1~ given in 10 CFR Fart 50, Appendix A (GDC-12)I. In addition, the petitdct er requested the Comission to reopen Generic Issues B-19 and B-59, to reopen the Anticipated Transierts Without Scram (ATWS) rulemaking proceedir.g, anc te rece'sicer the use of the end-of-cycle recirculation pump trip on SWRs.
Ms. Fiatt alleged as grounds for the Pet'ition that the LaSalle Event has seriets safety im;11 cations fer all BWRs and that the Nuclear Regulatory Cerrission (NRC) has f ailed to take appropriate regulatory action in response to the LaSalle Event. In the Petition, Ms. Hiatt cites the following postulated safety implicaticos, some of which had been previously identifie'd in several referenced documents attached to the Petition: (1) decay ratic's determined by licensing calculations are not reliable indicators of core stability (Attachment 2 to Petition) and design analyses of the reactor cannot be relied upon to ensure that esci11ations are not possible in BWRs; (2) The General Electric (GE) Company's guidance for operations provided in Service Information Letter (SIL) 380, Revision 1, is inadequate to ensure compliance with GCC-12 ( Attachment 4 to Petition); and (3) SWR plant instrumentation may 10 CFR Part 50, Appendix A, Criterion 12, " Suppression of Reactor Power Oscillations," states that: "The reactor core and associated coolant, control, and prctecticn systers shall te designed to assure that power oscil16tions which can result ir. conditions exceeding specified acceptable fuel design limits are not possible or can be reliably and readily detected and suppressed."
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net detect power esci11ations if they occur out of phase or too rapidly
( Attachments 1 and 4 to Petition). Ms.Hiattthenassertsthat(1)giventhe implications of the LaSalle Event, the actions requested of BWR licensees in NRC Bulletin No. 88-07 are insufficient, (2) most, if not all BWRs, are in a state of noncompliance with GDC-12, and (3) the NRC aust take aggressive enforcement action to protect the health and safety of the public.
On August 26, 1988, I acknowledged receipt of the Petition. 3 informed Ms. Hiatt that (1) her request for imediate relief was denied because the allegations that formed the basis for the Petition did not reveal ar.y new operational safety issues that posed an imediate safety concern for continued BWR operation, G ) the Petition would be treated under 10 CFR 2.206 of the Comission's regulations, and (3) appropriate action would be taken within a reasonable amount of time. For reasons discussed below, the Petition is denied.
Ms. Histt's request to reopen rulemaking proceedings regarding ATWS is being treated separately as a petition for rulemaking under 10 CFR 2.802 of the Comission's regulations.
!!. BACKGROUND The LaSalle nuclear power st: tion, operated by the Commonwealth Edison Company (CECO), is a two-unit site located 11 miles southeast of Ottawa, Illinois. Both units utilire General Electric-designed BWR/S reactors with containments of the Mark 11 design.
On March 9, 1986, LaSalle Unit 2 underwent a dual recirculation pump trip event that resulted in a loss of forced circulation cooling, a reduction in l
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l reacter ccee*, art a decrease in reactor inlet feedwater temperature.
Apereximately 5 minutes af ter the recirculation pump trip, with the reactor beir.; cocied via natural circulation, operators observed that the average power rarge meritor (ApRM) indications were oscillating between 25 and 50 percent power (25 percent peak to peak) every 2 to 3 seconds. At the same time, the local poner range monitor (LpRM) downscale alarms began to annunciate and clear, incitatin; that power was oscillating about the downscale alarm setpoint. Durirg this period, the operators recognized that they were operating ir. a regier c' ccre instability. They attempted to restart a recirculation purp ir creer c ir. crease flow to prevent instability, but this action was unsuccessful as a'.1 of the pump start permissive conditions had not been satisfied. (permissives are protective features designed to inhibit start-up of ecuipment weer certain specified conditions critical to proper functioning of the ecuiprer.: are not within specified limits). Approximately 7 minutes after the retirculatier, pump trip, as operators were preparing to perform a manual scrat, the reactor scrarrned automatically because of high neutron flux in the reactor. (A reacter scram involves rapid insertion of shutdown and control rods by either manual or automatic actuation of the reactor protection system).
The scram shut the reactor down, and recovery from the scram proceeded normally.
On March 16, 1985, after receiving additional information from the licensee concerning the event, the NRC dispatched an augmented inspection team (AIT) to the site. The AIT completed its inspection on March 24, 1988, and issued its inspection report on May 6, 1988. The AIT concluded that (1) fuel design limits had net been exceeded during the transient, and fuel damage had not occurred; (2) plant equipment functioned as designed; and (3) operator actiers during the event were within the bounds of their procedures and training, I
il r.: tre :rc:ecures ard training program themselves were inadequate. The AIT also icertifiec a nurier of generic technical concerns and recommended that they be torsicerec further by the staff.
On Jure E,1988, the NRC Office for Analysis and Evaluation of Operational Data (AECL) issued a special report documenting its concerns regarding the power oscillation esent at LaSalle 2 and its recommendations for follow-up action.
A resRcnse to tre recomencations was provided to AEOD by NRR on June 24, 1985.
On Jure 15,19EE, following completion of its evaluation of the March 9,1988, ever e: Lasi.11e, tre hE: issued Bulletin No. 88-07 to holders of operating licenses anc cerstrLetite perr'is fer SWRs. The bulletin requested that recipients take actior tc ers e that acecuate operating procedures and instrumentation are avail-atle and adecuate cperator training is provided to prevent the occurrence of power p
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oscillations during all meces of BWR operation.
The tulletin recuired that recipients confirm by letter to the NRC that the requestec actions were completed and implemented. All confirmation letters have been received and reviewec. They indicate that:
- 1. All EWR licensees have procedures in place to detect and suppress instability regardless of the value of previously calculated decay ratios;
." 2. All licensed reactor operators and shift technical advisors were briefed regarding the LaSalle Event within 15 days following receipt of the bulletin, or before resuming shift duties if they had been unavailable during the 15 day period; ,
- 3. All action to modify operating procedures and the operator training prograr with respect to detection and suppression of potential rea:ter instabilities had been completed or would be completed before f
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.startu; frcr the current outage and, in a few cases,.no later than De :er.c e r 15, 1988; and, 4
All licensees have confirmed that instrumentation relied'upon by plant operators te execute operating procedures is adequate based on an-assessrert by the equipment vendor (GE) and a review of any modifi-cations made to equipment.since installation.
The staff has tegur. te audit licensee responses to the bulletin in more detail.
The audits will centinue ever the next year.
- n hoverter 19BE, Gereral Electric Company (GE), working with the BWR Owners' G cu; (EJCG), issued a letter entitled " Interim Recommendations for Statility A:ticts' to the EWR licensees. The interim recommendations are based on the results of a generic evaluation of power oscillations performed for m EWROS at the request of the NRC staff. This evaluation has indicated that wnen'regioral power esci11ations 2 become detectable on the average power ran5e monitors, the safety margir. with respect to the plant minimum critical power ratio (MCFR) may be insufficient under some operating conditions to ensure that operator actien in response to ApRM signals would prevent violation of the MCPR safety limit. The interim recommendations include explicit restrictions and modified operator actions to ensure that operation in the vulnerable power / flow operating regime is avoided. The recommendations were reviewed by the NRC staff and have been found acceptable for those plants which have effective automatic scram protection for regional oscillations. For plants 2
Regional oscillations are ones in which power oscillates only in distinct regiers o' the reactor core, as opposed to a core-wide oscillation, in which
- .er escillates throughout the core as was the case in the LaSalle Event.
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v ict de net have effective automatic scram protection for regional oscillations, tre sta#f telieses that the interim recommendations may not prov' Je sufficient,
-reliable prctection. Consequently, the staff has requested that licensees irplement the interim recorrendations, and if appropriate, implement additional actions which compensate for the lack of automatic scram protection for regional oscillations. The staff's request is contained in Supplement I to NRC Bulletin 65-C7 wnich is discussed in the next paragraph.
Cr Cecenter 3C, 1965, the NRC issued Supplement I to NRC Bulletin 88-07.
The su;;1erert provides addressees with new information concerning power escillatiers ir EWES and requests that they take specified actions to ensure ttat the safety lirit for the plant minimum critical power ratio (NCFR) is not L viciated as a result of regional power oscillations. The supplement is an outcrowth c' generic evaluations of power estillations performed by the BWROG at tne NE: steff's request and the staff's independent study of regional power escillatiers. The preliminary results of these evaluations indicate that when
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regional pm *r esci11ations become detectable on the average power range monitors, the MCFR safety margin may be insufficient under some operating conditions to ensure that manual actions taken in response to APRM signals would prevent 3
violation of the MCPR safety limit. Licensees were requested to take the i following actions:
3 The supplement is not applicable to Big Rock Point ,(Docket No. 50-155) l because of cricue design features and because existing operating limitations enforced by technical specifications address the stability concerns which are the subject cf +he supplement.
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(1 )- u trin 3C days of receipt of the supplement, all BWR licensees should inplement the GE interim stability recommendations described in the GE letter entitled " Interim Recommendations for Stability Actions". However, for these plants that ce not have effective automatic scram protection in the event of regional oscillations, a manual scram should be initiated under all operating conditions when two recirculation pumps trip (or "no pumps operating") with the reactor in the RUN mode.
(2) The boundaries of Regions A, B, and C shown in Figure 1 of the GE recom- '
rendations were derived for those BWRs using NRC approved GE fuel. For BWRs using fuel supplied by other vendors, these regions should be adopted in principle, but the power / flow boundaries should be based on existing bcundaries that have been previously approved by the NRC. For proposed rew fuel designs, the stability boundaries should'be reevaluated and justified based on any applicable operating experience, calculated changes in core decay ratio using NRC approved methodology, and/or core decay ratio measurements. There sheuld be a high degree of assurance that instabil-ities will not occur under any circumstances of operation in Region C.
(2) The GE interim recommendations are ambiguous with respect to permissible ccrcitions for entry of Regions B and C. Although the recommendations state that intentional operation in Region S~is not pennitted and operation in Region C is permitted only for purpose of fuel conditioning durir; rod withorawal startup operations, intentional entry into Region B er C is also allowable in situations where rod insertion or a flow increase is required by procedures to exit Regions A and B after unin-tertional entry. Licensees should ensure that the procedures and training employee for in.plementatien of these recommendations avoid any similar antiguity which could lead to operator confusion.
Fursuant to 10 CFR SC.54(f), licensees are required to advise the NRC by letter within EC days of receipt of the supplement whether the requested actions have been completed and implemented. The staff will evaluate the responses and the results of studies which are continuing over the next several months to determine whether j any additional action by the staff is necessary.
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III. DISCUSSION Py staff arc : have considered the safety implications identified in the
'Fetition and tre specific re'1'ief requested and have done so in light of the most recent cata available to the staff from the BWROG and staff consultants. Our eve 1Lation follows.
A. Esses fer ;ecuest
- 1. Fella: .lity of Decay Ratio for Predicting Stability Decay retic it a reacter is a measure of the response of the neutron flux te a change er perturbation. As such, it is a convenient measure of the relative statii4ty c' a reactor core. A decay ratio of less than 1.0 indicates inherent stet:lity ir that the response to a perturbation will decay to the steady state value. A cecay ratio equal to 1.0 represents the special condition when the response to a perturbation will be continuing esci11ations of constant magnitude termed linit cycles. A decay ratio greater than 1.0 indicates an unstable condition in that the response to the perturbation diverges in a linear system. In a BWR, which is a non-linear system, decay ratios greater than 1.0 are indicative of larger amplitude limit cycle oscillations. Predictive methods developed by General Electric for determining BWR decay ratios were approved by the NRC with the provision that a 20 percent uncertainty be applied conservatively to the result.
Calculated core decay ratios of less than 0.80 (i.e.,1.0 minus an uncertainty of .2) by GE methces were approved as acceptable evidence of core stability anc cer;1iance witt GDC-12.
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l T*e ;-edi::e: decay ratio for the LaSalle Unit 2 reactor was 0.6C.
horever, ia ge.cs:illatier.s were observed during the LaSalle Event that indicate tnet actual ce:aj ratio was greater than l'.0. Consequently, the uncertainty in
' the ;redictise.rethod was significantly larger than expected; that is at least 4C rercent versus 20 percent.
The larger-than-expected calculational uncertainty has since been attributed te at it.ede: ate representation of actual reactor operating conditions in the LaSaile calculational model. In light of this potential for error, the staff has cor:1udet trat it will rc longer accept predictive calculations of core decay ratio as teses f:r ,cer:rstratirg compliance with GDC-12.
In creer #cr a li:enses to satisfy GDC-12 with respect to' core-wide power os:illetions, the sta#f's position is that each BWR unit must have the necessary c;eratirg liritatiens, response procedures, and operator training program to readily and reliatly cetect and suppress core-wide power oscillations regardless of calculatec decay ratio. The staff has communicated this position to licensees in hRC Bulletin No. 88-07. As discussed above, all licensees have now responded to Bulletin No. 85-C7 and have indicated that they have .the necessary procedures and operator training program to readily-and reliably detect and suppress core-wide power esci11ations regardless of calculated decay ratios.
- 2. Adequacy of Procedural Guidance from GE (Service Information Letter 360, Revision 1)
The Gere a Ele:tri: company issuee Service Information Letter (SIL) 380, Revisier 1 to its custoners on February 10, 1984 The letter reflected new q te:rr :ti ir' -ratior regarding BWF stability and provided new guidance to BWR 4
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cre"aters 'cr cetectin; ard sup;ressing neutron flux esci11ations. The letter supersecec tre ;"esicusly issued SIL SEC.
The tJC staff reviewed SIL 38C, Revision 1, as part of its action to reselve Generic Issue E-19, "BWR Thermal-Hydraulic Stability." On the basis of f 1 the staff's review and that of its contractor, Oak Ridge National Laboratory, the i staff ccncludec that " operating limitations which provide for the detection and sL:;ressler. cf flux esci11ations in operating regions of potential instability, cor.sistent with.the reconrencations of General Electric SIL 380 (Rev. 1), are acceptatie te demonstrate cor;1iance with GDC-10 and GDC-12 for cores loaded with a;;"n et CE #ael cesigns." The basis for this conclusion was the result c' a technical e.a hatier, that incicated that if properly implemented, the recommendations containe' in the SIL were sufficient to readily and reliably cetect ar.c su;;ress lirit cycle oscillations #
It is im;criant te note that operating procedures consistent with GE SIL 36C, Revision I were not in place at LaSalle Unit 2 at the time of the March 9, 1988 incident. Consequently, the response and performance of reactor operators during the LaSalle Event does not reflect on the adequacy of the SIL recomenda tions.
The f1RC staff continues to endorse the general operational guidance given in GE. SIL 380, Revision 1 and believes that if properly implemented, it is sufficient to identify and terminate core-wide limit cycle oscillations. However,
' fMC Memorandur and attachments from Harc1d R. Denton to Victor Stello, cated P'ay 21, 1965, l
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l ai ciscusset presicusly in section II of this document, supplementary procedural a: tier.s are necessary to ensure that the safety limit for the plant minimum critical power ratic is not viciated as a result of regional power esci11ations.
- 3. Acecuacy of Plant Instrumentation I
Ir Bds desigr.ed by GE, the neutron monitoring system (NMS) is used to monit,or tre core.fer r.eutrer flux csci11ations. The NM5 uses incore detectors to monitor rectrcr 'la>.'ror startu; througr, full-power operatio1 and is a safety-related syste . Tre fJ: staff reviews the design of the HMS as part of its normal licensing review.
Ir gereral, the staff considers the NM5 to be adequate for implementation c' the guicelires provided in GE SIL 380, Revision 1. However, during follow-up review cf the LaSalle Event the ARC augmented inspection team identified sone time response and filtering characteristics of the HMS inst'ruments in LaSalle Lr.it 2 that they were concerned about. The AIT also expressed concern about the ability of the APRMs to properly detect regional oscillations which cause LPRM signals to oscillate out-of-phase. Because of these concerns,
, the staff requested, in NRC Bulletin No. 88-07 and in meetings with the BWROG, that licensees verify the adequacy of the instrumentation that is relied upon by operators within their procedures.
In response to Bulletin 88-07, all licensees have evaluated their irstrumentatien with regarc to time response and filtering characteristics and
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- ave irdicatec tra: instrurentatier. relied upon by plant operators to execute l cperatir; prececures is ace:;uate. The BWROG and the NRC staff have I
'incepencertly evaluatec the ability of NMS instrumentation to properly detect i regioral oscillations which occur as asyrmetric out-of-phase oscillations. j
(; The results cf these evaluations are discussed below.
Power oscillations with an amplitude and phase that vary spatially in tne reacter are termed regional oscillatiers, and usually occur as asymmetric 4
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cut-of-phase esci11ations. These oscillations are difficult to monitor accurately witt averace poose range instruments in the NMS but can be detected with local power rarge irst uments. The results of generic evaluations of power esc 111ations perferr.ed by GE for the BWR owners group (BWROG) at the request of *.te NRC staff and the staff's independent evaluation have indica Md that when recional power oscillations become detectable on.the APRMs, the se#ety rar;in witn respect to the plant minimum critical power ratio (MCPR) may be insufficient under sore operating conditions to ensure that operator action in response to APRM signals would prevent violation of the MCPR safety limit. In light of this GE issued ir.terim recorrendations to BWR licensees which include explicit restrictions on reactor power level and coolant flowrate, and actions for plant operators to take if unacceptable power / flow operating regimes are entered unintentionally. The interim recommendations were reviewed by the NRC staff and found acceptable for those plants which have effective automatic scram protection for regional oscillations. For plants which do not have effective automatic scrat protection for regional oscillations, the staff believes that the interir reconrencations rey not provide sufficient, reliable protection.
Consequently, the sta'f has recuested that licensees implement the interim recer..endaticrs, and if appropriate, implement additional actions which
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c: reestte #:r t*e lack cf auto atic scram protection for regional oscillations.
'te staff's request is contained in Supplement 1 to NRC Bulletin 88-07 which j was ciscLssed previously in the section 11. of this document. The staff believes that it;1ementatien of the requests in NRC Bulletin 88-07 and Supplement 1 to the bulletin will ensure continued safe plant operation in the interim until long-tere ccrre:tive actions are developed and put in place. The NRC staff will j continue te *:-k with the Ba'R05 to develop long-term corrective actions.
The ste#f expects to issue another generic communication within 12 to 24 months tha: will ; tvice guidance for long-term resolution of this stability issue.
4 Safety Significance of Power Oscillations Poner oscillations in SWRs are not considered to be a serious generic safety centern tecause oscillations can be detected and suppressed. Tests and operating experience (LaSalle Event) indicate that core-wide power oscillations can be terminated manually in a tir fashion by control room operators or ultimately by automatic action of the high-power level trip function in the reactor protection system.
Asymmetric out-of-phase oscillations are unlikely because of restrictions on reactor operating conditions. Moreover, procedures specified in Supplement I to NRC Bulletin 88-07 ensure that such oscillations would be suppressed quickly with an anticipatory reactor scram initiated manually by a reactor operator.
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e E. 4: 4tierer's ke:uest
- 1. Orcer All EWR Licensees To Place Their Reactors in Cold Shutdown
~As described above, the NRC issued Bulletin No. 88-07 in response to the LaSalle ever.t. As indicated by their responses to Bulletin No. 88-07, all SWE litersees have developed and implemented procedures to detect and sup- !
press core-wide power.oscilhtions. Consequently, no BWR licensee now relies cr a calculated decay ratio to demonstrate compliance with GDC-12.
As already ex;1ained, Supplement I to Bulletin No. 88-07 specified additional protecures te deal with regional power oscillations. The reconnendations of Supplemer.t I are currently being implemented. In light of the relatively stcrt period for implementation (60 days), and existing restrictions on reactor cperating conditions that minimize the probability of regional
.i' oscillatiers, the staff has concluded that continued operation of all BWRs while licensees are implementing the recommendations of Supplement 1 is acceptable. !
o In summary, based on our review of the generic implications of the LaSalle Event to date, we have not identified any operational' safety concerns nor instances cf regulatory non-compliance which warrant a shutdown of boiling water reactors. Consequently, your request is denied.
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- 2. Creer All EW: Licersees te Develop and Implement Specified c
FrotecLees. "
Tris recuest is der.ied for the following reasons:
(a) The NPsC staff currently believes that procedural guidance provided te litersees in SIL 350, Revision I for detecting and suppressing tcwer estillatiers is adequate for mitigating core-wide oscillations.
(t' Tre N:: sta" has deterrined that explicit procedures different from these specified by the Petitioner are necessary to control regional ,
poveer esti11ations and ensure continued plant operation in accordance with GDC 12. The staff has specified the necessary procedures it. Supplemer.t 1 to NRC Bulletin 88-07 and requested that ;
licensees implement the specified procedures within 30 days of receiot of the supplement.
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Petitioner requests implementation of the following specific procedures:
(a) Immediately insert control rods to below the 80% rod line following reduction or loss of recirculation flow or other transients which result in entry into potentially unstable regions of the power / flow map; (b) Increase l recirculation flow during routine reactor startups and insert some control )
rods prior to reducing recirculation flow below 50% during shutdowns to avoid !
cperation ir cetentially unstable areas of the power / flow map; (c) innediately {
scram the reacter if (a) or (b) above are not successful in preventing and l suppressing Oscillations. The licensees shall submit these procedures to the j NRC for review and appreval.
The.conterts of Supplement I to NRC Bulletin 88-07, including the specif1ec procecures, are discussed in section 11 of this document.
The staff has judged that continued plant operation during the 30 day irplementatice period is acceptable based on the low likelihood of a regicnal oscillation in the relatively short period of 30 days.
- 3. Order all EG Licersees To Demonstrate That Certain Training Related to the Specified Procedures Has Been Provided.
Tt.is re:mest is denied for the following reasons:
1 (a) The responses to NRC Bulletin No. 88-07 indicate that all licensed reactor operators and shift technical advisors performing shift cuties at SWRs were briefed thoroughly regarding the LaSalle Event within 15 days of receipt of NRC Bulletin No. 88-07 or soon thereafter.
(t) The responses to NRC Bulletin No. 88-07 indicate that all BWR licensees have confirmed the adequacy of their existing operator training program regarding detection and suppression of power esti11ations or have made the program modifications necessary to properly address this subject and accomodate changes in procedures in response to Supplement l'to the bulletin.
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- c. Creer Ali EWR Licensees To Demonstrate the Capability of Instrumentation i I
Felatec te Power Oscillations
)
l This recues 1s cenied for the following reasons: i l i
( a ,' ire NEC staff considers the neutron monitoring system designed for j I
EWRsbyGEtobeadequatefordetectingcore-widepoweroscillatigns 1r SWCs. I (t; Cr. tr,e basis of responses to NRC Bulletin No. 88-07, the NRC staff believes that all licensees have confirmed that the response anc filtering characteristics of instrumentation relied upon by crerators tc execute operating procedures are acceptable.
(c) Implementation of operating procedures specified in Supplement I to NRC Sulletin 88-07 will compensate for inability of APRMs to properly detect regionel oscillations.
- 5. Order All BWR Licensees To Develop Simulators Capable of Modeling Power Oscillations Similar to Those Occurring at LaSalle and Out-of-Phase Oscillations i I
1
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Tr's rec.;est is denied for the following reason:
(a)_ Current NRC regulations, that is, 10 CFR 655.45(b), in conjunction with NRC Regulatory Guide 1.149 and NUREG-1258, already recuire utilities to have a simulation facility capable of modeling the effects of loss of forced reactor coolant flow and to certify the simulation facility for use in operatorlicensingexaminationafterNay 26, 1991. However, i 1
although simulator training for control of power oscillations I wi'.1 ir. prove ar. operator's ability to detect and suppress '
oscillations in a timely fashion, non-simulation based training can be fashioned which is sufficient to address stability cencerns. Consequently, the staff concludes that training ,
i programs now in place, including improvements made in response !
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to NRC Bulletin 88-07, are adequate in the interim until the ,
entantements of 10 CFR 655.45(b) take full effect in 1991.
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- 6. Order All BWR Licensees To Report to the NRC Regarding all Future and
', Past Incidents in which Recirculation Pumps have Tripped Off or that ]
Involved Power Oscillations. -
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7t's re;uest is denied for the following reasons: ,
(a) Existing NRC regulations, that is, 10 CFR 550.72 and 10 CFR 150.73, a'. ready require that significant events involving recirculation pump trips or power esci11ations be reported to the Commission. Such ever.ts are these ir which the pump trips or oscillations lead to (a) cor;1etier, of any nuclear plant shutdown required by the plant's ,
tec'rical specifications; or, (b) any operation or condition prohibited t;. t hE -lart's technical specifications; or, (C) the plant being in a ccrcitier, r.ct covered by the plant's operating and emergency procedures, or (d) ary event or condition that resulted in an unplanned manual or automatic actuation of any engineered safety feature, including the reacter protection system. Petitioner demonstrates no basis for requiring repetition of reports already required by 150.72 and 15C.73.
(b) Since the accident at Three Mile Island, Unit 2 in 1979, programs have been developed and implemented in several NRC offices to r systematically review and evaluate operating reactor event reports. Such programs include Analysis and Evaluation of Operational Data (AE00), Operating Reactors Assessment and Events Analysis (tJR) and the Resident Inspector program (NRC Regional Cffices). These reviews have been performed to ensure prompt response tc accidents, to identify significant precursor events and w_~-_-.-.~ _ _ _ _ . _-. - - _ _ _ _ _ _ - _ . _ _ _ _ _
tc icertify adverse trends and patterns in operating experience, ir cheir; ary associatec with BWR instability. The staff considers these past reviews of licensee event reports to have been adequate.
The Petitien gives no basis to re-examine these reports and the staff concluces that action to collect and review past event reports is unne ces s a ry .
- 7. Rec;en Generic Issue B-19. "BWR Thermal-Hydraulic Stability" itis recuest is cenied because a generic reassessment of SWR stability is net recessar,s r cecer for the staff to specify criteria licensees must rneet to te in cor;11ance with existing regulations.
hE: staf# action on Generic Issue B-19 culminated in tne identification c' two acceptable methods by which licensees could show compliance with GDC-10 and GD:-12. Licensees could either (1) show that thermal-hydraulic instabilities are net possible by design by calculating acceptably low decay ratios with analytical rethods approved by the staff, or (2) show that proper capabilities for detection and suppression of oscillations are embodied in plant operating procedures and operating limits. As discussed in section A.I. of this Decision, the staff has concluded that in light of the LaSalle Event, use of a calculated decay ratio to demonstrate compliance with general design criteria is no longer acce; table and that all BWR licensees must show that proper detection and suppression capabilities exist at their plants, that is, method 2 listed L previously. Because the staff concludes that the implementation of method 2
-listed above cortinues to be a valid means for complying with GDC-12, method 2 l remains a valid resolution of Generic Issue B-19. Consequently, repetition of l
l tre ger.eric issue resciution process for Issue B-19 is unnecessary.
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This request is denied because the LaSalle Event has not revealed any deficiency in the technical resolution of Generic Issue B-59.
In resolving Generic Issue B-59 for BWRs, the staff evaluated the accept-ability of operating the reactor for electricity production et reduced power with only one of two recirculation loops in operation (i.e. at a reduced <
coolant flowrate'. The results of the evaluation were that stable single loop ;
operation is achievable and acceptable with specified operating limits and procedures for avoiding as well as detecting and suppressing power oscillations that may arise (e.g., if perhaps the operating recirculation pump tripped). In the LaSalle Event, instability arose following inadvertent trip of both recirculation pumps when the reactor operated with no recirculation loops in operation. Power operation with both recirculation loops inoperable is prohibited by each license for operation of a BWR. The LaSalle Event reaffirms the necessity for prohibiting operation with no recirculation loops in operation. However, the LaSalle Event does not invalidate the technical findings from the review of Generic Issue B-59.
- 9. Reopen Rulemaking Proceedings Regarding Anticipated Transients Without Scram 1
In the acknowledgement letter sent to Petitioner on August 26, 1988, I included this request among those to be considered pursuant to 10 CFR 2.206. I have subsequently determined, however, that this request is more properly treated as ;
a petition for rulemaking under 10 CFR 2.802. As such, it has been referred to 1
the NRC Office of Research for appropriate action. However, it is important to
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1 note that beth the NRC and BWR Owners Group (BWROG) currently have programs in )
l which analyses of ATW5 conditions are being conducted. These analyses treat large l amplitude power oscillations with state-of-the-art analytical methods. The results of these analyses to dats confirm the technical bases for the current ATW5 rule. Consequently, at this time, the NRC staff sees no basis for recom-I mending that the Commission reopen rulemaking proceedings regarding ATWS. If, j
l however, the staff finds evidence which contradicts the assumptions and results of previous ATW5 analyses from either the information you provided in support of the request or nem information from ongoing NRC and BWROG programs, it may then te appropriate for the Commission to reconsider the current ATWS rule.
- 10. Reconsider Use of the End-of-Cycle Recirculation Pump Trip on BWRs The ene-of-cycle recirculation pump trip (EOC-RPT) is part of the reactor protection system and is an essential safety supplement to the reactor trip. The EOC-RPT reduces reactor coolant flowrate to provide additional negative reactivity for mitigation of events in which the reactor coolant system is pressurized rapidly.
The additional negative reactivity from the EOC-RPT is needed primarily at the and of the cycle to compensate for (1) changes in reactor power distribution over the
'. cycle that have reduced thermal margin and (2) a decrease in the rate of negative reactivity insertion during reactor scram. The two events for which the E0C-RPT protective feature will function are closure of the turbine stop valves and fast closure of the turbine control valves. In both cases, the E0C.RPT is accompanied by an anticipatory scram of the reactor that is initiated by the same signals that initiate the EOC-RPT.
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- 11. Ren. ire Licensees To Submit Justification For Continued Operation in Light of the Issues Raised in the petition 1
l In NRC Bulletin 87-07 and Supplement I to that bulletin, the NRC Staff specified actions licensees should take to ensure continued safe operation ar.d coepliance with the Comission's regulations. All licensees have confirmed, under catt ar.d affirmation, that (I) all necessary actions requested in NRC Bulletin 87-C7 have been completed and, (2) that fu11' documentation of the ,
ection taker. is aveilable for inspection by the NRC. Licensees are also recuired tc acvise the FRC by letter, within 60 days of receipt of Supplement I to the. tulletin, whether actions requested in the supplement have been completed anc implerrented. The staff corsiders responses to both the bulletin and the' supplerent, which ere acceptable to the staff, to be adequate justification en the part of licer. sees for continued operation. Consequently, yeur request is denied.
- 12. Order All EWR Licensees to Submit a Report to the NRC Within One l
Year Demer.strating Compliance with Criterion 12 Given in 10 CFR Part 50, Appendix A (GDC 12)
As indicated previously in paragraph A.I., the NRC staff's position regarding corpliance with GDC-12 is that, regardless of the magnitude of the calculated decay ratio, each BWR licensee should have in place the necessary l
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operating lin1tstions, response procedures, and operator training program that permit plant operaters to identify and terminate limit cycle oscillations.
The staff's position was corrnunicated to licensees in NRC Bulletin No. 88-07, through treetings with the BWROG and in Supplement I to t:RC Bulletin 88-07. The staff believes that actions licensees are expected to take in response to NRC Bulletin 88-07 are sufficient to ensure compliance with GDC-12 for core-wide oscillations. However, if plant inspections reveal that actions taken by licenstes are inadequate, plant-specific actions would be pursued at that time.
With respect to regional oscillations, procedures specified in Supplement 1 to f,EC Bu11etir 88-07 ensure that such escillatiens would be suppressed quickly with an participatory reactor scram initiated tranually by a reactor operator. As discussec previously, the staff believes that implementation of these procedures will ensure continued safe plant operation in the interim until long-term ccrrective actions are developed ano put in place.
IV. CONCLUSION The Petitioner seoks the institution of a show-cause proceeding pursuant to 10 CFR 2.202 to modify or revoke the operating license of all SWR facilities.
, The institution of proceedings pursuant to 10 CFR 2.202 is appropriate only where substantial health and safety issues have been raised. See consolidated Edison Company of New York (Incian Point, Units 1, 2, and 3)., CLI-75-6, 2 NRC 173 (1975) and Washincton Public power System (WPPS Nuclear Project No. 2), DD-84-7, 1
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19 NR; 899, 923 (1984). This is the standard that I have applied to the concerns raisec by the Petitioner in this decision to determine whether enforcement action is warranted.
For the reasons discussed above, I conclude that no substantial health and safety issues have been raised by the Petitioner. Accordingly, the Petitioner's request for action pursuant to 10 CFR 2.206 is denied. As provided in 10 CFR 2.205(c), a copy of this Decision will be filed with the Secretary of the' Comission for the Comission's review.
FOR THE NUCLEAR REGULATORY COMMISSION l
Thomas E. Murley, Director !
Office of Nuclear Reactor Regulation Dated at Rockville, Maryland, this 27th cay of April 1989.
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, ENCLOSURE 3 DD-89-03 l
NUCLEAR REGULATORY COMMISSION DOCKET NO. 50-293, et al.*
BOSTON EDISON COMPANY, et al.'
(PilgrimNuclearPowerStation,etal.)*
ISSUANCE OF DIRECTOR'S DECISION UNDER 10 CFR 2.206 Notice is hereby given that the Director, Office of Nuclear Reactor Regulation (NRR), has issued a Director's Decision concerning a Petition dated July 22, 1988, filed by Ms. Susan Hiatt, on behalf of Ohio Citizens for Responsible Energy Inc. The Petition asked the Director, NRR, to take imediate action to relieve what the Petitioner alleged to be undue risks to the public health and safety posed by the thermal-hydraulic instability of boiling-water reactors (BWRs), as revealed by the power oscillation event at LaSalleUnit2onMarch9,1988(LaSalleEvent). The specific relief requested was te order all BWR licensees to (1) place their reactors in cold shutdown, (2) develop and implement specified procedures relating to the thermal-hydraulic ,
instability issues, (3) demonstrate that certain specified training has been provided relating to these procedures, (4) demonstrate the capability of instru- ,
mentationrelatedtopoweresc111ations,(5)developsimulatorscapableofmodeling.
power oscillations similar to those occurring at LaSalle and out-of-phase power
^
oscillations, (6) report to the NRC regarding all past and future incidents in whichrecirculationpumpshavetrippedoff,(7)submittotheNRCjustification for continued operation of BWRs, and (8) submit a report to the NRC within one year demonstrating compliance with criterion 12 given in 10 CFR Part 50, Appendix A (GDC-12). In addition, the Comission was requested to reopen Generic Issues B-19 and B-59, reopen the ATWS rulemaking proceeding, and ed
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reconsider the use of the end-of-cycle circulation pump trip on BWRs.
Ms. Hiatt gave as grounds for the Petition that the LaSalle Event has serious safety implications for all BWRs and that the Nuclear Regulatory Commission (NRC) had failed to take appropriate regulatory action in response to the LaSalle Event.
On August 26, 1988, the Director, Office of Nuclear Reactor Regulation (NRR), acknowledged receipt of the Petition. He informed Ms. Hiatt that (1) her request for immediate relief was denied because the allegations that fomed the basis for the Petition did not reveal any new operational safety issues which posed an imediate safety concern for continued BWR operation, (2) the Petition would be treated under 10 CFR 2.206 of the Comission's regulations, and (3) appropriate action would be taken within a reasonable time.
In the August 26, 1988 letter, the Director, NRR, acknowledged Ms. Hiatt's request to reopen the ATWS rulemaking proceedings as a request which would be i
treated pursuant to 10 CFR 2.206. This request, however, will not be treated j I
pursuant to 10 CFR 2.206 but is being treated separately as a petition for '
rulemaking under 10 CFR 2.802 of the Comission's regulations. I The Director has now determined that all of Ms. Hiatt's requests, except for her request to reopen the ATWS rulemaking, should be denied for the reasons set forth in the " Director's Decision Pursuant to 10 CFR 2.206" (DD-89-03).
The Decision is available for inspection and copying in the Cosuiission's Public Document Room, 2120 L Street N.W., Washington, D.C. 20555 and at the Local Public l Document Rooms near the facilities listed below. The addresses and hours of operations for the local public document rooms may be obtained by calling the following toll-free number: 1-800-638-8081. l l
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3 A copy of the Decision will be filed with the Secretary of the Comission for the Comission's review in accordance with 10 CFR 2.206(c). As provided in 10 CFR 2.206(c), thc Cecision will become the final action of the Cosmission twenty.five (25) days af ter issuance unless the Coemission on its own action institutes review of the Decision within that time.
FOR THE NUCLEAR REGULATORY COPMISSION j l
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i 2 :w f Thomas E. Murley, Director Office of kuclear Reactor Regulation Deted at Ror.kville, Maryland, this 27th of April 1989.
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CAROLINA POWER & LIGHT CO. (Brunswick Station, Units 1 and 2, Docket Nos. 50-324 and 50-325)
CLEVELAND ELECTRIC ILLUMINATING CO., ET AL. (Perry Nuclear Power Plant, Unit 1 Docket No. 50-440)
COMMONWEALTH EDISON CO. (Dresden Nuclear Power Plant, Units 2 and 3, Docket Nos.'50-237 and 50-249), (Quad Cities Nuclear Power Plant, Units 1 and 2, Docket Nos.50-254 and 50-265), (LaSalle County Station, Units 1 and 2, Docket Nos. 50-373 and 50-374)
CONSUMERS POWER C0. (Big Rock Point, Docket No. 50-155)
DETROIT EDISON CO. (Fermi Unit 2, Docket No. 50-341)
GENERAL PUDLIC UTILITIES (Oyster Creek Station, Docket No. 50-219)
GEORGIA POWER CO. (Hatch Nuclear Power Plant, Units 1 and 2, Docket Nos. 50-321 and 50-366)
GULF STATES UTILITIES CO. (River Bend Station, Docket No. 50-458)
ILLINOISPOWERCO.(ClintonNuclearPowerPlant,DocketNo.50-461)
IDWA ELECTRIC LIGHT & POWER CO. (Duane Arnold Nuclear Power Plant, DocketNo.50-331)
LONGISLANDLIGHTINGCO.(ShorehamNuclearPowerPlant,DocketNo.50-322)
MISSISSIPPI POWER & LIGHT CO. (Grand Gulf Nuclear Station Docket No. 50-416)
NEBRASKA PUBLIC POWER DISTRICT (Cooper Station, Docket No. 50-298)
NIAGARA MOHAWK POWER CORP. (Nine Mile Point, Units 1 and 2, Docket Nos. 50-220 and 50-410)
NORTHEAST UTILITIES (Millstone Unit 1, Docket No. 50-245)
NORTHERN STATES POWER CO. (Monticello Nuclear Power Plant, Docket No. 50-263)
PENNSYLVANIA POWER & LIGHT CO. (Susquehanna Steam Electric Station, Units 1 and 2, Docket Nos. 50-387 and 50-388)
PHILADELPHIA ELECTRIC CO. (Peach Bottom Nuclear Station, Units 2 and 3 Docket Nos. 50-277 and 50-278), (Limerick Nuclear Power Plant, Unit 1 Docket No. 50-352) y POWER AUTHORITY OF THE STATE OF NEW YORK (James A. Fitzpatrick Station, Docket No. 50-J33)
PUBLIC SERVICE ELECTRIC & GAS CO. (Hope Creek Generating Station.
Docket No. 50-354)
TENNESME VALLEY AUTHORITY (Browns Ferry Nuclear Station, Units 1, 2, and 3 Docket Nos. 50-259,50-260,and50-296)
YERMONT YANKEE NUCLEAR POWER CORP. (Vermont Yankee Nuclear Power Plant, DocketNo.50-271)
WASHINGTON PUBLIC POWER SUPPLY SYSTEM (WNP Unit 2, Docket No. 50-397) i 1
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