ML20055C801
| ML20055C801 | |
| Person / Time | |
|---|---|
| Site: | Perry, LaSalle  |
| Issue date: | 06/15/1990 |
| From: | Taylor J NRC OFFICE OF THE EXECUTIVE DIRECTOR FOR OPERATIONS (EDO) |
| To: | Chema T OHIO, STATE OF |
| References | |
| IEB-88-007, IEB-88-7, NUDOCS 9006250177 | |
| Download: ML20055C801 (1) | |
Text
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'-- , Mr. Thomas V. Chema Chainnan g 33 g )
- Public Utilities Comission State of Ohio 180 East Broad Street Columbus, Ohie 43266-0573
Dear Mr. Chema:
I am responding to the concern in your letter of December 17, 1988 regarding the power oscillation transient of March 1988 at the LaSalle County Nuclear i Station, Unit ?. We committed to keep you informed on this matter in our prior letter to you dated February 6,1989.
The U. S. Nuclear Regulatory Comission (NRC) staff has recently determined that there are acceptable long-term resolutions for this particular issue and summarized its position on the generic implications of the power tran-sient event at the LaSalle plant in the enclosed staff paper (Enclosure 1).
The implementation of the long-term resolutions of this issue as described in the staff paper will further enhance the safety of boiling water reactors (BWRs) including the Perry Nuclear Power Plant. Pending final implementation l of the technical resolutions, the BWR reactor plants have continued to operate l safely during the interim by following the requirements in NRC Bulletin 88-07 and its supplement issued in June 1988 and December 1988, respectively (Enclosures 2and3).
Please let me know if I can be of further assistance.
i Sincerely,,
Original Signed 8 Jamalsnm Uf J Executive Director for Operations
Enclosures:
As stated DISTRIBUTION:
L4 Docket-Files w/' incomin'g' ABDavis, RIII OGC NRC PDR*j//Echi" JPartlow TColburn ED0#04158 DCrutchfield HRichings EDO R/F JZwolinski SNewberry SECY(CRC 88-1255) WRussell TMurley/FMiraglia- JHannon @,
JTaylor PKreutur JBlaha AThadani EJordan, AEOD MDLynch EBeckjord,RES LPhillips ,
LA:PD3-3 PM:PD3-3 NRR/DRSP D:PD3-3 TechEd AD/DRSP PKreutzer* MDLynch* LPhillips* JHannon* JMain* JZwolinski* )
05/29/90 06/06/90 05/21/90 06/06/90 05/30/90 05/23/90 D:DRSP ADP/NRR DCrutchfield* JGPartlo:\am F ia 1y Mhylor 06/05/90 06/{/90 0 90 06/ 0 \
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Aoril 27. 1990 LEpY-90-152 5 (lMf0fm8IlOn)
For: The Comissioners ,
From: James Taylor Executive Director for Operations
Subject:
STATUS OF THE STAFF REVIEW OF THE REGULATORY IMPLICATIONS OF THE POWER OSCILLATIONS EVENT AT LASALLE 2
Purpose:
To infom the Comission of the status and future plans related '
to the staff review of the generic implications of the power oscillations event at the LaSalle County Station, Unit 2 on March 9, 1988, concerning the continued safe operation of other boilingwaterreactors(BVRs)intheUnitedStates. This report addresses the issues reised in the July 5, 1924, memorandum from ;
Chairman Zech to the Executive Director for Operations (EDO) that requested the Comission be kept fully informed of the staff's evaluation and of any proposed regulatory actions.
Eackgrour.d: Following the March 1988 instability event at LaSalle Unit 2, 3 the BWR Owners' Group (BWROG) initiated a task to investigate o actions that should be taken to resolve the BWR stability issue as an operational concern. Through analysis the BWROG found that the "high neutron flux" rea,-tor trip fro,m everage power rangemonitor(APRM)signalsdoesnotprovideprotectionagainst the local high neutron flux that can occur during out-of-plase modes of instability. Further the calcr.lations showed that theCriticalPowerRatio(CPR),safetylimitscouldbeexceeded ,
in violation of the General Design Ctiteria 10 and 12. Because of these results, interim operating recommendations to reduce the risk associated with instability were proposed by the BWROG andtheGeneralElectricCo.(GE)inaGElettertoBWRUtilities, of November 1988. The staff issued to all licensees Supplement 1 to Bulletin 88 07, which approved the proposed BWROG-GE interim operating recomendations with some additions. Regional e inspections verified the implementation of the recommended ,
actions.
. NOTE: TO BE MADE PUBLICLY AVAILABLE IN 10 WORKING DAYS FROM THE -
Contact:
DATE OF THIS PAPER L. Phillips, SRXB/ DST 2-3235 4
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The'Comissioners I On July 22,1988, a Petition filed by Ms. Susan L. Hiatt on behalf of the Ohio Citizens for Responsible Energy, Inc.,
requested that the Director of the Office of Nuclear Reactor -
Regulation take immediate action with respect to BWRs to ]
relieve alleged undue risks to the public health and safety ;
posed by the thermal-hydraulic instability of BWRs as revealed ;
by the LaSalle event. The Petition was denied by the Director's Decision dated April 27, 1989, under 10CFR2.206 with the exception of a portion of the Petition requestir.;; te Wopen rulemaking proceedings regarding anticipated transient without :
scram (ATWS) as part of the relief requested. The staff is )
treating this part of the request as a petition for rulew king i under 10CFR2.802 of the Comission repulations and referred it to the NRC Office of Research for eva untion. Ir,his April.27,. i 1989, letter to Ms. Hiatt, Dr. Murley noted that while there was ;
no evidence to contradict the assumptions and results of ,
previous ATWS analyses, the ATWS rule would be reconsidered if <
such evidence was revealed from ongoing NRC and BWROG programs !
for analysis of ATWS conditions. The results of these programs will be factored into rulemaking considerations. Notiev of the l Petition was published for pubile coment in the Federal ;
, Register on July 25,1989(FRDoc.89-17289 filed 7/24/89).
1 ?
Discussion: Long Term Solution to the BWR SteH11ty Issue -
In the report Attachment to Letter BWROG-9009, " Licensing Basis for Long Term Solutions to BWR Stability," dated January 1990, t the BWROG sumarized the current industry positions for the -
long-term resolution of the stability issue for normal operation '
p and anticipated operational occurrences for BWRs. The BWROG .,
developed these positions based on analytical studies that GE i t
performed for the BWROG during the past year. The BWROG has ;
proposed three different solution options that will be available for the licensees to choose among for implementation in their reactors: ,
(1) Regional Exclusion. This option would provide an automatic scram to prevent operation in a predefined area of the power and flow map where instabilities are considered
- likely.
(II) Quadrant APRM Based Protection. This solution applies only to reactors of the BWR 2 type, where the existing quadrant-average APRM scram may provide sufficient ,
e protection against both in-phase and out-of-phase instability modes.
LPRM-Based Protection. This solution would provide a (III) iiew signel from the oscillation power range monitor (OPRM) '
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l to the scram system. The OPRM signal will be extracted [
u fromtheindividuallocalpowerrangemonitors(LPRMs). ,
The OPRM would be a smart system capable of detecting
- i oscillation characteristics and thus providing !
automatic protection against all expec,ted types of
- instability modes.
+
- 0) tion I requires a substantial analytical effort to ensure that i tie high power and low-flow operating conditions excluded from '
normal operation have been conservatively defined. The NRC staff reviewed the analytical methods used by the BWROG, and our !
consultant at the Oak Ridge National Leboratory performed audit i calculations that'were in very close 40reement with BWROG ;
preliminary calculations of the exclus'on region boundaries for s reactors of the BWR3 and BWR5 types. The staff firds this '
l approach acceptable in principle and has notified 8WROG to .
perf orm final calculations of exclusion regions for all !
pertinent BWR types. l Option 11 is a very simple and practical solution for BWR2-type l
reactors. Although the quadrant APRM-based protection responde less sensitively to oscillation amplitude for out-of-phase modes than for in-phase modes, the staff finds this ,
acceptable, pending confirmatory calculations.The protection procedureto be .
outlined in the BWROG report to finalize the licensing calcula- .
tions for this option is technically sound and appropriate. ;
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- 0) tion 111 is a conceptually simple solution that should provide .
tie reactor with ample safety margins in the event of an instability.. However, the proposed design involves advanced technology consisting of new software and methods employed in a
- micro >rocessor based Class IE hardware system. Staff rvview Will >e~ required to address concerns with the design impleuientation. ,
t The BWROG expects to document the final analyses needed for licensing closu 7 for Options I_and 111 no earlier than September 1990. ,ne staff anticipates that licensees selecting Solution Option 11 will prepare plant-specific documentation.
^
The staff expects to complete its review of the long-term solutions for closure of stability operational requiremests within three months after receipt of the respective submittals.
Based on the BWROG schedule, the earliest date for generic 3 resolution is the end of 1990.
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EVALUATION OF THE EFFECT OF LARGE CORE THERMAL HYDRAULIC !
E LLATION5 DN RECOVERY FROM BWR ATw5 50ENARIQ5 ,
The LaSalle power oscillations began as a result of an automatic :
,- trip of-the recirculation pumps in response to a false ATWS (Iow ;
waterlevel) signal. Because large power oscillations may occur at the low-flow and high-subcooling conditions that result from this normal design response to an ATWS scenario, questions ,
have been raised regarding the validity of previous ATWS evalue-tions. The basic issue involves the effect of large power oscillations on'the behavior of an ATWS transient event and '
whethertheoscillationswerecorrectlymodeledinprevIous studies s a porting the development of automatic and operator ,
actions in response to an ATWS event.
l The PWROG, the NRC, and their associated contractors have been ,
studying the characteristics, sensitivities, and safety significance of power oscillations to evaluate the effect of oscillations and various response actions on the course of several ATWS scenarios. The studies have been slowed by the need to evaluate and validate the capability of the analytical models used to predict the characteristics of power oscillations,
- and.to construct the detailed models of the reactor core and systems appropriate for.these studies. ;
Even though existing analyses are preliminary and may contain large uncertainties, we have developed several insights based on these analyses. Large amplitude core power oscillations, with power peaks between 500 and 2000 percent of rated power, have been calculated for a LaSalle-like transient, if a scram does not occur. These large amplitude oscillations contribute to an average thermal power increase of 1.5 to 2.0 percent per '
100 percent of peak core power. That is, for example, a 500 percent peak power oscillation could lead to an increase of 7.5 to 10.0 percent in average thermal power in the core.
While previous ATWS stu :es assumed that oscillations occurred, i the contribution to average thermal power increase was not accounted for. Staff studies which account for the thermal 4
power increase are underway to determine its impact on previous ATWS analyses. In addition, studies of ATWS scenarios which do not result in Main Steam Isolation Yalve (MSIV) closure are '
being performed to determine whether modifications to operating procedures are needed. Operator actions under consideration include injecting boron earlier, reducing feedwater flow, and performing cther measures to reduce core inlet subcooling. The effect of these actions on avoiding or damping oscillations and reducing heat load to the suppression pool are being specifically [
examined.
In recent meetings between BWROG and the staff, BWROG indicated that they are evaluating the need for revised operator actions i
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' The Connissioners for situations involving an ATWS with oscillations. They are now emphasizing an engineering approach to evaluate appropriate -
operator actions to minimize the vulnerability to very large power oscillations within the Emergency Procedure Guidelines
.(EPG) philosophy. A limited analytical effort to confirm the modified EPGs would be performed. The analysis will address. '
the effect of the rise in thermal power caused by large '
oscillations. BWR06 will provide a closure plan based on this approach. The BWROG staff believes that this engineering ap-proach will close.the ATWS issue in this calendar year, whereas ,
emphasis on the analytical approach could leave this issue ;
unresolved for a long time and would be very taxing on. staff l and industry resources.
The staff expects to complete its analytical studies of the.
ATWS issue by the end of September. BWROG has indicated a '
similar objective with the closure plan being developed.
Various options for automatic and procedural response to ATWS events are an important point of these studies. Therefore, ,
the staff will not reach a final conclusion on the Petition to reopen rulemaking regarding ATWS until these studies are i complete.
We will continue to keep the Connis'sion informed on this matter.
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- t. cutive D rector l for Operations l C
DISTRIBUTIO!h Commissioners OGC OIG LSS GPA REGIONAL OFFICES EDO ACRS ACNW ASLBP l ASLAP l SECY.
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Inclosure 2 OMS Noa 3150 0011 NRCS 88 07 UNITED STATES NUCLEAR REGULATORY COMMI5510N 0FFICE OF NUCLEAR REACTOR RESULATION WASHINGTON D.C. 20555 June 15. 1988 WRC SULLETIN WD. 88-07: . POWER O5CILLATIONS IN 80! LING WATER REACTORS (SWRs)
' Addressees:
All holders of operating licenses or construction pemits for boiling water reactors (SWRs)
Purcose:
The purpose of_ this bulletin is to request that holders of operating licenses
- er construction pemits for boiling water reactors ensure that adequate operat-ing procedures and instrumentation are available and adequate operator training is provided to prevent the occurrence of uncontrolled power oscillations during all modes of SWR operation.
Descriotion of Circumstances:
On March g.1968, LaSalie Unit 2 underwent a dualfecirculation pump trip event. After the pump-trip, the unit experienced an excesbive neutron flux-estillation while it was on natural circulation. The event is described in
. NRC-Information Notice No. 88 3g, *LaSalle Unit' 2 Loss of Recirculation Pumps With Power Oscillation Event" dated June 15, 1988. Additional details of the event have been documented by the NRC augmented inspection team (AIT) in In.
Spection Report Nos. 50 373/88008 and 50-374/88008.
After investigation of the event by the licensee and further review by the NRC, the staff concluded that this event has significant generic safety implications because (1) past licensing calculations are not a reliable indicator that a core will .be stable under all operating conditions during a fuel cycle; (2) instrumen.
tation for detection and suppression of neutron flux escillations and recording instrumentation for evaluation of limit cycle flux escillations may not be ade-quatet (3) operating procedures and training may not be adequate to respond to this kind of transients (4) the magnitude and power peaking of the resultant neu-tron flux' oscillations may.be greater than previously experienced for in phase limit cycle oscillations during special stability tests and foreign operating reatter events: and (5) there is a question of coinpliance with General Design Criterion 17. ' Suppression of Reactor Power Oscillations.* 10 CFR Part 50. Ap-pendix A.
MMelS-C
- June 15,1988
- Pace 2 of 3 i
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Foreign reactor experience has indicated that there are conditions 4ther than ;
the natural circulation condition that existed during the LaSalle event, such as loss of feedwater heaters, which can lead to power oscillations. Further-more, the power oscillations may be asymetric and lead to high local neutron
- flux levels without detection and automatic scram. Therefore, powe,r estillations are of safety concern because they may result in fuel damage.
Some characteristics of the LaSalle neutron flux estillation have led to con-cerns about the' applicability of previous safety analysts. The magnitude of in phase limit cycle oscillations ereviously observed on the APRMs during special stability tests and operating reactor events were typically in the range of 55 to 155 (peak-to-peak) of rated power, and as high as 255. This compares to peak to-peak values of about 100% at the time of the 118% neutron
, flux trip for LaSalle. The implications, if any, on the bounds for neutron flux esci11ations considered in previcas safety analyses, including peak power ,
resulting from asymetric esci11ations and the effects of recirculation pump trip actions for ATWS events, require further study. The NRC will pursue these l
- issues with the BUR Owners Group in parallel with utilities taking the actions specified below.
Reevested Actions:
Operatinc Reactors:
- 1) Within 15 days of receipt of this bulletin, sil BWR licensees should ensure that any licensed reactor o>erator or Shift Technical Advisor performing shift duties has been tieroughly briefed regarding the Parch g.1988 LaSalle Unit ? event.
- 2) Within 60 days of receipt of this bulletin all BWR licensees should verify the adequacy of their procedures and operator training programs to ensure that all licensed operators and Shift Technical Advisors are cognizant of:
i a) those plant conditions which may result in the initiation of un.
controlled pewer esci11ations b) actions which can be taken to avoid plant conditions which may result in the initiation of uncontrolled power oscillations c) how to recognize the onset of uncontrolied power esci11ations, and d) actions which can be taken in response to uncontrolled power oscil-lations, including the need to scram the reactor if oscillations are not promptly terminated.
Addressees should also verify the adequacy of the instrumentation which is reliird upon by operators within their procedures.
It is expected that all BURS will have procedures and operator training programs l to address uncontrolled power esci11ations regardless of calculated decay ratios.
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- NRCB C3 07
- June 15,1988 Page 3 of 3 Construction Pemit Holders:
Prior to scheduled fuel load date, construction pemit holders should couplete actions 1 and 2, above.
Reportine'Reevirements:
Within 30 days of completion of the actions requested above, all holders of :
operating licenses and construction pemits shall confim by letter that the requested actions have been completed and implemented. Licensees and remit holders shall docu. ment and maintaip at the plant site for a period of at least two years an evaluation of the adequacy of their procedures, training programs and the instrumentation relied upon within their procedures.
The written reports required abo'<e shall be' addressed to the U. 5. Nuclear Regulatory Comission. ATTN: Document Control Desk, Washington, D.C. 20555, under oath or affimation under the provisions of Section 182a Atomic Energy Act of 1954, as amended. In addition, a copy shall be submitted to the appro.
. priate Regional Administrator.
This requirement for infomation yas approved by the Office of Management and Budget under blanket clearance number 3150 0011. Coments on burden and dupli-cation should be directed to the Office of Management and Budget. Reports Management Room 3208, New Executive Office Building, Washington, D.C. 20503.
If'you have aey cuestions about this matter, please contact one of the technical contacts listed below or the Regional Administrator of the appropriate regional office.
1 Charles E. Rossi, Director Division of Operational Events Assessment Office of Nuclear Reactor Regulation Technical Contacts: L. phillips, NRR (301)49?.3235 P. C. Wen, NRR (301) 492-1172
Attachment:
List of Recently Issued NRC Bulletins O e m-* -
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Enclosure 3 OMB No.: 3150 0011 NRCB 88-07, Supplement 1 i UNITED STATES ,
NUCLEAR REGULATORY COMMIS$10N OFFICE OF NUCLEAR REACTOR REGULATION WASHINGTON, D.C. 20555 December 30, 1988 NRC BULLETIN NO. 88-07, SUPPLEMENT 1: POWER OSCILLATION $ IN B0! LING WATER REACTORS (BWRs) .
Addressees: .
All holders of operating licenses (OLs) or construction permits (cps) for boiling water reactors (BWRs).
t
Purpose:
I The purpose of this supplement is (1) to provide additional .infomation con-l cerning power oscillations in BWRs and (2) to request that addressees take action to ensure that the safety limit for the plant minimum critical power ratio (MCPR) is not violated.
Description of Circumstances:
Licensees were requested in NRC Bulletin No. 88-07 to take actions to prevent ;
the cecurrence of uncontrolled power oscillations during all modes of BWR operation. In addition, as mentioned in the bulletin, the NRC, as a separate action,requestedthattheBWROwnersGroup-(BWROG)performgenericevaluations l
of the BWR plant response to core themal hydraulic instabilities. The prelim --
inary results of these evaluations and the NRC's ongoing independent study-indicate that when regional power oscillations become detectable on the average power range monitors (APRMs), the MCPR safety margin may be insufficient under L some operating conditions to ensure that manuel actions taken in response to APRM signals cuid prevent violation of the MCPR safety limit. In-addition, designfeaturesofmanyreactorprotectionsystems(e.g.,filteredAPRMsignals to previde a simulated Themel Power Monitor in the power / flow scram circuit) render them ineffective for automatic scram protection during regional thermal hydraulic instabilities.
In November 1988,' General Electric. Company (GE) issued a letter entitled
" Interim Recomendations for Stability Actions" to the BWR licensees. The.
interim corrective actions recomended by GE were reviewed by the NRC and have been found acceptable for those plants which have effective automatic scram protection for regional oscillations. For plants which do not have effective
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, NRCB 88-07, Supplement 1 ;
December 30, 1988 Page 2 of 4 automatic scram (such as flow biased scram) protection for regional oscilla-tions, the staff believes that the procedu'res recomended by GE and adopted by l the BWROG may not provide sufficient, reliable protection. Therefore, the !
staff is requesting that plants without effective automatic scram protection for regional oscillations manually trip the reactor in response to every situation in which two recirculation pumps are tripped with the reactor in the RUN mode. In addition, the BWROG recomendations were addressed to GE-fueled reactors. The staff is addressing the applicability of these recomendations to reactors with fuel supplied by other vendors and for new fuel designs which have not been previously approved. The BWROG recomendations and provisions of this supplement are not applicable to Big Rock Point (Docket No. 50-155) because of unique design features involving a lack of flow control capability, and because existing operating limitations enforced by technical specifications address the stability concerns which are the subject of this supplement.
l The NRC is currently working with the BWROG to develop a generic approach to
! long-tem corrective actions. The BWROG is planning to evaluate hardware l modifications and/or additions and complementary procedure revisions needed to facilitate stability monitoring and to improve the manual and/or automatic
, protective actions as needed to avoid neutron flux esc 111ations and to suppress them if they occur. The BWROG study is expected to be completed within 6 months of the issuance of this supplement and to result in generic recomenda-tions. The BWROG has indicated that these recomendations will be transmitted to addressees in parallel with the NRC review in order to facilitate develop-1
' ment of plant-specific solutions within 12 months.l The staff expects to issue another generic communication that will provide guidance for long-tem resolu-tion of the stability issue.
Actions Recuested:
Operating Reactors:
(1) Within 30 days of receipt of this supplement. F alWR licensees should implement the GE interim stability recomendW.ons described in Attach-ment 1. However, for those plants that do not have effective automatic scram protection in the event of regional oscillations, a manual scram should be initiated under all operating conditions when two recireviation 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-mendations (Attachment 1) were derived for those BWRm using NRC approved l GE fuel. For BWRs using fuel suoplied by other vendors, these regions should be adopted in principle, but the power / flow boundaries should be based on existing boundaries that have been previously approved by the NRC. For proposed new fuel designs, the stability boundaries should be reevaluated and justified based on any applicable operating experience.
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NRC8 88-07, Supplement ! 1 December 30, 1988 Page 3 of 4 calculated changes in core decay ratio using NRC approved methodology, and/or core decay ratio measurements. There should be a high degree of assurance that instabilities will not occur under any circumstances of operation in Region C.
(3) The BWROG recommendations of Attachment 1 are ambiguous with respect to pemissible conditions for entry of Regions 8 and C. Although the recom-mandations state that intentional operation in Region 8 is not pemitted and operation in Region C is permitted caly for purposes of fuel condi-tioning during rod withdrawal startup operations, intentional entry into l
-Region 8 or C is also allowable in si tuat ions wh ere rod insertion or a flow increase is required by procedures to exit Regions A and 8 after un-intentional entry. Licensees should ensure that the procedures and training employed for implementation of these recomendations avoid any similar ambiguity which could lead to operator confusion.
Construction Permit Holders:
All construction pemit holders should complete the requested actions above before the date scheduled for fuel loading. .
Reporting Requirements:
Within 60 dsys' of receipt of this supplement, pursuant to 10 CFR 50.54(f), all holders of OLs shall advise the NRC by letter whether the requested actions have beer completed and implemented. Prior to fuel loading, CP holders shall advise t;te NRC by letter that the requested actions have been completed and
-implemelted. The staff will evaluate these resporises to detemine whether any additional action by the staff is necessary.
The requwed written reports shall be addressed to the U.S. Nuclear Regulatery Comission, ATTN: Document Control Desk Washington, D.C., 20555, under oath j 4
or affimation under the provisions of Section 182a Atomic Energy Act of 1954, as amended. In addition, a copy of the report shall be submitted to the appropriate . Regional Mininistrator.
This request is covered by Office of Management and Budget Clearance Number 3150-0011 which expires December 31, 1989. The estimated average burden hours is approximately 100 to.200 person-hours per . response, including assessment of the new recomendations, searching data sources, gathering and analyzing the-data, and preparing the required reports. These estimated average burden hours pertain only to these identified response-related matters. Corments on the accuracy of this estimate and suggestions to reduce the burden may be directed to the Office of Management and Budget. Room 3209 New Executive Office Build- ,
e ing Washington, D.C. 20503, and to the U.S. Nuclear Regulatory Comission, l 1
Records and Reports Management Branch. Office of Administration and Resource Management. Washington, D.C. 20555.
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- NRCS 88-07, Supplement 1 December 30, 1988 ,
Page 4 of 4 !
If you.have any questions about this matter, please contact one of the techni-cal contacts listed below or the Regional Administrator of the appropriate !
l regional office. l
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I 4 Charles E. Rossi DirectoY Division of Operational Events Assessment Office of Nuclear Reactor Regulation Technical Contacts: L. Phillips, NRR (301)492-3235 i P. C. Wen, NRR (301)492-1172 Attachments:
- 1. *1nterim Recomendations for Stability Actions " GE, November 1988.
L 2. List of Recently Issued NRC Bulletins 1
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' NRCB 88-07. Supplement 1 Attachment 1 December 30, 1983 Page 1 of 4 ,
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' ~ To: 3WR 9ti11 ties Subjoet INTERIM RECOMMENDATIONS FOR STABILITV ACTIONS r
, 82, working with the SWR Owners' group, is pertemine e generle evalue.
The objective i tica et plant response to stability related escillatlens.
- as to determine the degree of sitigation provided by the outstine l reacter protection systen and to determine the sargin to safety limits- :
cssesisted with possible automatie or manual estions. preliminary results indicate that for eartain plants and operatine senditions,
.interia operating procedures supplement 'i ng these prevIously provided in 31L-aso are appropriate to assure adeguate.sarein to the Minisua Critical power Ratie (MCpR) safety limit should regional estillations i coeur. -while these results are preliminar '
which should receive immediate attentlen. y, they indicate a sendition
' Aesordingly, the recommended 'Interia stability corrective Actions for SWRs Using 82 Fuel
- sentained in the enclosure are provided for imple.
Centation on your plant (s). Ongoing analysis will better defane the
.destes of senservatisa in this approach. Newever, given trosy's ,
understanding of the situation, lt is prudent to immediately implement
- these resensenda-tions en an interia basis. 4
-We believe that the attached reconnendations w!11 help 49 prevent
~ instability and provide clear and seneise guidelines for operator action i to keep plant operation within acceptable beands in the unlikely event of regional oscillations. Furthe n ere, by taking decisive estion to ,
cvoid the region in which low stability sargino exist, post event
.opeoulation regarding possible safety limit violetions saa be avoided. ;
(original signed by)
P. W. Marriett, Manager Lisensing and consulting servlees l
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2NTER3M CORRICTIVE ACTIONS
- 2. Intentional operation shall mot be allowed in Region A er Region 9 et Figure 1.
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- 3. If Region A is unintentionally entered:
- L Oreup 1 plant operators shall take insediate actions to exit the region. Insediate action sensists of either l
Insertion of a predefined set of sentrol rods which will most effectively reduce sore thermal power. i er -
l Increasing recirculation pump speed if one or more pueps are in operation. starting a recirculation to exit this region is NOT an appropriate action. pump -
Group a plant operators shall annually serta the reactor to exit the region.
- 3. If Region 3 is unintentionally entered:
Group 1 and Group 2 plant operators shall take samediate action to exit the region. Emnediate action sensists of ,
Insertion of a predefined set of control rods which )
l will sost effectively reduce sore thermal pbwer. l
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er i Increasing recirculation pump speed or recirculation !
flow (FCV if one er more pumps are in L operation. plants)ing Start a recirculation pump or shifting l from low to high speed (FCV plants) to exit this region 4
is NOT an appropriate action. l
- 4. Intentional operation in Region C shall be allowed only l for control red withdrawals during startup requiring E
PC10MR. This region should be avoided for sentrol red seguence exchanges,. surveillance testing and reacter shutdowns.
L During control red withdrawal, flux monitoring l ahould be conducted in accordance with SIL 380, o
Revision 1.
- 3. If at any time durins operation in Region A,3 or C, sore thessal hydraulle instability occurs, the plant operator shall manually scraa the reactor.
. Evidence of thermal hydraulic ' instability consists of l ApAM peak to peak escillations of greater than 104 er l periodic LPM upscale or downscale alarms in addition to the guidance provided in SIL 380, Revision 1.
_.- _ _---- _ _ -- _ _ _ - _ _ + - - ~ - . _,---..,,--~--.,--.,,--n..
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CORE F2W 3288 EttAN 40% OF RATED CORE FMlW REGION-S REACTOR POWER SEWEEN THE 80% AND 100% ROD LINES i 00RE FMMt MSS tilAN 404 0F RATED CORE RATED l
REGION O REACTOR POWER SREATER StLAN TNE 804 ROD LINE .
- CORE F2R SENEDI 40% AND 454 0F RATED CORE FIDW r
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- Page 4 of 4
. TABLE 1 WS OPERATING REACTOR,Q* -
SROUP 1 -
OYSTER cREER MINE MILE 1 DRESDEN 3,3 M!LIATONE 1 CUAD c272Es 1,3 P214 RIM MONTECELLO DUANE ARN01D C00PER-VEMONT YANKEE-PEACH BOTE9M 3,3-LIMERICK SROUP 3 BRUNSWICK 1,3
- MATCH 1,3 '
i SROWHS FERRY 1,3,3 '
l FEuz 3 I FIT 2 PATRICK l McPE CREEK I
,- SUSQUEHANNA 1,3 l h LAS AL12 1,3 RANr0RD &
SHOREHAM '
MINE MILE PT 3 cLINTON t PERRY
' RIVER SEND .*
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. . . NUCLEAR REGULATORY COMMISSION U1206000007001, D. C. BOOM
~ \,***** EDO' Principal Correspondence Contro! ,
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DUE: EDO CONTROL: 0004159 i LFROMi - ,, / 2Jf$'9 DOC'DTs 12/17/88 l FINAL REPLY:
THOMAS V. CHEMA DHIO.PUBLIC UTILITIES.CCAMISSION i
TO:
- CHAIRMAN ZECH FOR SIGNATURE OF: 8* GRN ** -CRC NO:-88-1255
(
DESC: ROUTING:
FINAL' CONSULTANT REPORT TO OHIO PUBLIC UTILITIES STELLO iCOMMISSION ON GE REED REPORT TAYLOR '
BLAHA DATE: 12/29/88 JORDAN, AEOD BECKJORD, RES I it CONTACT: DAVIS, RIII l ASS!CNED TO: MURRAY, DGC
- . NRR ,
MURLEY .
l 'CFECIAL' INSTRUCTIONS OR REMARKS:
j:FOR APPRDPRIATE ACTION. IF REPLY IS PREPARED, IT CHOULD BE FOR THE CHAIRMAN'S SIGNATURE. [
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10GGING DATE Dec 22 88 PAPER NUMBER: CRC-88-1255 ACTION OFFICE EDO AUTHOR: T.V. Chena -
AFFILIATION OH (OHIO)
LETTER DATE: Dec 16 88 FILE CODE:
SUIL7ECT:
Final report to the Public Utilities Commission of
' Ohio review of the GE Reed Report ACTION: Appropriate
. DISTRIBUTION: Cars, OGC, Secy SPECIAL MANDLINGt None NOTES:
Please Inform Secy of Action...If a response is Dan
- necessary, please prepare for ChaiSignature....perChairman's
- DATE DUE:
DATE SIGNED:
SIGNATUREt .
AFFILIATION .
(tee'd Oft. ED0 Date _ j p - a t - W y M .'s D # -
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o STATE OF OHIO PUBLIC UTILITIES COMMISSION 180 EAST BROAD STREET COLUMBUS, OHIO 43266-0573 4'"$$$ifoli"
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I. December 17, 1988
, -Lando W. Zech Jr.
' Chairman U.S. Nuclear Regulatory Commission 11555 Rockville Pike Rockville, Maryland 20852 Dear Chairman tech L, _As you know, the.PUCO retained consultants in May of 1988 to review the " Reed Report" to determine whether or not the 1975 '
G.E. internal study contained any information that posed safety consequences for the Petry Nuclear Power Plant. l On December 16, 1988, we released the study, performed by the Ohio ,
State University Nuclear Engineering Program with consultants MHB Technical.. Consultants, San Jose, California and Nuclear Education and Training Services, Inc., Columbus, Ohio. The study
- concludes that the Reed Report issues that are relevant to safety ;
at the Perry plant are " closed". ,
The consultants recommend,-however, that the PUC0 monitor regulatory developments originating from the March 1988 LaSalle
" transient event". They also recommend that we watch the development of materials research technology, particularly stress ,
corrosion cracking and embrittlement phenomena. ,
The principal investigator from the Ohio State Nuclear Engineering
. program will make a formal presentation to.the Ohio Public .
Utilities Commission in January. I am enclosing a copy of the Executive Summary and the Body of the Report for your review.
If you have any questions, I would be delighted to hear from you.
cerely Cha Thomas' ?. Chema Chairman PUCO
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FINAL REPORT
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THE PUBLTC UTILITIES COMMISSION OF OHIO ,
THE OSU REVIEW OF THE
- REED REPORT" December 15, 1988 i
by ,
DR. R.N. CHRISTENSEN AND DR. D.W. MILLER .
NUCLEAR ENGINEERING PROGRAM i THE MECHANICAL ENGINEERING DEPARTNENT THE OHIO STATE UNIVERSITY L
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i Mr. Thomas V. Chema Chairman Public Utilities to ission State of Ohio 280 East Broad Street Colus6us, Ohio 43266 05 ;
Dear Mr. Chema:
Thank you for your consu (ants' review of the " Reed Report" as it relates to Perry Nuclear Power Plant. I have provided the report to the staff for information and requested they keep you advised of issues as they develop regardingtheLaSalletransienteveht.
Sincerely,
\
'\
Lando W. Zech, Jr. '
Distribution: '
Docket Flies EJordan Jhurray \ OGC PKreutzer ED004158 EBeckjord Local PDR i CKammerer RLickus DCrutchfield ABDavis TMurley/JSniezek VStello MVirgilio NRC POR GHolahan JHannon SECY EDO r/f GPA/PA GPA/SP TColburn PDIII.3 r/f DNossburg SDroggitus
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- Chairman Public Utilities Commission
.m l State of Chio .
180 Columbus, East Srcad chio Street 43266-0573 :
I
Dear Mr. Chema:
pared by the Chuanc ether consu t" for the safety of Thank you for sharing We with have us thethereport forwarded report preStat tod they will on.the implications of the 1985 " Reed Repor the Perry Nuclear Power Plant.
I our technical staff for its consideration, t it. taff an -In addition..we to keep your are tacting you if they have questionsregarding developments abouinstructingtheh you i
e
' . office advised of'any regulatory ,
'LaSalle transient event, about whic Sincerely, w, s,
,J.
Lando W. Ze jp r 1
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to Ohio Public Utilities Commission re GE Reed Report 1
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Mr. Thomas V. Chema DISTRIBUTION:
Chairman Docket Files NRC & Local PDR E00#04158 Public Utilities Commission EDO R/f SECY TMurley/FMiraglia State of Ohio JPartlow DCrutchfield / WRussell 180 East Broad Street GHolahan SVarga / JZwolinski Columbus, Ohio 43266-0573 JHannon MDLynch / TColburn i PKreutzer LPhilli HRichings !
Dear Mr. Chema:
AThadani OGC-WF1/ps/ BWR PMs ABDavis WITS F,41e SNewberry l 1 am responding to the concern in your letter of Dece er 17, 1988 regarding !
the power oscillation transient of March 1988 at the aSalle County Nuclear Station, Unit 2. We committed to keep you informed n this matter in our prior letter to you dated January 14, 1989.
/
sfaffhasrecentlydetermined The U. S.are that there Nuclear Regulatory acceptable long-termCommission resolutio (NRC)gs for this particular issue and sunnarized its position on the generic implications of the power tran-sient event at the LaSalle plant in SECY 90'152 (Enclosure 1). The implementation of the long-term resolution'of this issue as described in SECY90-152willfurtherenhancethesafetyoftheboilingwaterreactors (BWRs) including the Perry Nuclear Power Plant. The BWRs have continued to operate safely during the interim byfollowing the NRC requirements in Bulletin 88-07 and its supplement istued in June 1988 and December 1988, respectively (Enclosures 2 and 3) /
In this regard, we have found t$ the present NRC regulation (10 CFR 50.62) regarding an Anticipated Transtent Without Scram (the ATWS Rule) is still applicable for BWRs. Thestpffcontinuestoevaluateoperatingreactor events to ascertain that the fundamental concepts embodied in the ATWS Rule are valid. Should addition'al enhancements be required, they will be imposed as appropriate.
The above described measures for the operating BWRs and additional long-term activities described dn the enclosures constitute our final resolution of this issue. Accordingly jthis completes our commitment to keep you informed.
Sincerely, James M. Taylor Executive Director '
for Operations Enclosyres:
As stated EVIOUS CONCURRENCE iFC
/
- cLA:/PDill-3: PM -
- NRR/DRSP :
D/PD()I'l-3:*TECHED :*AD/DRSP T
AME : Ppeutzer : MDLynch : LPhillips: J a non : JMain : JZwolinski IATE : 05/29/90 : CG/0G/f 0 : 05/21/90 : / / : 05/30/90 : 05/23/90
'FF :D :D/NRR :EDO
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ATE :l//(0/90 : / /90 : / /90 : / /90 : / /90 0FFICIAL RECORD COPY l Document Name: WITS 8900031
.I O
Mr. Thomas V. Chema DISTRIBUTION:
Chairman Docket Files NRC & Local PDR ED0#04158 Public Utilities Commission EDO R/f SECY TMurley/FMiraglia i State of Ohio JPartlow DCrutchfield WRussell ,
180 East Broad Street GHolahan SVarga JZwolinski Columbus, Ohio 43266-0573 JHannon MDLynch TColburn PKreutzer LPhillips HRighings
Dear Mr. Chema:
AThadani OGC-WF1 BWR PMs ABDavis WITS File ewberry I am responding to the concern in your letter of December 17, 1988 /egarding the power oscillation transient of March 1988 at the LaSalle Countf Nuclear
-Station, Unit 2. We committed to keep you informed on this mat r in our prior letter to you dated January 14, 1989.
The U. S.-Nuclear Regulatory Commission (PRC) staff has rep 4ntly determined that there are acceptable long-term resolutions for this parti ular issue and summarized its position on the generic implications of e power transient event at the LaSalle plant in SECY 90-152 (Enclosure . The implementation of the long-term resolution of this issue as descri in SECY 90-152 will ,
further enhance the safety of the boiling water re tors (BWRs) including i the Perry Nuclear Power Plant. The BWRs have co inued to operate safely i during the interim by following the NRC require nts in Bulletin 88-07 and its supplement issued in June 1988 and Decemby 1988, respectively. (Enclosures 2 and 3). j-Inthisregard,wehavefound.thattheprefientNRCregulation(10CFR50.62) regarding an Anticipated Transient Without Scram (the ATWS Rule) is still applicable tor BWRs. The staff continues to evaluate operating reactor events te ascertain that the fundamental concepts embodied in the I.TWS Rule j are valid. Should additional enhancements be required, they will be L imposed as appropriate.
l .
l 1 trust that you find the enclosed infonnation useful and would be pleased ,
to respond to any further questions you may have.
/ Sincerely, 7
/
/
James M. Taylor Executive Director for Operations
Enclosures:
As stated DOCUMENTNAMEgWITS 8900031
- SEE PREVIOUS CONCURRENCE d Offlce: LA/PDIII-3 M/PDill NRR/DRSB PD/Ptf111-3 TECH ED Surname: *PKreutzer MDLynJh *LPhillips J)1annon *JMain Date: 05/29/90 odp4!90 05/21/90 y/ 4/90 05/30/90 Office: AD/DRSP (A)D/DRSP ADP/NRR DD/NRR D/NRR EDO Surname: *JZwolinski GHolahan JPartlow FMiraglia TMurley JTaylor Date: 05/23/90 / /90 / /90 / /90 / /90 / /90
9-Mr. Thomas V. Chema 2 of tion Ill. We anticipate that we will complete our review of the gene c.long-term resolution of stability operational requirements by the end o 990.' To close this issue, the NRC will require each BWR licensee to submit r review by the NRC staff, a plant-specific justification for the particul option chosen.
One unresol ed aspect of this issue is the effect of power oscillations that can occur du ing those plant transient events that involve an Anticipated TransientWitoutScram(ATWS). The results of the analytical effort to date indicate hat large amplitude oscillations that occur during ATWS events could in rease the average thermal power in the reactor core. This potential increate in reactor power during an ATWS event was not considered ir, the developmen' of the ATWS Rule (10 CFR 50.62). ,
While the sffect of tential power oscillations on the ATWS Rule is still unresolved, both the R0G and the NRC staff have preliminarily determined that an engineering app ach (for example, injecting a soluble boron solution into the reactor core ear ier than presently provided for in existing emergency procedures) is a ractical solution to this phenomenon. It the NRC staff concludes that one' r more engineering approaches are required, this could be accomplished b odifying the existing generic Emergency Procedur(. Guidelines (EPGs)ytha licensees use in developing plant-specific Emergency Operating Procedures ( Ps). We will consider all these factors in determining whether to raconsi r the ATWS Rule.
I trust you will find this status repo useful and I will' continue to keep your office informed of significant eme ing issues.
Sincere ,
James M. Ta lor.
Executive Di ctor for Operati s
Enclosures:
?
As stated DISTRIBUTION L
Docket File GHolahan 0GC NRC & Local PDR 50-440 SVarga BWR PMs EDO #04158 JZwolinski PDs ED0 Reading JHannon ABDavis
! SECY MDLynch OMossburg, WITS 00031 L TMurley TColburn WITS File l FMiraglia PKreutzer SNewberry
- 'JPartlow LPhillips [ WITS 8900031]
DCrutchfield HRichings WRussell AThadani
- SEE P E ONCURRENCE
'ED131).A :- *NRR:SRXB IPD33:D TECH:ED *AD: RSP3 -
PWdtzer MDLynch/bj LPhillips JHannon 7% Q4JZwolineH 5/2p/90 O$~/ff90 05/21/90 / /90 5/30/90 05/23/90 (A)D:DRSP ADP:NRR DD:NRR D:NRR EDO GHolahan- JPartlow FMiraglia TMurley JTaylor
/ /90 / /90 / /90 / /90 / /90
_ e _- _ . _ _ . . _ _ _ _ _ . . . . . . . . .
9- ,
- a +.
_ Mr. Thomas V. Chema DISTRIBUTION:
. Chairman \: Doctet Files NRC & Local PDR ED0#04158
- Public Util) ties Commission'
- ED0 R/f SECY TMurley/FMireglia-State of Oh- JPartlow DCrutchfield WRussell 180 East Bro d Street GHolahan SVarga JZwolinski Columbus, Ohi 43266-0573 JHannon MDLynch TColburn PKreutzer LPhillips HRichings
Dear Mr. Chema:
AThadani OGC-WF1 BWR PMs ABDavis WITS File SNewberry
} -
I am responding to the concern in your letter of Decenter 17, 1988 regarding the power oscillat n transient of March 1988 at the LaSalle County Nuclear Station, Unit 2. W committed to keep you informed on this-matter in our
< -prior letter to you ted January 14, 1989.
[ The U. S. Nuclear Regu tory Commission (NRC) staff has recently determined that
-there are acceptable lo -term resolutions for this particular issue and o sunnarized its position. the generic implications of the power transient event at the LaSalle plan in SECY 90-152 (Enclosure 1). The implementation
[
of the long-term resolutio of this issue as described in SECY 90-152 will further enhance the safety theboilingwaterreactors(BWRs) including the Perry Nuclear Power Plan The BWRs have continued to operate safely
-- during the interim by followi the NRC requirements in Bulletin 88-07 and its sup lement issued-in June 1 88 and December 1988, respectively. (Enclosures-
[ 2 and 3 ..
In this regard,~we have found that the present NRC regulation (10 CFR 50.62)
=
'regarding.an Anticipated Transient thoutScram-(theATWSRule)is=still require additional enhancements for applicable for BWRs. We may, howeve the ATWS event as a practical resoluti n for any affect the potential for power transients might have on the ATWS ule.
I trust that you find the enclosed inform ion useful-and woulc be pleased to respond.to any further questions you ma have.
Sincerely,
- ' James M. Taylor Executive Directo for Operations
Enclosures:
As stated i.
DOCUMENT NAME: WITS 8900031
- SEE PREVIOUS CONCURRENC Office:' LA/PDIII-3 Dill
Sename: *PKreutzer MDLynch LPhillips @an n JMain Date: 05/29/ / e6/3/ /90 05/21/90 ) /J 90 05/30/90 Office: AD/DRS (A)D/DRSP ADP/NRR DD/N R D/NRR EDO g Surname: *JZwoli i GHolahan JPartlow FMiraglia TMurley JTaylor g Date: 05/23/90 / /90 / /90 / /90 / /90 / /90 w
. - - - . . . ......-m.~
Mr. Thomas V. Chema 2 anticipate that our review of the generic long-term resolution of stability operational requirements will be complcted by the end of this year. To close this issue, each BWR licensee will be required to subn.it a plant-specific justification for the particular option chosen which in turn will be reviewed by the NRC staff.
One aspect of this issue which has not yet been resched is the effect of power oscillations that can occur in those pitnt transient events which involve an Anticipated Transient Without Scram (ATWS). Basically, the analyticel effort to date indicates that large emplitude oscillations in ATWS events could increase the average thcrmal power in the reactor core. This potential increase in reactor power durin>g an ATWS event was not considered in the developa nt of the ATWS Pule (10 CFR 50.6?).
While the impact of potential power oscillations on the ATWS Rule is still unresolved, both the BWROG and the NRC staf f have preliminarily determined p
that an engineering approach (e.g., injecting a soluble boron solution into the reactor core earlier than presently provided for in oisting en.ergency prccedures) is a practical solutien to this phenca.enon. If the NRC stoff concludes that one or a number of engineering approaches are rpqtiired, this could be accomplished by modifying the e)isting generic Emerg(ncy Procedure Guidelines (EPGs) which are utilized by licensees in devel ing plant-specific Imergency Operating Procedures (E0Ps). All these factor will be includeo in our determination as to whether the ATWS Rule shoul be reconsidered.
I trust you will find this status report useful an will continue to keep your office informed of significant emerging issu .
Sincerely, James M f! Taylor Execu34vcDirector for Operations
Enclosures:
/
As stated DIhTRIBUTION Docket File CFolaha OGC NRC & Local PDP 50 440 SVargy BWR PMs E00 #04158 JZwpinski PDs ED0 Reading JH nnon ABDavis SECY Lynch DMossburg, WITS 6900031 TMurley 1Colburn WITS File FMiraglia PKreutzer SNewberry JPartlow LPhillips DCrutchfield HRichings WRussell AThadani SEE P VIOUS CONCURRENCE
- PD33LLA PD33:PMo. y , NRR:SRXB PD33:0$// TECH:ED AD:DRSP3 Prebtttzer MDLyncb'/b . t LPhillips
- JHannofW JZwolinski U /;p /90 5/u/90 / /90 r /23/90 / /90 f/0/90 (A)D:DR P ADP:NRR DD:NRR D:NRR EDO GHolahan JPartlow FMiraglia TMurley JTaylor
/ /90 / /90 / /90 / /90 / /90 DOCUMENT NAME: WITS 8900031
~
~-
. e t .'
A Mr. Thomas V. Chema 2
)
anticipate that our re' view of the generic long-term resolution of stability o>erational requirements will be completed by the end of this year.^ To close tais issue, each'BWR licensee will be required to submit a' plant . specific ,
justification for:the particular option chosen which in turn wi 'l be reviewed by the NRC staff.
-One aspect of this issue which has not yet been resolved is he effect of power oscillations that-can occur in those plant transient event which involve an '
AnticipatedTransient-WithoutScram(ATWS). Basically, th'e analytical effort
. to date indicates'that large amplitude oscillations in ATWS events could increase the average thermal power in the reactor core / This potential increase in reactor power during an ATWS event was not considered in the -
developmentof.theATWSRule(10CFR50.62).
/
-Whiletheimpactofpotentialpoweroscillations[ntheATWSRuleisstill unresolved,boththeBWROGandtheNRCstaffbedevesthatanengineering approach (e.g., injecting a soluble boron solution into the reactor core earlier than presently provided for in existi/g emergency proceduru) is a practical solution'to this phenomenon. If the NRC staff concludes that one or a number of engineering approaches are r4 quired, this could be accom-E p(EPGs) which are f.ranslated by licensees /into plant-specific Emergency 11sh Operating Procedures (EOPs). All thes ' factors will be included in our determination as to whether the A7WS e should be reconsidered.
If you have an Manager (LPM) y questions for this hsue, M. Di onLynch, theseat m6tters, please contact the Lead Project (301) 492-3023.
Sincerely, James M. Taylor Executive Director t
- for Operations
Enclosures:
/
l:, :As stated /
DISTRIBUTION ,
L Docket File / GHolahan 0GC f
NRC.& Local PDR 50-4,40 SVarga BWR PMs j EDO #04158~ JZwolinski PDs l E00 Reading JHannon ABDavis SECY . MDLynch DMossburg, WITS 8900031 TMurley 1 y TColburn WITS File FMiraglia / PKreutzer SNewberry l s JPartlow > LPhillips L DCrutchfie/d - HRichings WRussel ,
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- l. N o-f (ft ,'j DISTRIBUTION (CONT'D) i
!@ .j PLANT DOCKET NO.
'rif" : Browns Ferry l' Browns Ferry 2 50-259 50-260 Browns Ferry 3: 50-296
%- m Brunswick 1- 50-325 i W Brunswick 2. .50-324 Clinton. 50-461 Li? Cooper 50-298 Dresden 2 50-237 Dresden 3. 50-249
~ Duane Arnold 50-331 1 Fermi.2- 50-341-Fitzpatrick 50-333 i l Grand Gulf 1 50-416 Grand Gulf 2 50-417.
Hatch 1 50 321 Hatch 2- _
50-366 Hope Creek 50-354 <
LaSalle 1- 50-373
'LaSalle'2 50-374 Limerick 1. 50-352 Limerick 2 50-353 Millstone 1 '50-245 Monticello . , 50-263 Nine Mile Point 1 50-220
- Nine Mile Point 2 410> .
Oyster Creeki 50-219-- -I Peach Bottom 2 50-277
~ Peach Bottom 3 50-278 Perry 1 50-440 r
' Pilgrim- _ 50-293
-Quad Cities 1 50-254 Quad Cities 2 50-265 i River / Bend 50-458 ..
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