ML20096D602
| ML20096D602 | |
| Person / Time | |
|---|---|
| Site: | Cooper  |
| Issue date: | 05/04/1992 |
| From: | Horn G NEBRASKA PUBLIC POWER DISTRICT |
| To: | |
| Shared Package | |
| ML20096D605 | List: |
| References | |
| NSD920302, NUDOCS 9205180145 | |
| Download: ML20096D602 (10) | |
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m NSD920302 May 4, 1992 U.S. Nuclear Regulatory Coranins ton Attention: Document Control Desk Washington, D.C.
20555 Gentlemen:
Subject:
Proposed Change No. 100 to Technical Specifications Elicination of Main Steam Line Radiation Monitor Scram and leolation Functions Cooper 1;uclear Statton NRC Socket No. 50-298, DPR-46 In accordance with tne applicable provisions speci fied in 10 CFR 50, the Nebraska Public Power District (District) requests that tne Cc,oper Nuclear Stat.lon (CNS) Technical Specificationr be revised as specified in the attachmcce The proposed changes remove the oot rabil! ty requirernents, action statements, and associated surveillance requirements for the Main Steam Line Radiation Monitor (MS1JOI) scram and Group 1 Contaimnent Isolation functions.
Removal of these MSLRM fun tions have been determi.,ed to be accepte.ble by the NRC Staff based on their review of NEDO-31400, " Safety Evaluation for Eliminating the Boiling Water Recetor Main Steam Line Isolation Valve C?osure Function and Scram Function of the Main Steam Line Radiation Moaltor."
The District has determined that the analysis described in NEDO-31400 conservatively bounds the CNS accident analysis, and therefore is applicable.
The District will mordinate with the CNS NRC Project Manager implementation of the corresponding plant design change te ensure it coincides with approval of this license amendment.
Accordingly, the a ttached contair.s a uescription of the proposed change, the attendant 10 CFR 50.92 evaluation, and the CNS Technical Specification pages revised by the inst;tution of this change.
This oroposed change has been reviewed by the necessary Safety Review Comittee, and incorporatas all mendnwnts to the CNS Facility Oper ating Licenr e through Amendment 152 issur.
M?.rch 11 1992.
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S. Nuclear Regulatory Commiasion Page 2 of 3 May 4, 1992 By copy of this lecter and attachment, the appropriate State of Nebraska official is being notified in accordance with 10 CFR 50.91(h)(1). Copies to the NRC Region IV Office and the CNS Resident Inspector are also being aent 4.n accordance with 10 CFR 50 4(b)(2).
Should you have any questions or require any ad1Ltional information, please d
contact me.
Sin erely, p~ n G.
orn
-Nuc ear Power Group Manhger CRH/MJB Attachment ec:
H.R Borchert Department of Health 3
State of Nebraska NRC Ragional Adminintrator Region IV Arlindron, TX i
NRC Resident Inspector Cooper Nuclear Station
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S. Nuclear Regulatory Commission u.
Page 3 of 3 May 4, 1992 STATE OF NEBPASKA)
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PIATTE COUNTY
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is an authorized deposes and says that he C.R Ih a, being first duly sworn, a public corporation and representative of the Nebraska Public Power District, that he is duly authorized to politisal subdivision of the State of Nebraska,this request on behalf of Nebra and that the submit d
d belief.
statemer s contained herein are true to the best of his knowle ge an
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1 h k day of Subscribed in my presence and sworn to before me this 1992.
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l REVISED TECilNICAL SPECIFICATIONS ELIMINATION OF MAIN STEAM LINE RADIATION MONITOR REACTO2 SCRA!i AND MSIV CLOSURE FUNCTIONS Revi sed f.c.gr.s.
29 50 30 52 33 63a 34 68 35 78 36 81 39 C '.
I.
INTROAVCTION The hebraska Public Fower District (District) requests that the NRC approve the proposed changes to the Cooper Nuc loar Station (CNS) Technical
'3pecifications described below.
The proposed changes remove the requirements associated with the Main Steam Line Radiation Monitor (MSLPJi) ceactc.r acron and Group 1 Centainment Isolation functions.
The Group 1 isolation consists of the Main Steam Isolation Valves (MSIVs) and the Main Steam Line Drain Valves.
These Technical Specification changea, reflect the removal of ' hose functions as discussed in licensing topical repott NEDO-314001 which was accepted by the NRC staff in its safety evaluation addressing the proposed modifications.2 The plant modifications associated with this proposed change will provide a number of operational benefits, while improving radiological release management associated with the Cortrol Rod Drop Accident (CRDA). Removal of the Group 1 Contai.tment Isolati: n and reactor acram froin the MSLRH will eliminate inadvertent MS1V closures and reactor scrams associated with spurious MSLBM actuations. Eliminating the MSIV closure will also retain the availability of the condenser for decay heat removal following a Finally, following the unlikely occurrence of a CRDA, maintaining scram.
steam flow to the condenser would enable some of the activity to be processed through the Augmented Off Gas (A0G) System, thereby reducing the offsite dose consequences with respect to the design basis CRDA analysis.
2 NEDO-31400, 'Saf ety Evaluation for Eliminating the Boiling Vster Reactor Main Steam Line Isolation Valve Closure Function and Scram Fuc.ction of th Main Steam Line Radiation Monitor," General Electric Company, May 1987.
2 Letter from A. C. Thadani (NRC) to G J. Beck (BWROG) dated May 15, 1991, " Acceptance for Referencing of Licensing Topical Report NEDO-31400, ' Safety Evaluation for Eliminating the Boiling Water Reactor Main Steam Line Isolation Valve Closure Function and Scram Function of Main Steam Line Padiation Monitor.'"
i Attachmert to NSD920302 Page 2 of 7 III.
DISCUSSION l
As a result of the Boiling Water Reactor Owners' Group (BWROG) Main Steam lins Radiation Monitor Committee efferts, the BVROG transmitted NEDO 31400 to the NRC. This topical repart provided the results of an evaluation of
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l the consequences of a CRDA assuming 1) the MSIVs close on high steam line radiation following a CRDA as presently assumed in the CNS CRDA analysis, and 2) the MSIVs do not close on high steam line radiation following a CRDA.
Following further information exchange betw en the BWROG and NRC i
Staif, the Staff issued its Safety Evaluation ac.:cpting reference to l
NEDC 31400 in license amendment applications seeking to eliminate the ceaetor scram and Group 1 Containment Isolation closure functions from the MS LRM.
The -NRC Safety Evaluation concluded that removal of the MSLRM Rev.ctor Scram and Group 1 Containment Isolation closure innetions is acceptable.
The NRC Safety Evaluation further concluded that patticipating BWR utilities listed in '"able 1 therein may reference NEDO 31400 !.n support of their license amendment applications provided:
1.
The applicant demonstratas that the assumptions with regard to l
input values (including power per assembly, Chi /Q, and decay l
times) that are madn in the generic analysis bound those for the plant.
l 2.
The applicant includes sufficient evidence (implenien: ed or proposed operating procedures, or equivalent commitments) to prov!.de reesonable assurance that increased.aignificant levels of radioactivity in the main steam lines will be controlled expeditious 1v to limit both occupational doses and environmental releases.
3.
The applicant stardardizes the MSLRM and the Steam Jat Air Ejector of fgas radiation monitor alarm setpoint at 1.5 times the nominal full power nitrogen 16 background dose rate at the r
monitor locations, and comm!ts to promptly sampic the reactor coolant to determine possible contamination levels in the plant reactor coolant and the need for additional corrective actions, if the MSLPli or offgas radiation monitors or both exceen their alarm -otpoints.
l The District is a participating member in the SWROG MSLRM Committee, and
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is identified accordingly in Table 1 of the SER.
The-District has also evaluated the CRDA analysis for CNS and concludes that the assumptions
- used in NEDO 31400 bound those used in the CNS CRDA accident analysis. In addition, the ' District commits to revise its proudures as necessary to ensure that adequate controls exist to provide prompt control of j
significant increaser in Main Sceam Line activity and to promptly samp1.e the-reactor coolant upon a MSLRM alarm which will be retained at 1.5 times l
the nominal background.
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Attachment to NSD920302 Page 3 of 7 111. P1SCRIPTION OF CHANGES j
The changes to the CNS Technical Specifications consist of removing the operabilicy and surveillance reouirements m socia *.ed with the MSISM reactor scram and Groap 1 Containment Isolatio. functions while retaining the operability requirements associated with the MSlDi Group 7 isolation (Reccter Mater Sample Valves) and the Mechanica., Vacuum Pump Trip.
Q riently, the CNS Technical Specifications contain distinct operability requirements and associated action statements applicable to each of the MSIM functions.
However, the surveillance and calibration requirernents i
for the MSLP.M Group 7 and Meche.nical Vacuum Pump isolations reference the
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Reactor Protection System (reactor scram) surveillance and calibration requirements, which are the rnost restrictive.
Thernfore, this proposed 1
l change adds the surveill ice and calibration requirements to the containment isolation instrumentation table, and changei the references for the Mechanical Vacuum Pump Isolation sut7eillance requirements to direct operators to the cot responding MSLRM surveillance requirernents in t.he - containment isolation instrumentation table.
The specific changes proposed to the CNS Technical Specifications are detailed below, at.d the revised CNS Technical Specification pages are provided at the end of this attactu ent, Main Steam Line Radiation Monitor RMP-RM 251 A,B,C & D is Page 29 ren.oved from Table
- 3. L 1,
" Reactor Protection Sys teia
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Instrumentation Requirements.
This eflects removal of the MSLRM scram function.
Prge 30
- The corresponding Action Statement "D" is removed from the notes for Table 3.1.1 as this statement. addressed inoperabi#ity of the MSLRM scram function, Page 33
- Main Stearn Line Radiation. Monitor RMP-RM-251 A,B,C & D is removed f rom Table 4,1.1,. " Reactor Protection System (Scram Instrumentation) Functional Tests, Minircum Functional Test Frequencies For Safety Instrumentation and Control Circuits."
This deletes the surveillance requirements associated with the MSLRM scram function.
l Page 34 Note "4"
is deleted, as this n.-
applied only to. the surveillance associated with RMP-RM-251 - A, B, C &
D.
This information is relocated as a new note to Tabl e - 4. 2 A,
" Primary Containment and Reactor "essel Isolation System Test and Calibration Frequencies,"
The MSLRM is removed fron, Table 4.1. 2,
" Reactor Protection Page 35 System (Scram) Instrument Calibration hin! mum Calibration Frequencies For Reactor Protection Instrument Channels. " This deletes the calibration requirements associated with the MSLRM scram function.
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Attachment to NSD920302 Page 4 of 7 Note "3"
is deleted, as thin note applies only to the Page 36 calibration associated with RMP RM 251 A,B,C &
D.
This J
fnformation is salocated as a new note to Table 4.2.A,
" Primary Containment and Renctor Vessel Isolation System Test and Calibration Frequencies."
Page 39 - The discussion in the Bases section for Specification 3.1 that high MSLRM signal is relates to the reactor scram on a deleted.
1ew Action Statement "E"
is referenced to reflect the Page 50 inoperability of the Group 7 isolation on high Main Steam Line radiation, as discusced further in the discussion for page 52 below.
Page 52 TNew Action: Statement "C"
is provided to direct isolation of the Reactor Water Sample Valves (Group 7) if the MSLRM becomes
' inoperable,-
In addition, the MSLRM is removed from the Group l' Containment Isolation signal list.
Page 63a - An editorial change is made to Action Statement
"'t.".
The surveillance requirements for the HSLRM have been added to Page 68 Table 4.2. A, " Primary Containment and Reactor Vassel Isolation Sys te;n - Test and Calibration. Frequencies."
The MSLRM surveillance requirements were previously provided in Tables
'4;1.1 and 4.1.2 which provided the surveillance requirements for the MSLRM associated with the Reactor Protection bystem function, but are being removed from.those tables as discusced
.-above. -Additionally, the functional; tant frequency has been-changed from once/ week to once/ month which reflects removal of.
the Reactor Protection System function of the MSLRM,1 and provides a surveillance frequency consistent with the balance of the Primary Containment-Isolation. Sy:: tem instrument channels. In addition, references to new Notes (13) and (14)-
were added to address unique survcillance requirements associated with the MSLRM as discussed in more detail below.
- Page-78 Previously Table 4.2.D,
" Minimum Test and Calibration Frequencies - For Radiation Monitoring Systems," referenced Tables y 4.'1.1 and 41_.2 for the surveillance requirements.
associated with the Mechanical Vacuum Pump isolation (provided by the" MSLRM).
This is revised to reference relocation of these surveillance requiremer"s to-Table 4.2.A as di9 cussed above.
Page 61 - Note 5'is revised to delete reference to the MSLRM. New notes
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(13) and (14) have been added to address unique surveillance requirements associated with the MSUGI. This information was previously provided in notes to Tables 4.1.1 and 4.1.2.
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Attachment to NSD020302 Page 5 of 7 Page 84 The bases Section for Specification 3.2 has been revised to correspond with the rer oval of the MSIV closure function from the MSLRM.
Additional discussion was added to address the MSLRM alarm and Group 7 (Reactor Water Sample Valves) isolation functions.
IV.
SIGNIFICANT HAZARDS DETEPJ@&TJ,QH 10 CFR 50.91(a)(1) requires that licensee requests for r* rating license amendt ents be accompanied by an evaluation of significant hazards posed by the issuance of the amendment.
This evaluation is to be performed with respect to the criteria given in 10 CFR 50.92(c). The following analysis meets these requirements.
Evaluat5on gf this Amenittnent with Resnect to 10 CFR 50.92 The enclosed Technical Specifications change is judged to involve no significant hazards based on the following:
1.
-Does the proposed change involve a significant - increase in the probability or consequences of an accident-previously evaluated?
Evaluation The proposed Technical Specification changes associated with removal of the Group 1 Containment isolation and reactor scram functions from the Main Steam Line Radta ion Monitor (MSLRM) do not constitute a signsficant increase in the probability or consequences of an
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accident previously evaluated. Removal of these functions does not involve any hardware changes which could increase the frequency of occurrence of any accident previously. evaluated, as no new failure modes will be. introduced.
For all previously analyzed accidents except the Control Cod Drop Accident (CRD/-), reactor scram and Main Stram.Line---isolation. are ' expected to occur through other single failure proof means prior to actuation of the MSLRMs. Therefore, no credit = is taken in any accident ' analysis for - these functions occurring as the result of_ actuation of the ISLRMs, with the exception of the ;CRDA, which is discussed in more detail below.
Therefore, the proposed changes to the CNS Technical Specifications, and the associated plant hardware changes do not constitute a sigaificant increase in the probability or consequences of an accident previously evaluated.
t Although a Control Rod Drop Accident assumes that Main Steam Line Isolation Valvo (MS1V) isolation would occur as the result of increased coolant activity due to a failure of fuel rods, the CRDA analysis. conservatively assumeu that all activity calculated to be available for _ transport to _ the ' condenser is transported to the condenser prior to closing of the MSIVs.
Further, in accordance with the _ analysis provided in NEDO-31400 which the District has determined conservatively bounds the CRDA analysis for CNS,
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Attachment to NSD920302 Page 6 of 7 maintaining the MSIVs in the optn position following a CRDA doci not involve a cignificant increase in the consequences of the CRDA. In i
fact, it has been determined as documented in NEDO-31400 that j
processing a portion of the activity resulting from a CRDA through the CNS Augmented Offgas System (AOC) would reduce the potential offsite exposures resulting from the accident by reducing the amount of activity available for leakage from the condenser directly to the environment.
In addition, maintaining the MSIVs open would also retain availability of the condenser for decay heat removal following such an event.
Additionally, while the analysis conducted for the BWROC as described in NEDO 31400 indicates an insignificant increase in reactivity control failure (1.4 X 10 events / year) as a result of removing the MSLRM scram function, this is offset by a reduction in transient initiating events caused by spurious reactor scrams from the HSt.RMs which results in an approximate 0.3% reduction in core damage frequency.
This repreaei*s an overall net improvement in safety.
Therefore, based on this and the above discussion, the District concludes that this propoced change does not involve a significant increase in the probability or consequences of an accident previously evaluated.
2.
Does-the proposed change create - the possibility for a new or different kind of accident from any accident previously evaluated?
Evaluation This proposed change does not involve any plant hardware changes which could int oduce any new equipment fullure modes or effects, nor does it institute any new mode of operation other than that discussed above and in NEDO-31400, which has been accepted by the NRC Staff.
The new mode of operation discussed above constitutes improved processing of potential activity following the un1 6ely event of a CRDA, and does not impart the potential for any new accident modes. Therefore, this proposed change does not craate the possibility for a new or different kind of accident from any accident previously evaluated.
j 3.
Does the proposed change create a significant reduction in the margin of safety l?
Evaluation As discussed above, the reduction in reactivity control reliability gesulting from elimination of the MSLRM scram function has been own to be negligible (1.4 X 10 events / year). This is offset by 4 duction in the frequency of transient-initiat.ing events caused y spurious scrams associated with the MSLRM, with a calculated decrease la core damage frequency of 0.3%.
This represents an overall net increase in safety; therefore, this proposed change does not create a significant reduction in the margin of safety.
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Attachmer,t to NSD920302 Page 7 oi 7 V.
CONCLUSION The District has ovaluated the proposed changes described above against the criteria given in 10 CFR 50.92(c) in accordance with the requirements of 10 CFR 50.91(a)(1). This evaluation has determined that this proposed change vill act 1) involve a significant increase in the probability or consequences of an accidant previously evaluated, 2) create the possibility for a new or different kind of accident from any accident previously evaluated, or 3) create a significant reduction in the margin of safety.
Therefore, for the reasons detailed above, the District requests NRC approval of this Proposed Change No. 100.
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