ML20073H568
| ML20073H568 | |
| Person / Time | |
|---|---|
| Site: | Brunswick  |
| Issue date: | 04/26/1991 |
| From: | Starkey R CAROLINA POWER & LIGHT CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML19298E446 | List: |
| References | |
| NLS-91-118, NUDOCS 9105070180 | |
| Download: ML20073H568 (7) | |
Text
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CP&L Carolina Power & LhgM Company an--__,
April 26, 1991 SERIAL: NLS 91 118 10CFR50.90 United States Nuclear Regulatory Commission ATTENTION: Document Control Desk Washington, DC 20555 BRUNSWICK STEAM ELECTRIC PLANT, UNIT N0!. 1 AND 2 DOCKET NOS. 50 325 6 $0 324/ LICENSE NCS. DPR 716 DPR 62 REQUEST FOR TEMPORARY WAIVER OF COMPLIANCE REACTOR WATER CLEANUP SYSTEM DITERRENTIAL FLOW IS01ATION INSTRUMENT Centlemen:
Carolina Power & Light company herchy requests a temporary NRR Vaiver of Compliance for the Brunswick Steam Elcetric Plant (BSEP), Units 1 and 2.
This letter is a follow up to discussions with the NRR Pro' ect Manager on April 26, 1991 at the Brunswick Plant site.
Carolina Power 6 Light Company is in the process cf preparing an emergency license amendment request to revise the reactor water cleanup system dif'ferential flow isolation actuation trip setpoint and allowable setpoint values.
The proposed waiver applies to the reactor water cleanup system differential flow isolation actuation instrument trip setpoint specified in Technical Spec'ftcation 3.3.2 2, Item 2.a.
Due to the application of a revised the instrument trip and allowable setpoints instrument setpoint methodologylfications must be increased from "less than or specified in the Technical Spee equal to 53 gallons per minute" to "less than or equal to 125 gallons per minute" in order to account for instrument uncertainties; the actual, field instrument setpoint will remain the same.
The proposed waiver temporarily increases the instrument setpoint limit in order to allow sufficient time for the preparation, submittal and review of an emergency license amendment requesttopermanentlyrevIsethesetpoint.
The detailed basis for the proposed waiver is provided in Enclosure 1.
The bar.is provided in Enclosure 1 references a proprietary General Electric (CE)
Report CE NE 901 011 0391, a copy which is provided as Encionure 2.
An t.ffidavit for withholding the CE report from public disclosure is provided as.
On the basis of the.frf
'lon provided herein, Carolina Power 6 Light Company requests this
.,.iory waiver until such time as the NRC is able to revlew and approve an mergency license amendment request.
In order to avoid the delay of the start-up of Brunswick Units 1 and 2, CP6L requests that this waiver of compliance be granted prior to 1200 on April 28, 1991.
Carolina Power 6 Light Company will submit the subject license amendment request by May 3, 1991. The Plant Nuclear Safety Committee has reviewed and recommended approval of this request.
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boeument Control Desk NLS 91 118 / Page 2 Please refer any questions regarding this submittal to Mr. K. J. Ahern at (919) 457 2404.
Yours very truly, (h
Al
<f 9 R. B. Starkby Vice President Brunswick Nuclear Project RBSWRM/wrm Enclosure cc:
Mr. Dayne H. Brown Mr. S. D. Ebneter Mr. N. B. Le Mr. R. L. Prevatte
s' ENCLDSURE 1 BRUNSWICK STEAM ELECTRIC PLANT, UNITS 1 AND 2 NRC DOCKET NOS. 50 325 6 50 324 OPERATING LICENSE NOS. DPR 71 6 DPR 62 REQUEST IVR TEMPORARY WAIVER OF COMPLIANCE REACTOR WATER CLEANUP SYSTEM DIFFERENTIAL FLOW ISOLATION INSTRUMENT BASIS FOR VAIVER OF COMPLI ANCE TECHNICAL SPECIFICATION REQUIREMENTS Technical Specification 3.3.2 requires that isolation actuation instrumentation shown in Table 3.3.2 1 be operable with trip setpoints set consistent with the values specified in Table 3.3.2 2.
Technical Specification Table 3.3.2 1 requires the reactor water cleanup system isolation actuation instrument for the differential flow function be operable when the unit is in Operational Conditions 1, 2 or 3.
Technical Specification Table 3.3.2 2 requires the trip setpoint for the reactor water cleanup system isolation actuation instrument be set at less than or equal to
$3 gallons per minute.
If a setpoint cannot be established as required by Technical Specifications, the instrument must be declared inoperable.
The action required for an inoperable reactor water cleanup system differential flow instrument is to isolate the reactor water cleanup system.
Technical Specification 3.0.4 prohibits passage into higher Operational Conditions while relying on the requirements of Action Statements.
Brunswick Plant Technical Specification 3.3.2 does not include an exception to Technical Specification 3.0.4.
A Vaiver of Compliance is requested for Technical Specification Table 3.3.2 2 Item 2.a to increase the reactor water cleanup system differential flow isolation instrument trip setpoint from "less than or equal to 53 gpm" to "less than or equal to 125 gom."
Without issuance of this waiver of compliance neither Brunswick unit is permitted to start up (i.e., change OperationalConditions)sinceanexceptiontoTechnicalSpecification3.0.4is not provided in Technical Specification 3.3.2.
Start up of a Brunswick unit
~is currently scheduled to commence at approximately 1200 on April 28, 1991.
SAFETY SICNIFICANCE AND POTENTIAL CONSEQUENCES General Electric Company was requested to evaluate an increased allowable Icakage limit for the reactor water cleanup system differential flow isolation function. The General E?ectric response was provided in report CE NE 901 011 0391 (copy attached).
Ceneral Electric has indicated the sole design basis for the differential flow isolation function is to limit the release of radioactivity to maintain offsite and control room whole body and inhalation doses within the limits of 10 CFR 100 and 10 CFR 20.
The Ceneral Elcetric model is based on a 300 gpm leak un isolated for 30 days using conservative source term values.
The model demonstrates that o'ffsite and control room dose limits are not exceeded.
Therefore based on the results of theGeneralElectricmodelandanalysis,anincreaseInthereactorwater cleanup system differential flow limit above the 53 gpm limit is justifiable.
~ JUSTIFICATION FOR REQUEST The potential for the reactor water cleanup system differential flow leak detection instrument to allow system leakage ln excess of the Technical Specification limit without system isolation was identified.
As a result, an performed.g evaluation of the instrument calibration scaling factors was engineerin The recently completed calculations use a revised instrument loo accuracy /setpoint methodology based on the latest ISA recommended practices.p
Tse of this methodology results in the existing differential flow instrument loop $3 gpm limit specified by Technical Specifications. inaccuracy being too large to assure s the For Operational Condition 1 operation, leaks of up to 94 gpm could exist prior to isolation.
The leak rate prior to isolation would increase further in Operational Condittuns 2 and 3 up to a bounding leak of 112 gpm in the extreme case where reactor pressure vessel start up level control is performed by dumping through the reactor water cleanup system without reactor water cleanup system pump operation.
The instrument trip setpoint specified in the Technical Specifications must be increased from "less than or equal to $3 gallons per minute" to account for these instrument uncertainties.
In order to bound the limiting anal discussed above, a setpoint limit of *1ess than or equal to 125 gpm"ysis caso is proposed. Adoption of this increased Technical Specification limit results in no physical setpoint change in the plant.
Based on this, Cp6L believes that the reactor water cleanup system is operable and fully capable of performing its intended safety function.
Based on this sequence of events described above, Cp6L could not have reasonably foreseen or avoided the need for this temporary waiver of compliance.
EXISTING ALTERNATIVE ACTIONS The following existing alternative methods of monitoring for reactor water cleanup system leakage will enhance the probability that small leaks will be identified early enough to prevent significant propagation 1.
Operating Instruction 013.4, Attachment 3, the Auxiliary Operator Daily Chech Sheet requires that the 20' and 50' elevations of the reactor building be checked for any type of Icakage and that leaks be reported to the control room and radwaste operations once per shift (a shift is 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />, 2 shifts per day).
2.
Operating Instruction 01 3.1, Attachment 1, the Control Operator's Daily Surveillance Report requires that the reactor water cleanup system differential flow instrumentation be channel checked once every 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
Indications deviating from the expected range result in investigation for actual leaks or instrument problems.
3.
Radwaste operations performs a daily (once per 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />) check of the floor and equipment drain sump pump cumulative timers.
4 The reactor building floor drain and equipment drain sump nump out and fill rate timers initiate control room annunciators.
The individual annunciator procedures require that an investigation of the leak source be performed in accordance with plant procedure 01 04, Radwante Water Leakage Control. The procedure provides guidance for location of the leaks and requires that either reduction or satisfactory evaluation of those leaks be accomplished within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> for all leaks in excess of 40 gpm for floor sumps or 20 gpm for equipment sumps.
SIGNIFICANT HA2.ARDS ANALYSIS The Commission has provided standards in 10 CPR 50.92(c) for determining whether a significant hazards consideration exists.
Carolina power 6 Light Company has reviewed this proposed temporary waiver of compliance and determined that its adoprion would not involve a significant hazards consideration.
The basis for this determination follows:
i 1
1.
The proposed waiver does not involve a significant increase in the i
probability or consequences of an accident previously evaluated.
The i
sole design basis function for the reactor water cleanup system differentlal flow isolation fut'etion is to assure comp 11ance with the offsite and control rooin dose limitations imposed by 10 CFR 100 and 10 CFR 20.
The differential flow isolation function is not intended for protectinn of reactor pressure vessel water levels or for limiting the j
reactor building environment for environmental qualification purposes.
The proposed change to the reactor water cicanup system differential flow isolation function will not affect any initiating mechanism for a previously evaluated accident; therefore the proposed change will not significantlyincreasetheprobabilityofadesignbasisaccidentnor will the proposed change significantly increase the probability of malfunction of any safety related equipment during the requested extension.
The proposed waiver will not significantly increase the consequences of the previously analyzed reactor water cleanup system accident.
The proposed change to increase the differential flow isolation setpoint
~
from "less than or equal to 53 gpm" to "less than or equal to 125 may result in a slight increase in offsite and control room doses.gpm" However, the consequences of a reactor water cleanup system leak isolation based on the existin6 53 gpm setpoint versus the consequences of a reactor water cleanup system leak isolation based on the proposed 125 gpm setpoint in comparison to the design basis consequences of a 300 gpm un. isolated leak for 30 days is not significant.
Therefore, the company has determined that the proposed setpoint revision will have an acceptable effect on the overall safety of the plant.
2.
The proposed waiver does not create the possibility of a new or different kind of accident from any accident previously evaluated.
Only the primary containment isolation system components of the reactor water cleanup system perform a safety function.
The isolation function will continue to exist and perform its intended safety function of limiting offsite and control room doses w Thin the limits of 10 CFR 100 and 10 CFR 20.
Therefore, the proposed waiver will not create the possibility of a new or different kind of accident from any accident previously evaluated.
3.
The proposed waiver does not involve a significant reduction in the margin of safety.
The proposed change to increase the differential flow isolation setpoint from "less than or equal to 53 gpm" to "less than or equal to 125 gpm" will result in a slight increase in offaite and control room doses. Ilowever, the consequences of a reactor water cleanup system leak isolation based on the existing 53 gpm setpoint versus the consequences of a reactor water cleanup system leak isolation based on the proposed 125 gpm setpoint in comparison to the design basis consequences of e 300 gpm un. isolated leak for 30 days is not significant.
Therefore, tre Company has determined that the proposed setpoint revision will have an acceptable effect on the overall safety of the plant.
Based on this reasoning, Cp6L believes the proposed waiver does not involve a significant reduction in the mars n of safety.
i
-ENVIRONMENTAL EVALUATION 10 CPR 51,22(c)(9) provides criterion for and identification of licensing and regulatory actions eligible for categorical exclusion from performing an environmental assessment.
Carolina Power & Light Company has reviewed this exclusion set forth in 10 CFR 51.22(c)(9). request and determined that it meets the elij',ursuant to 10
' environmental impact statement or environmental assess, ment needs to be prepared in connection with granting of the tenporary waiver of compliance.
The basis for this determinat. ion followe:
1.
As demonstrated in t.he above si nificant hazards analysis, the proposed waiver does ont involve a signi icant hazards consideration The proposed waiver does not resultor significant increase in the amounts of any effluents th, in a significant chant 2.
at may be released offsite.
The proposed vaiver does not introduce any new equipment nor does it require any existing equipment or systems to perform a different type of function than they are currently designed to perform. The sole design basis function for the reactor water cleanup system differential flow isolation function is to assure compliance with the of fsite and control room dose limitations imposed by 10 CFR 100 and 10 CFR 20.
General Electric Company was requested to evaluate an in:reased allowable leakage limit for the reactor water cicanup system differential flow isolation function.
The General Electric response was provided in report GE NE 901 011 0391. The General Electric model is based on a 300 gpa leak un isolated for 30 days using conservative source term values. The analysis demonstrates that offsite and control room dose limits are not exceeded.
Other indications of a line break in the reactor water cleanup system exist, such as area temperature monitoring, which will ensure timely isolation of the reactor water cleanup system in the event of a line break.
Therefore, based on the results of the General Electric model and analysis and the alternate it is evident means of timely reactor water cleanup system isolation that an increase in the reactor water cleanup system differential flow allowable limit from $3 gpm to 125 gpm will not significantly increase the types or amounts of any effluents that may be released offsite.
3 The proposed waiver does not result in an increase in individual or cumulative eccupational radiation exposure.
No additional surveillances or testing results from the waiver.
As stated above, General Electric Report GE.NE.901 011 0391 demonstrates that control room dose limits are not exceeded even assuminy, a 300 gpm leak which is un isointed for 30 days.
In addition, other indications of a line break in the reactor water cleanup system exist, such as area temperatute monitoring, which
'ly isolation of the reactor water cicanup system in the will ensure *\\
e ovent of a line break.
No additional surveillances or testing results from the waiver. Therefore, based on the results of the General Electric model and analysis, an increase in the reactor water cleanup system differential flow allowable limit from 53 gpm to 125 gpm will not s1 nificantly increase individual or cumulative occupation radiation exposure.
/
f ENCLOSURE 2 s
liRUNSWICK STEAM ELECTRIC PLANT UNITS 1 AND 2 i
5 NRC DOCKET NOS. 50325$50324 OPERATING LICENSE NOS. DPR 716 DPR 62 REQUEt;T TOR TIMPORARY WAIVER Ol' COMPLIANGE REACTOR WATER CLEANUP SYSTEM DITFERENTIAL F1hV IS01ATION INSTRUMENT GENERAL ELECTRIC REPORT CE.NE.901 011 0391
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