ML20114A826

Responds to 841123 Request for Addl Info Re Emergency Response Capability Items Per Rev 2 to Reg Guide 1.97 & Suppl 1 to NUREG-0737.Present Neutron Flux Instrument Acceptable Until Category 1 Instrumentation Installed

ML20114A826
Person / Time
Site:	Brunswick
Issue date:	01/22/1985
From:	Zimmerman S CAROLINA POWER & LIGHT CO.
To:	Vassallo D Office of Nuclear Reactor Regulation
References
RTR-NUREG-0737, RTR-NUREG-737 NLS-85-009, NLS-85-9, NUDOCS 8501280476
Download: ML20114A826 (6)

Text

r Cp&L Camlina Power & Light Company SERIAL: NLS-854)09 JAN 2 21985 Director of Nuclear Reactor Regulation Attention: Mr. D. B. Vassallo, Chief Operating Reactors Branch No. 2 Division of Licensing United States Nuclear Regulatory Cot. mission Washington, DC 20555 BRUNSWICK STEAM ELECTRIC PLANT, UNIT NOS. 1 AND 2 DOCKET NOS. 50-325 & 50-324/ LICENSE NOS. DPR-71 & DPR-62 EMERGENCY RESPONSE CAPABILITY CONFORMANCE TO REGULATORY GUIDE 1.9 7, REVISION 2

Dear Mr. Vassallo:

By letter dated November 23, 1984, your staff provided Carolina Power & Light Company (CP&L) with a copy of the report prepared by EG6G Idaho, Inc.

regarding conformance to Regulatory Guide 1.9 7 at Brunswick. This report contained six Regulatory Guide 1.97 items for which additional information was required.

Enclosed please find our responses to these items. In addition, clarifications pertaining to the Brunswick Position Paper on Regulatory Guide 1.97 and the Brunswick Steam Electric Plant Unit Nos. I and 2, Response to NUREG-0737 Supplement 1 - Regulatory Guide 1.97 - Application to Emergency response facilities are included. Should you have any questions concerning this submittal, please contact Mr. John S. Dietrich at (919) 836-6154.

Yours very truly, yt:- r : -

S. .mmerman Manager Nuclear Licensing Section MAT /pgp (1033 MAT) cc: Mr. D. O. Myers (NRC-BNP)

Mr. J. P. O'Reilly (NRC-RII)

Mr. M. Grotenhuis (NRC) 8501 p foh g gj F p((

i 411 Fayetteville Street e P, O. Boa t$$1 e paleign N C. 21602

ENCLOSURE 1 TO SERIAL NLS-85-009 Open Item 1 Neutron Flux - the licensee's present instrumentation is acceptable on an interim basis until Category 1 instrumentation is developed and installed.

BSEP Response The Company will keep informed of new developments in neutron monitoring instrumentation.

Open Item 2 Drywell Sump Level - the licensee should provide information describing how the level of the drywell sump is ascertained during and following an accident.

BSEP Response Brunswick has a BWR Mark I drywell with two drain sumps. The equipment drain sump collects identified leakage and the floor drain sump collects unidentified leakage. Although the level of the drain sumps could be used as a direct indication of a breach of the reactor coolant system pressure boundary, the indication would be ambiguous because of water collection in the sumps during normal operation.

The drywell-sump level signals do not automatically initiate safety-related

- -- usystems or alert the operator of the need to take safety-related actions.

Both sumps have level detectors that provide only the following non-safety indications:

1. Rate of rise of indication

2. High-level alarm (starts first sump pump)

3. High-high-level alarm (starts second sump pump)

In addition, timers are used to indicate the duration of sump pump operation and permit the amount of leakage to be estimated. Excessive leakage during normal operation requires the unit to be shut down per technical specifications.

With regard to determining the levels of the drywell sumps during and following an accident, the systems are deliberately isolated at the primary containment penetration upon receia* af an isolation signal to establish containment integrity. The drywell sumps overflow to the suppression pool.

Therefore, by design, the drywell sump-level instrumentation serves no useful accident-monitoring function. There is other instrumentation required by R.G. 1.97 which would indicate leakage into the drywell.

1. Drywell pressure - Variable B7, Category 1

2. Drywell temperature - Variable D7, Category 2

3. Primary containment area radiation - Variable CS, Category 3 (1033 MAT /pgp)

s Brunswick has identified drywell pressure and drywell temperature as Type A variables.

The Emergency Procedure Guidelines use the RPV level and the drywell pressure as entry conditions for the Level Control Guideline. A small line break will cause the drywell pressure to increase before a noticeable increase in sump level. Therefore, the drywell sumps will provide a " lagging" versus "early" indication of a leak. Based on the above discussion, additional instrumentation to monitor drywell sump level during and following an accident is not required.

Open Item 3 Drywell drain sumps level - the licensee should provide information describing how the level of the drywell drain sumps are ascertained during and following an accident.

BSEP Response Refer to BSEP Response for Open Item 2 Open Item 4 Standby liquid control system storage tank level - environmental qualification should be addressed in accordance with 10CFR50.49.

BSEP Response The Standby Liquid Control System does not require environmental qualification

.. .. _per10CFR50.p9. Refer to Carolina Power & Light Company's Environmental Qualification of Electrical Equipment Brunswick Steam Electric Plant Units 1 and 2 10CFR50.49 Day Response Submittal to Commission on May 20, 1983.

Open Item 5 Reactor building or secondary containment area radiation - the licensee should identify the range of this instrumentation, identify any deviation from the range recommended by the regulatory guide and justify any deviation.

BSEP Response In their review, EG&G Idaho, Inc. indicated that the reactor building vent closed when the radiation level reaches 5 mR/hr. Our May 8, 1984 submittal of Revision 2 of the Brunseick response to NUREG-0737 Supplement 1 - R.G. 1.97 -

Application to Emergency Response Facilities revised this to reflect reactor building vent closure at 11 mR/hr (see Variable E2, page 59 of our May 8, 1964 sub tittal).

The Company believes that Secondary Containment Area Radiation is an inappropriate parameter to use in order to detect or assess primary containment leakage. Radiation exposure rate in the secondary containment is largely a function of the radioactivity in the primary enntainment and in the fluids flowing in the ECCS piping, which cause direct radiation shine on the area monitors. The Company is concerned about local radiation exposure rate (1033 HAT /pgp)

monitors providing ambiguous indications due to the amount of piping and the number of widely scattered locations of electrical penetration and hatches.

The existing area radiation monitoring system at Brunswick can be used to monitor area radiation in various areas of the reactor building. Various ranges are provided depending on the area being monitored. The ranges vary from 0.01 - 100 mR/hr to 103 - 106 mR/hr. Also the Drywell High Range Radiation Monitors provide a range of 103 - 10lb mR/hr. The noble gas effluent monitors (Variables E4 and E5 as detailed in the BSEP Response to NUREG-0737, Supplement 1) will be used in conjunction with the existing area radiation monitors as alternate instrumentation to assess primary containment leakage.

Open Item 6 Radiation Exposure Rate - the licensee should provide instrumentation in accordance with the R.G. 1.97 recommendations.

BSEP Response ,

Radiation Exposure Rate is listed under two variable types in R.G. 1.97, Variables C14 and E3. We have found our reference to NUREG-0737, Supplemen: ;

to be inappropriate for Variable C14. The interpretation was confused with Radiation Exposure Meters. We offer the following resolution to Variable C14:

The purpose of this variable is to detect indication of a breach of primary containment. As discussed in the BSEP Response to Open Item 5, radiation exposure rate in the secondary containment is largely a function of the radioactivity in the primary containment and in the

,_ __ m . fluid.s flowing in the ECCS piping, which cause direct radiation shine on the area monitors. The noble gas effluent monitors should be used to properly detect a breach of containment. Using radiation exposure rate monitors to detect primary containment breach is neither feasible nor necessary. Noble gas effluent monitors will be used in conjunctian with existing area radiation monitors to detect a breach of containment.

We provide the following resolution to Variable E3:

Should access to the reactor building be deemed necessary, existing area radiation monitors can be used as well as portable survey instrumentation.

Additional Clarifications The following clarifications _ are to the Brunswick Position Paper on R.G. ..)~

and the Brunswick Response to NUREG-0737 Supplement 1.

1. Paragraph 1.5.g of the Brunswick Position Paper on Regulatorg Guide 1.97 The Company's position concernin*, Paragraoh 1.5.g of R.G. 1.97 was inadvertently omitted f rom Revi<, ion 1. CPOL concurs with this position.

(1033 MAT /pgp)

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2. Variable A2 (Brunswick Response to NUREG-0737 - Supplement 1) -

Reactor Water Level The Company has stated that a range of minus 180 to plus 295 inches of water is recommended for RPV water level. Our original intent was to comply with the recommended Low end range and monitor level down to the bottom of the core support plate. It was believed that a re-calibration to the existing fuel zone instrument would accomplish this so that the same instrument which is used for normal operations could also be used for post-accident. The re-calibration can be done, but will degrade the accuracy of the instrument. In light of this information, which came out of the detailed engineering of the modification, we questioned the necessity of monitoring water level to that low a level. The lowest useful level is minus 128 inches of water, as determined by calculations for formulation of the Brunswick E0P's for the steam cooling procedure. We believe a range of mir.c '0 to plus 295 inches of water meets the intent of this variable. A range of minus 150 to plus 295 inches will be provided for monitoring reactor water level. .

3. Variable A7 (Brunswick Response to NUREG-0737 - Supplement 1) -

Suppression Pool Pressure The Company has stated that a range of minus 5 to plus 245 psig is recommended for suppression pool pressure. Our original intent was to maintain consistency with the drywell pressure instrument range (minus 5 to plus 245 psig) because primary containment consists of the drywell and the suppression pool. However, ef forts to utilize existing instrumentation found re-calibration of the existing suppression pool pressure instrument (from a range of zero to plus 75 psig to the expanded range) to render the instrument useless for normal operations. Additional instrumentation to monitor this wide range was considered undesirable from a human factors standpoint.

Drywell pressure is a good approximation of suppression pool pressure; in that a one-half pound differential of drywell pressure to suppression pool pressure (drywell prensure lower) results in the opening of the vacuum breakers, and a drywell pressurc higher than suppression pool pressure is equalized through the downcomers. CP&L considers the wide range drywell pressure indication of minus 5 to plus 245 psig adequate for monitoring post-accident primary containment pressure. The present range of zero to plus 75 psig will be maintained for roanitoring suppression pool pressure.

4. Variable D25 (Brunswick Response to NUREG-0737 - Supplement 1) -

Standby instrument Air Pressure The Nitrogen Backup is a subsystem of the Instrument Air System designed to provide an independent, safety-related pneumatic source to selected safety-related loads. This system will eliminate the need to environmentally qualify the components of the non-interruptible air system as per IEB 79-01B, since it will . provide all safety grade pneumatic supply requirements. The other pneumatic loads currently (1033 MAT /pgp)

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supplied by 'the non-interruptible instrument air system have been reviewed and either f ail to the safe position following' an accident or are being modified by other plant modifications (i.e., change out to solenoid valves).

5. Note 2 on page 111 of Brunswick Response to NUREG-0737 Supplement !

. This note should read as follows:

See Brunswick position on R.G. 1.97, paragraph 1.3.le for category 1

. instruments and paragraph 1.3.2d for category 2 instruments.

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