ML20028C443

Responds to IE Bulletin 78-03, Potential Explosive Gas Mixture Accumulations Associated W/Bwr Offgas Sys Operations. Mods Converting Present Loop Seals to Common Large Diameter Reservoir in Progress

ML20028C443
Person / Time
Site:	Brunswick, 05000000
Issue date:	03/29/1978
From:	Utley E CAROLINA POWER & LIGHT CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20027A594	List: ML20028C411 ML20028C420 ML20028C424 ML20028C428 ML20028C431 ML20028C433 ML20028C435 ML20028C437 ML20028C443 ML20028C446 ML20028C449 ML20028C451
References
FOIA-82-545, REF-SSINS-6820 GD-78-868, IEB-78-03, IEB-78-3, NUDOCS 8301100167
Download: ML20028C443 (3)

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Carolina Power & Light Company March 29,-1978 FILE: NG-3516 (3) . SERIAL: GD-78-868 Mr. James P. O'Reilly, Director U. S. Nuclear Rep J.atory Commission Region II, Suite 1217 230 Pear.htree Street

- Atlanta, Georgia 30303 BRUNSWICK STEAM ELECTRIC PLANT, UNIT NOS. 1 & 2 LICENSE NO. DFR-62 AND DPR-71 DOCKET NO. 50-324 AND 50-325 -

RESPONSE TO IE BULLETIN 78-03

Dear Mr. O'Reilly:

In response to IE Bullecin 78-03 concerning Off-Gas System explosive gas mixtures, Carolina Power & Light Company submits the following information.

A review of operations and. maintenance. procedures related to the Off-Gas System has determined that i;he system is being operated in accordance with all design parameters.

In order to prevent inadvertent actions which =ight cause ignition of the gases in the off-gas piping, the following actions have been taken:

1. Gas mixture samples are taken on initial entry and during work in areas where the potential exists for explosive gas mixtures.

2. Spark-proof tools are used in areas where explosive gases nay exist.

3. A recent evaluation of the Off-Gas Piping Grounding System was made to ensure all sections of the piping are properly grounded. Additional grounding was added in several areas to improve the existing installation.

4. Personnel have been instructed in the dangers which may exist in the areas of the off-gas piping due to f explosive gas mixtures.

l 5. Nonsparking valve trim as installed on four of the Off-Gas System valves (2-0G-ECV-103 & 104 and 1-0G-HCV-103 & 104) to reduce the possibility of off-gas ignition due to valve seat sparking.

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4 Mr. James P.-O'Reilly March 29,.1978 The ventilation in ventilated areas through which the Off-Gas-System passes has been determined adequate to dilute the explosive gas mixtures, resulting from pipe-breakage, to values less than the icwer explosive gas limit. There are five areas through which _the off gas piping passes that are not ventilated.

These areas 'are the Uni; No.1 and 2 valve pits, and the Unit No.1 Unit No. 2, and standby stack filter pits. Access to these areas is provided by removing the heavy concrete shield

' plugs which constitute the pit covers. Portable ventilation-can be used to ventilate the stack filter pits if necessary.

The present method used to detect explosive gas mixtures is a portable, hand-operated explosive meter._ Another indication that an explosive gas mixture may exist in the stack filter pit is the area radiation monitor located L2 the stack filter area.

The area radiation monitor alarms on high radiation levels that

' exist when an off-gas leak develops and keys the control room operator loop seals.to remotely isolate the filter house off-gas piping I

Also, an Off-Gas Filter House' Combustible Gas Detection System has been budgeted for 1978. This proposed detection system will have one detector in each of the three pits in the stack filter house and will be connected electrically to a monitor located outside the filter house.

' There are presently 13 Off-Gas System loop seals in the stack filter house.and two off-gas loop seals in each reactor building.

The stack filter house loop seals automatically isolate at 16 inches of water differential pressure. The reactor building off-gas loop seals are 50-inch seals and do not have an automatic isolation signal.

Modifications are in progress that would convert the present loop seals to a common, large diameter reservoir. The reservoir would provide a self-healing loop seal and will have a level switch controlled make-up water valve in case make-up water.fs needed. The individual loop seal drains will be connected in such a manner to prevent communication of the gas between drain lines. The top of the reservoir will be sealed and vented to the off-gas stack.

This would prevent off-gas from escaping from a blown loop seal to the building atmospheres.

At present, no emergency instructions exist for off-gas explosions, but one is planned and will be i=plemented by July 1, 1978. A special instruction is used to extinguish any off-gas piping fire that may occur.

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Mr. James P. O'Reilly March 29,1978 We trust.this information is suitable for your use.

Very truly.yours,

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Senior Vice President Power Supply WEA:DCS:dej e

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Report Nos.: 50-324/78-18 and 50-325/78-18 Docket Nos.: 50-324 and 50-325 License Nos.: DPR-62 and DPR-71 Licensee: Carolina Power and Light Company 336 Fayetteville Street Raleigh, North Carolina 27602 Facility Name: Brunswick Steam Electric Plant, Units 1 and 2' Inspection at: Brunswick site, Southport, North Carolina Inspection conducted: August 8-11, 1978 g inspectors: G. L. Troup J. H. Davis i

Reviewed by:

A. F. Gibson, Chief 1v/ f 9luh{

Date Radiation Support Section Fuel Facility and Materials Safety Branch Insnection Summarv Inspectico on August 8-11, 1978 (Report No. 50-324/78-18 and 50-325/78-18)

Areas Insnected: Routine, unannrunced inspection of radiation protection program including qualifications of new radiation control personnel; radiation protection training; changes to radiation protection procedures; external exposure control; internal exposure control; posting, labeling and control of radiation and contamination areas; neutron monitoring pract. ices; airborne effluent :conitoring, and review of IE circulars and bulletins.

The inspection involved 53 inspector-hours on-site by two hTC inspectors.

Results: Within the ten areas inspected, no itecs of noncocpliance or deviations were found in nine areas; ode apparent iten of noncompliance was found in one area [ infraction: control of high radiation areas (324/335/78-18-01)].

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and 50-325/78-18 I-5 protection to the exposure file. Licensee representat es stated that closer attention would be given to foll'oving the ; ocedure and that the training records would be in-corporated into the individual's exposure file in the RCET office. The inspector pointed out that this was especially i=portant since the RC&T cffice is the point frcm which respirators are assigned and issued to individual users (324/325/78-18-03).

c. Respiratory Protection Practices Examination by an inspector of the respirator users log for 1978 revealed that respirator assignments were cade by RC&T personnel as required by procedures. By cross-reference, the inspector verified individual respirator usage with appropriate air sa=ple records and confirmed that no exposures in excess of 40 MPC-E3 had occurred; therefore no investigations were necessary under 10 CTR 20.103. These records further indicated that no exposures had occured in excess of 2 MFC-br/ day or 10 MPC-br/ Week.

Examination of respirator inspection, decontamination, and survey record.s for 1978 revealed that respirators were inspected and

()) decontaminated following use as required by licensee procedures.

Discussion with licensee representatives revealed used respirator filters were discarded after being used once. The inspector discussed with licensee representatives the merits of more careful documentation of surveys performed on respirators, to include direct radiation survey results ,and resurvey result when radiation /

radioactivity levels exceeded action levels presented in licensee procedures. Licensee ' representatives stated that survey results vould be fully documented (324/325/78-18-04).

8. IE Circulars and Bulletins

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l a. Balletin 78-03, " Potential Explosive Gas Mixture Accumulations

! Associated with BWR offgas systec Operations." The licensee's review and evaluation of the bulletin are contained in CP&L. letter serial GD-78-868 of March 29, 1978. An inspector review the licensee's evaluation and associated plant procedures, and discussed the bulletin with licensee representatives. The inspector provided several editorial comments to licensee representatives regarding the e=ergency instruction procedure; these co= cents we're acknowledged by a licensee canage=ent representative. The inspector determined that two actions in the CP&L letter vere incomplete concering installation of a combustible gas detection syste= in the offgas filter house and modifications for the loop seals. The inspector reviewed the progress of these itecs with licensee representatives

(}) 'and was inforced that installation of the gas detection syste: vas l

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RII Report Nos. 50-324/78-18 and 50-325/78-18 I-6 awaiting receipt of parts and the loop seal modification was proceeding with prefabrication and would ,be ins alled when plant

. conditions per=itted. The inspector informed licensee canagement that the installation of the modifications would be reviewed at a later tioe (32t/325/78-18-05).

b.Bulletin 78-07," Protection Afford by Air-Line Respirators and Supplied-Air Hoods." This bulletin describes conditions under which the protection factors for air-line respiratory protection devices must be reduced from previously assigned values. An inspector discussed the licensee's review and actions on the bulletin with licensee representatives. A licensee representative informed the inspector that the plant only uses air-supplied masks in the continous flow mode and that air-supplied hoods are not used. After discussing the use of air-line respirators, the inspector informed licensee management that he had no further questions on this bulletin.

c. Circular 78-03, " Packaging Greater Than Type A Quantities of lov Specific Activity Radioactive Material for Transport." An inspector discussed the methods for assuring that shipments of radioactive

@ materials comply with 10 CFR 71.12 with licensee representatives. .

The representatives informed the inspector that the evaluation was still in progess. The inspector stated that the action on this circular was considered to be open (324/325/78-CI-03).

9. Monitoring of Gaseous Effluent Streams

a. An incident occured at a nuclear facility when an iodine monitor in a gaseous effluent stream indicated high release rates of iodines, resulting in evacuation of the facility. Subsequent analysis determined that the indicated high release was due to adsorption of radicactive noble gases on the charocoal filter in the monitor and the resulting anomalous readings were due to the operating characteristics of the =onitor system. An inspector di'scussed this situation with a licensee representative and reviewed the monitoring systems for gaseous effluent streams. The inspector determined that the licensee does not use an iodine monitor as the sole monitoring method on any of the effluent paths but rather

. uses a separate gas monitor in conjunction with an iodine monitor '

or uses a gas monitor by itself. Tbis would preclude a similar occurrence.

b. At another facility, an incident occured when gaseous effluent monitor gave a spurious reading due to the saturation of the Geiger - Muller detector. The inspector discussed this occurrence g

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