ML20248C067

Safety Evaluation Granting Licensee Request for Exemption from Technical Requirements of 10CFR50,App R, Fire Protection Program for Nuclear Power Facilities Operating Prior to 790101

ML20248C067
Person / Time
Site:	Fort Calhoun
Issue date:	05/21/1998
From:	NRC (Affiliation Not Assigned)
To:
Shared Package
ML20248C032	List: ML20248C025 ML20248C049 ML20248C067
References
NUDOCS 9806020054
Download: ML20248C067 (4)

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,j UNITED STATES NUCLEAR REGULATORY OOMMISSION

't WASHINGTON, D.C. 20 % %0001 4

9 . . . . . ,o SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO EXEMPTION FROM SECTION 111.0 OF APPENDIX R TO 10 CFR PART 50 OMAHA PUBLIC POWER DISTRICT FORT CALHOUN STATION DOCKET NO. 50-285

1.0 INTRODUCTION

Appendix R, " Fire Protection Program for Nuclear Power Facilities Operating Prior to January 1,1979," to Title 10 of the Code of Federal Regulations (10 CFR) Part 50, establishes fire protection features required to satisfy General Design Criterion 3, " Fire protection," of Appendix A to 10 CFR Part 50 with respect to certain generic issues for nuclear power plants licensed to operate prior to January 1,1979. Fort Calhoun Station was licensed to operate in 1973. By letter dated September 30,1997, as supplemented by letters dated January 29,1998, and April 23,1998, Omaha Public Power District, the licensee for Fort Calhoun Station, requested an exemption from certain technical requirements of Appendix R.

2.0 EXEMPTION REQUESTED The licensee requested exemptions from certain technical requirements of Section 111.0, " Oil collection system for reactor coolant pump," of Appendix R to 10 CFR Part 50 to the extent that it requires that certain components of the reactor coolant pump (RCP) be protected by a lube oil collection system. Specifically, the licensee requested an exemption for the following components /RCP locations:

For the RCP equipped with a Asea Brown Boveri Industrial (ABB) motor (RC-38):

Unpressurized upper bearing cooling water penetrations located 3.15" above the normal oil level.

Unpressurized lower bearing component cooling water penetrations located 1" above the normal oillevel.

Unpressurized vent line on the lower bearing resistance temperature detector (RTD) located 2.4" above the normal oil level.

Unpiessurized upper bearing RTD located 10" above the normal oil level.

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ADOCK 05000285 PDR

Unpressurized lower bearing oil level transmitter line, which has a collection pan under the threaded connections at each end.

. Motor cooling air vents.

For the RCPs equipped with a General Electric motor (RC-3A, RC-3C, and RC-3D):

. Unpressurized air vents on the anti-rotation device (ARD) located 23" above the normal oil level.

. Motor cooling air vents.

The licensee also requested an exemption from the technical requirements of Section 111.0 of

- Appendix R to the extent that it requires that a flame arrestor be installed on the lube oil coliection tank.

3.0 DISCUSSION Section 50.48 of 10 CFR Part 50 specifies that Section Ill.O of Appendix R applies to nuclear power plants that were licensed to operate prior to January 1,1979. Fort Calhoun Station was licensed to operate on September 26,1973. Therefore, Section Ill.O of Appendix R applies to Fort Calhoun Station. Section Ill.O of Appendix R requ;res that the RCP be equipped with an oil collection system if the containment is not inerted during normal operation. It also requires that the oil collection system be capable of collecting lube oil from all potential pressurized and unpressurized leakage sites in the RCP lube oil systems. The leakage points to be protected include the lift pump and piping, overflow lines, lube oil cooler, oil fill and drain lines and plugs, flanged connections on oil lines, and lube oil reservoirs where such features exist on RCPs.

Section 111.0 also specifies that oil leakage shall be collected and drained to a vented closed container that can hold the en@e lube oil system inventory, in addition, Section Ill.O specifies that a flame arrestor is required in the lube oil collection system vent if the flash point 4 characteristics of the RCP lube oil present the hazard of fire flashback.

The underlying purpose of Section Ill.O of Appendix R to 10 CFR Part 50 is to provide reasonable assurance that leaking oil will not lead to a fire that could damage safety-related equipment during normal or design basis accident conditions.

4.0 EVALUATION For RCP RC-38, the licensee requested an exemption from the requirement to provide a lube

- oil collection system for the unpressurized lower bearing oil level transmitter line. This line is uniform tubing with oil collection pans installed under all threaded connection points. The unpressurized lower oil reservoir level instrumentation on th RCP motor, including the reservoir tubing, fittings, and transmit'er, is designed to mahitain structural integrity during a design basis earthquake. In Generic Letter 86-10," Implementation of Fire Protection Requirements," April 24,1986, the staff stated that where the RCP oil collection system and associated appurtenances are seismically designed, it is only necessary to assume that random

A 3-l leaks from the joints, as opposed to the line, could occur during the lifetime of the plant. The unpressurized lower bearing oil level transmitter line is not pressurized, is uniform, has collection pans at the threaded end connections, and meets the guidance of GL 86-10.

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Therefore, there is reasonable assurance that the unprotected tubing is not a potential leakage j site and the installed configuration of the lower bearing oil level transmitter line and its oil  !

collection pans satisfy the underlying purpose of Section 111.0 of Appendix R to 10 CFR Part 50.

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With the exception of the flame arrestor and air vents, which are addressed later, the remaining exemption requests concem the lack of oil collection capability for items that penetrate tne  !

lubricating oil reservoirs above the normal oil level. The lubricating oil reservoirs are not pressurized. Therefore, during normal operation there is reasonable assurance that these l penetrations would not be a source of oil leakage. The licensee submitted information I conceming locations of the oil system penetrations for which an exemption is requested and information concerning its administrative controls to prevent overfill of the lube oil system. The  ;

penetrations are above the fill connection and administrative controls would prevent overfill of I the tube oil reservoirs. Specifically, the licensee's administrative controls include:

Oil levels in the reservoirs are tracked and trended by the system eng neer. t Specified amounts of oil are added at the direction of the system engineer. This avoids overfill of the oil reservoirs. {

Proper oil level is verified locally at the motor oil reservoirs and by remote indication in the control room using the plant computer.

Alarms would indicate in the control room if the reservoirs were overfilled allowing the operators to stop the activity before significant lube oil spillage occurred.

On the three General Electric motors, significant overfilling would flow back out i the fill connection into the collection system.

The physical arrangement of items that penetrate the lubricating oil reservoirs above the normal oillevel coupled with the licensee's administrative controls provide reasonable assurance that I with respect to these penetrations, there would be no potential leaking oil that could lead to a  !

fire that could damage safety-related equipment. Therefore, the underlying purpose of Section 111.0 of Appendix R to 10 CFR Part 50 is satisifed with respect to these penetrations, notwithstanding the absence of a collection system. l The licensee also requested an exemption from the technical requirements of Section 111.0 of Appendix R to the extent that a flame arrestor is not provided for the RCP oil collection system tank vent. In its submittal, the licensee stated that its analysis concluded that a flashback I hazard is not present. Section Ill.O of Appendix P, specifies that a flame arrestor is required "if the flash point characteristics of the oil present the hazard of fire flashback." Since this is not i

the case for the oil used at Fort Calhoun Station, an exemption is not required. The staff did

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d not review the licensee's analysis ar. part of this safety evaluation. The licensee should maintain its analysis onsite for future NRC audit or inspection.

The licensee requested an exemption from the technical requirements of Section Ill.O of Appendix R to the extent that it has not provided lube oil collection capability for the air vents on the ARD housing and the motor cooling air vents for RC-3A, RC-3C, and RC-3D, and the motor cooling vents of RC-38. Operating experience shows that minor amounts of air-entrained lube oil may be deposited in the vicinity of the reactor coolant pump through such vents during normal plant operation. However, tne vents are not a part of the RCP motor lube oil system.

Therefore, Section 111.0 of Appendix R does not require that they be protected by a lube oil collection system and an exemption is not needed for the motor vents.

5.0 CONCLUSION

S On the basis of its review and evaluation of the aforementioned licensee submittals, at documented above, the staff concludes that for RCP RC-3B an oil collection system is r,ot needed to satisfy the underlying purpose of Section 111.0 of Appendix R for (1) the unpressurized upper bearing cooling water penetrations located 3.15" above the normal oil level, (2) the unpressurized lower bearing component cooling water penetrations located 1" above the normal oil level, (3) the unpressurized vent line on the lower bearing RTD located 2.4" above the normal oil level, (4) the unpressurized upper bearing RTD located 10" above the normal oil level, and (5) the unpressurized lower bearing oil level transmitter line. In addition, the staff concludes that an exemption with respect to these unpressurized sites is authorized by .

law, will not present an undue risk to public health and safety, and is consistent with the common defense and security. The licensee's request for exemption from the technical requirements of Section 111.0 of Appendix R to 10 CFR Part 50 for these locations should, therefore, be granted.

On the basis of its review and evaluation of the aforementioned licensee submittals, as documented above, the staff concludes that an exemption is not needed for (1) the motor cooling air vents of RCP RC-3B, (2) the anti-rotation device air vents and the motor cooling air vents of the remaining RCPs, or (3) the lack of a flame arrester for the RCP oil collection system vent.

Principal Contributor: P. Qualls Date: May 21, 1998 L

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