ML20058B813
| ML20058B813 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 10/24/1990 |
| From: | Wallace E TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| GL-89-13, NUDOCS 9010310007 | |
| Download: ML20058B813 (4) | |
Text
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TENNESSEE VALLEY AUTHORITY CH ATTANOOGA. TENNESSEE 374ol SN 157B Lookout Place 00T 241990 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C.
20555 Gentlemen:
In the Matter of
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Docket Nos. 50-327 Tennessee Valley Autbority'
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50-328 SEQUOYAH NUCLEAR P1 ANT (SQN) - REVISED PROGRAM REGARDING NRC GENERIC LETTER.(GL) 89-13. " SERVICE WATER SYSTEM PROBLEMS AFFECTING SAFETY-RELATED EQUIPMENT"
References:
1.
NRC letter to TVA dated July 16, 1990, " Generic Letter 89-13 on Service Water System Problems Affecting Safety-Related Equipment (MPA L9-13) (TAC Nos. 74061/74062) - Sequoyah Nuclear Plant, Units 1 and 2" 2.
NRC Generic Letter 89-13 Supplement 1. dated April 4, 1990
" Service Water System Problems Affecting Safety-Related Equipment (Generic Letter 89-13 Supplement 1)"
3.
TVA 1ctter to NRC dated January 26, 1990, "Sequoyah (SQN),
Browns Ferry (BFN), and Watts Dar (WBN) Nuclear Plants -
Response-To Generic Letter (GL) 89-13 Service Water System Problems Affecting Safety-Related Equipment" This 1etter revises SQN's program presented in TVA's response to GL 89-13 (Reference 3) to reflect more appropriate and equally effective test / inspection methods for the Engineered Safety Features (ESP) room coolers and essential raw cooling water (ERCW) pump motor lube oil coolers.
Reference-1 provided NRC's ovaluation of TVA's response to GL 89-13 and concluded that SQN's then proposed actions were acceptable. of Reference 3 contained a commitment (Item 2) that described SQN's tert / inspection program for implementing the recommendations of GL 89-13. -
TVA has determined that test methods originally proposed for SQN's ESF room coolers would not provide meaningful test results.
In addition, TVA has-determined that a representative test could be performed on SQN's ERCW pump motor lube oil coolers as opposed to the periodic inspection and maintenance program previously proposed. Accordingly. TVA proposes to revise the initial program to include alternative test / inspection methods for SQN's ESF room coolers and ERCW pump motor lube oil coolers.
These methods remain consistent with the requirements of GL 89-13 and the guidance provided in Supplement 1 to GL 89-13.
TVA's original schedule for implementing SQN's test / inspection program remains unchanged.
1 9010310007 901024 ADOCK 0500 7
{DR An Equal Opportunity Employer
v U.S. Nuclear Regulatory Comission 00T 241980 The enclosure provides a discussion of the changes to TVA's program for fulfilling the requirements of GL 89-13. No new comitments are contained in this submittal.
Please direct questions concerning this issue to Don V. Goodin at (615) 843-7734.
Very truly yours, i
TENNESSEE VALLEY AUT110RITY
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kE.G.Wallace, Manager Nuclear Licensing and Regulatory Affairs Enclosure cc (Enclosure):
Ms. S. C. Black, Deputy Director Project Directorate II-4 U.S. Nuclear Regulatory Comission One White Flint, North 11555 Rockville Piko Rockville, Maryland 20852 Mr. J. N. Donohew Project Manager U.S. Nuclear Regulatory Comission One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852 NRC Resident Inspector Sequoyah Nuclear Plant 2600 Igou Ferry Road Soddy Daisy Tennessee 37379 Mr.'B. A. Wilson, Project Chief U.S. Nuclear Regulatory Comission Region II 101 Marietta Street, NW, Suite 2900
' Atlanta, Georgia 30323 4
ENCLOSURE 1
By letter dated January 26, 1990 TVA submitted its response to GL 89-13 for Sequoyah and Watts Bar. of the January 1990 letter contained SQN's response to Actions I through V of the CL. contained a summary list of commitments for both plants.
Item 2 of Enclosure 3 contained a SQN commitment for implementing a program to verify the heat transfer sepability of SQNs safety-related heat exchangers. This commitment, as stated, is provided below:
"SQN will implement a continuing test / inspection program (18-month frequency) to verify the heat transfer capability of the safety-related heat exchangers listed in Enclosure 1.
Initial testing / inspection for Unit 2 will be completed prior to start-up from the Unit 2 Cycle 4 refueling outage. The initial testing / inspection for Unit I will be completed prior to start-up from the Unit 1 Cycle 5 refueling outage."
The list of safety-related heat exchangers provided in Enclosure 1 contained a description of the test / inspection methods that would be implemented at SQN.
TVA has further evaluated the test / inspection methods that were proposed for SQN's Engineered Safety Features-(ESF) room coolers (Item B of Enclosure 1) and for SQN's essential raw cooling water (ERCW) pump motor lube oil coolers (Item H.3 of Enclosure 1) end has determined that an equally effective alternative technique could be better utilized to satisfy GL 89-13 as provided by Supplement 1 to the GL.
The following provides the alternative methNs that will be implemented at SQN for these two sets of heat exchangers.
1.
ESF Room Coolers i
TVA's initial program for SQN's ESF room coolers required temperature measurements of air and water to verify heat transfer capability.
TVA has taken water temperature measurements on the inlet and outlet piping of the ESF room coolers (the cooling medium for SQN's ESF heat exchangers is the Tennessee River) and has determined that the differential tempratures across the ESF room coolers coupled with the currently available instrumentation for measuring bulk average air temperature are. insufficient to provide meaningful test data in all cases. Consequently. TVA considers testing to be impractical for each of I
the ESF room coolers.
TVA is'thereby revising the initial program for SQN's ESF room coolers (Item B to Enclosure 1 of TVA's January 1990 letter) to add the following alternative:
"For instances in which meaningful results would not be obtained by testing, periodic inspection and maintenance will be performed for biofouling, silt, and corrosion products." The intent of the above alternative action is-to test those coolers for which meaningful data can be obtained and to periodically inspect the remaining coolers. TVA considers these alternatives to be consistent with the requirements of GL 89-13 and LLe additional guidance provided in Supplement 1 to GL 89-13 (reference page 22).
c.
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TVA's initial program for SQN's ERCW pump notor lube oil coolers required
" periodic inspection and maintenance to be performed for biofouling, silt, and corrosion products."
SQN's oil coolers are located internal to the ERCW pump motor.
Consequently, disassembly is required to perform inspections of the i
coolerW. Subsequent review indicated that a representative test could be conducted for SQN's ERCW pump motor lube oil coolers. A direct J
measurement of the oil bath temperature can be obtained through the filler cap to monitor temperature and ensure oil temperatures remain below the motor manufacturer's recommended maximum. Additionally, the pump motor bearing temperature can be measured using existing plant instrumentation.
Thus. TVA is revising the initial program for SQN's ERCW pwnp motor lube oil coolers (Item H.3 to Enclosure 1 of TVA's January 1990 letter) to read as follows:
" Direct temperature measurements of the oil bath or pump i
motor bearing for each ERCW pump motor will be recorded on a minimum f requency of every refueling outage for evaluation and to ensure that oil temperature or bearing temperature remains below the manufacturers recommended maximum."
TVA considers.this test technique to be a preferred method over the periodic inspection program contained in TVA's initial program. This test technique continues to fulfill the requirements and schedule contained in GL 89-13 and Supplement I to GL 89-13.
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