ML20072F982
| ML20072F982 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 06/10/1983 |
| From: | Gallagher J PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | Allan J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| REF-SSINS-6820 IEB-83-03, IEB-83-3, NUDOCS 8306280235 | |
| Download: ML20072F982 (8) | |
Text
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9 PHILADELPHIA ELECTRIC COMPANY 2301 MARKET STREET P.O. BOX 8699 JOSEPH W. GALLAGHER auctnic encoucv on osranrusar (2151841 5003 June 10, 1983 Docket Mos. 50-277 50-278 IE Bulletin 83-03 Mr. James M. Allan, Acting Administrator Region 1 U.S. Nuclear Regulatory Commission Office of Inspection and Enforcement 631 Park Avenue King of Prussia, PA 19406
Dear Mr. Allan:
The USNRC letter of March 10, 1983, forwarded IE Bulletin 83-03 concerning " Check Valve Failures in Raw Water Cooling Systems of Diesel Generators."
The Action To Be Taken By Licensees are restated below along with the Philadelphia Electric Company response.
Recuired Actions For Holders Of Operating Licenses:
1.
Licensees are requested to review the plant Pump and Valve In-Service Test (IST) program required by Section XI of the ASME Boiler and Pressure Vessel Code and nodify it if necessary to include check valves in the flow path of cooling water for the diesel generators from the intake to the discharge.
Those portions of the cooling water system which do not directly supply the diesel may be excluded from this review.
For example, if the cooling water to the diesel is the supplied by the normally operating service water system, loop of piping to the diesel from the service water piping and back must be considered, but not the complete service water system.
For those cooling water systems which come into operation only upon demand for diesel cooling, all portions of the system which are required to change state f
must be reviewed.
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m Mr. James M. Allan Page 2
2.
For the valves described in (1) above, licensees are requested to examine the IST program and modify _it if necessary to include verification procedures that confirm the integrity of the valve internals.
This may be accomplished by using both a_ forward flow and a back flow test or by valve disassembly and inspection.
Other equally effective means of
' assuring integrity of the valves may be used.
A reasonable schedule for the test of these valves shall also be included in the IST program.
3 3.
Licensees are requested to perform initial valve integrity verification procedures for the valves identified in (1) above using the methods described in (2) above, to be completed by the end of the next refueling outage commencing after April 1,
1983.
4.
Licensees are requested to submit a report to the NRC within 90 days of the date of this bulletin, which lists the valves identified in (1) above and describes the valve integrity verification procedure methods and schedule identified in (2) above.
This report should include the history of any known previous failures of these valves at your plant.
5.
Licensees are requested to submit a report to the NRC within 90 days of completion of the results of the initial valve integrity verification procedure performed in accordance with (3) above.
For those valves which are found to have undergone either partial or complete disassembly of valve internals, a description of the failure mode should be 4
included.
6.
The written reports required shall be submitted to the appropriate Regional Administrator under oath or affirmation
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under provisions of Section 182a, Atomic Energy Act of 1954, as' amended.
The original copy of the cover letters and a copy of the reports shall be transmitted to the U.S. Nuclear Regulatory Commission, Document Control Desk, Washington, D.C.
20555 for reproduction and distribution.
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Mr. James M. Allan Page 3
f PECo Response i
The Peach Bottom diesel generators are cooled by their own closed cooling water system which ultimately rejects the heat thru an intermediate heat exchanger to the Emergency Service Water System.
The Emergency Service Water (ESW) System is backed up by the Emergency Cooling Water (ECW) System, a closed loop system cooled by the Emergency Cooling Towers.
The four diesel generators are shared by Units 2 and 3.
Figure 1 is a diagram describing the systems supplying coolant to the diesel generator systems.
The raw water coolant lines are shown darkened to identify the flow path.
Our investigation revealed two check valves which could fail and possibly prevent coolant from reaching the diesel generators as described in the bulletin.
With respect to the request to identify those check valves in the coolant path, the fellowing valves are in the direct flow path for the diesel generators:
0-515 A ESW Pump Discharge Check (Chapman 20")
0-515 B ESW Pump Discharge Check (Chapman 20")
To date, the oniv problem encountered with these valves has been an external counterweight lever arm that fell off the ESW discharge _ check (0-515) when a screw attaching the arm loosened, most likely due to vibration.
The arm was reassembled, adjusted, and the screws staked.
The listed valves are already included in the Inservice Inspection Program and Surveillance Testing Program and are tested quarterly.
valves 0-515 A/B can be visually observed to open and close by verifying movement of the counterbalance arm on the valve.
The Surveillance Test will be modified to include a system pressure check for each pump (A & B) to verify the opposite check valve is properly seated against a back flow.
The opposite pump will also be checked for backward rotation to verify proper seating of the valve.
The Emergency Cooling Water System also has three check valves in its flow path.
These are identified as:
0-506 ECW Pump Discharge Check (Chapman 18")
0-504 A ECW Booster Pump Discharge Check (Chapman 16")
0-504 B ECW Booster Pump Discharge Check (Chapman 16")
_. = _
Mr. James M. Allan Page 4
These valves are also included in the Inservice Inspection Programs and the Surveillance Testing Program on a once per operating cycle schedule.
The valves are presently tested only in the forward (open) position.
No problems to date have been identified with these valves.
The Surveillance Test covering these valves will also be modified to include a test to verify proper seating of these valves.
Any suspected leakage would initiate corrective maintenance on the valves.
In addition to the check valves described, the diesel generator closed cooling water system contains several check valves as shown in Figures 2A and 2B.
The valves are 4" and 5" check valves.
Maintenance in the past determined that the springs in these valves were sometimes weak or broken.
The Preventative Maintenance Program was revised to require that these valves be disassembled, inspected and rebuilt during the j
annual inspection and overhaul of each diesel generator.
No further problems with these valves have been identified since this activity was initiated approximately 2 years aao.
A two-day extension beyond June 8, 1983, for submittal of the 90-day response to the bulletin, was discussed with Lowell Tripp of your office by the Engineer-In-Charge of our Licensing Section, W. M. Alden, and found acceptable.
We believe that the above report meets the required I
actions requested in the bulletin.
If you have further questions, please do not hesitate to contact us.
l Very truly yours, bru ff-Attachment ccr A.
R. Blough U.S. Nuclear Regulatory Commission t -
Site Inspector Document Control Desk l
Washington, D.C.
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COMMONWEALTH OF PENNSYINANI A :
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COUNTY OF PHILADELPHIA J. W. Gallagher, being first duly sworn, deposes and says:
That he is Manager of Electric Production Department of Philadelphia Electric Company, the Applicant herein; that he has read the foregoing response to I. E.
Bulletin R3-03 and knows the contents thereof; and that the statements and matters set forth therein are true and correct to the best of his knowledge, information and belief.
O yJ_0 ty k u
o subscribed and sworn to Yi before me this/8 day l
of
/983 l
Notary Public l
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PATRICIA D. SCHOLE l
Notary Pubhc, Philadelphia. Philadelphia Co.
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