ML20137H537
| ML20137H537 | |
| Person / Time | |
|---|---|
| Site: | Trojan File:Portland General Electric icon.png |
| Issue date: | 11/25/1985 |
| From: | Withers B PORTLAND GENERAL ELECTRIC CO. |
| To: | Butcher E Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20137H542 | List: |
| References | |
| TAC-60783, NUDOCS 8512020418 | |
| Download: ML20137H537 (4) | |
Text
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EM D WW5s Vce Presdyt November 25, 1985 Trojan Nuclear Plant Docket 50-344 License NPF-1 Director of Nuclear Reactor Regulation ATTN:
Mr. E. J. Butcher, Jr., Acting Chief Operating Reactors Branch No. 3 Division of Licensing U.S. Nuclear Regulatory Commission Washington DC 20555
Dear Sir:
Auxiliary Feedwater System Our letter of August 12, 1985 informed you of our intention to perform a detailed review of the Trojan Auxiliary Feedwater (AEM) System design. That review has been completed and a copy of the final report is enclosed. As sumaarized in Section 3.7 of the report, a number of recommended changes have been identified to improve system reliability. A list of the system modifica-tions to be made, and our schedule for completing them, is provided as the attachment to this letter.
In addition to the modifications identified in the attachment, we anticipate submitting a License Change Application to add safety-related surveillance requirements for the electric AFW pump to Technical Specification 4.7.1.2.
These requirements will provide routine verification of the system reliability contribution by the electric pump, and provide for increased operating flexi-bility by adding the electric pump to the limiting conditions for operation in Technical Specification 3.7.1.2.
Throughout this program, emphasis is being placed on optimizing performance and reliability, while continuing to meet system design requirements such as the long-term reliability improvement recommendations CL-2 and CL-4 provided to us in an NRC letter (Eisenhut to Goodwin) of October 3, 1979.
If you should have any questions, please do not hesitate to contact us.
M P
Bart D. Withers Vice President Nuclear Attachment c:
Mr. John B. Martin (2 copies)
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0\\ h Regional Administrator, Region V
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U.S. Nuclear Regulatory Commission i
tI Mr. Lynn Frank, Director State of Oregon Department of Energy 121 SW SJmon Drmt Po:tyd Cnayon 97204
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Trojan Nuclear Plant Mr. E. J. Butcher, Jr.
j Docket 50-344 November 25, 1985 License NPF-1 Attachment Page 1 of 3 1
j TROJAN NUCLEAR PLANT AUXILIARY FEEDWATER (AFW) SYSTEM MODIFICATIONS FOR INCREASED RELIABILITY A.
Suction / Discharge Piping and Condensate Storage Tank (CST) Modifications 1.
Upgrade the AFW pump suction piping as necessary to meet Seismic 1,
Category I and tornado protection requirements.
2.
Remove or permanently disable the conunon suction line isolation valve from the CST (MD-050).
3.
Provide two channels of safety-grade (Seismic Category I, j
tornado-protected, and Class 1E power supply) CST level i
indication.
4.
Modify the AFW pump trip circuit to optimize system reliability and maintain pump protection.
1 (NOTE: This modification will delete the AFW pump low suction pressure trips and add trip signals from low CST level to pro-j tect against CST failure.
Existing control room indication and annunciation of AFW pump low suction pressure and low CST level will be optimized and integrated with this modification.)
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5.
Replace the AFW pump suction pressure transmitters with more l
durable and reliable equipment, i
6.
Evaluate the suitability of the AFW pump suction and discharge pressure gauges and their periodic preventive maintenance requirements.
7.
Replace the AFW pump discharge pressure transmitters with more durable and reliable equipment.
B.
Turbine-Driven AFW Pump Modifications 1.
Bypass the thermal overload relays in the motor control circuit for the turbine trip and throttle valve (MO-3071).
2.
Remove the electrical overspeed trip for the turbine driver.
- 3.. Seal selected electrical components in the turbine AFW pump room against moisture.
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r Trojan Nuclear Plant Mr. E. J. Butcher, Jr.
Docket 50-344 November 25, 1985
^
License NPF-1 Attachment Page 2 of 3 I
4 4.
Correct and revise the Operating Instructions as necessary to provide instructions for setting the AFW flow control valves (CV-3004) and for realigning the pump switch positions for standby-to-autostart.
5.
Develop a detailed calibration procedure for the turbine Woodward Governor Control System.
C.
Diesel-Driven AFW Pump Improvements i
1.
Bypass the diesel engine jacket water high temperature trip on autostart.
2.
Evaluate the feasibility of bypassing the thermal overload relays on the service water cooling supply line isolation valve (MO-3060B).
3.
Develop a more detailed calibration procedure for the diesel engine Woodward Governor Control System.
4.
Submit a Technical Specification change to add surveillance requirements for the 24-volt starting battery bank and charger.
5.
Replace two timers in the diesel-pump trip circuit, and one timer in the diesel-pump start circuit with models designed for higher voltage ratings.
D.
Electric-Driven AFW Pump Modifications 1.
Connect the auxiliary lube oil pump to the same power supply as the AFW pump.
2.
Add the manual valves in the flow path to the locked valve list.
1 3.
Reset the low lube oil alarm setpoint above the pump trip set-point to provide advance warning of a possible pump trip to the operator.
j 4.
Provide loca1' indication of suction pressure and local override of the low suction pressure trip.
E.
Miscellaneous System Modifications 1.
Provide multiple pressure inputs from the main steam lines, and suctioneering of pressures, for differential pressure control between the AFW pumps discharge and the steam generators.
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e Trojan Nuclear Plant Mr. E. J. Butcher, Jr.
Docket 50-344 November 25, 1985 License NPF-1 Attachment Page 3 of 3 4
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2.
Modify equipment drains in the turbine-driven pump room to route hot condensate directly to the drain system.
l With the exception of Item D.3, which is scheduled to be completed by the end of 1986, and Items A.7, D.1, and D.4, which are scheduled to be com-plated prior to startup from the 1987 refueling outage, all of the fore-going modifications are scheduled to be completed prior to startup from the 1986 refueling outage (currently scheduled for April 24 through June 17, 1985). Completion of Items A.3, A.4, and A.5 may be impacted by the ability to procure qualified level and pressure transmitters.
During startup from the 1986 outage, AFW System testing will be performed in an attempt to identify the cause of pump-discharge pressure oscilla-tions. Also, the next time each of the pumps is disassembled for mainte-nance, the wear rings at the impeller-casing interface will be replaced with rings with graphite inserts to reduce the likelihood of pump damage in the event the pump is run under dry conditions. The wear rings in all 3 pumps will be replaced by December 31, 1987.
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