ML20033F559
| ML20033F559 | |
| Person / Time | |
|---|---|
| Site: | Trojan File:Portland General Electric icon.png |
| Issue date: | 03/15/1990 |
| From: | Cockfield D PORTLAND GENERAL ELECTRIC CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| REF-GTECI-A-47, REF-GTECI-SY, TASK-A-47, TASK-OR GL-89-19, NUDOCS 9003220038 | |
| Download: ML20033F559 (4) | |
Text
i l
l.
y M
M i
e M Cortvargt David W. Cockfield Vice President, Nuclear f
. March 15, 1990 Trojan Nuclear Plant Docket 50-344 License NPF-1 If.S. Nuclear Regulatory Commission Attn: Docunant Control Desk Washington DC 20555
Dear Sirs:
Response to Generic Letter 89-19, " Safety Implication of Control Systems in LWR Nuclear Power Plants" I
Information is provided in the attachment to this letter pursuant to your request under Title 10 Code of Federal Regulations, Part.50, Section 54(f)(10 CFR 50.54(f)] describing Portland General Electric s
Company's (PGE's) response to Generic Letter 89-19, " Safety Implication of Control Systems in LWR Nuclear Power Plants".
Sincerely, Attachment et Mr. John B. Martin 3
Regional Administrator Region V U.S. Nuclear Regulatory Commission Mr. David Stewart-Smith State of Oregon Department of Energy r
i.
l Mr. R. C. Barr
+
l NRC Resident Inspector l.
Trojan Nuclear Plant l
9003220038 90031b
+
PDR ADOCK 03000344 P
FDC
]
l
\\
121 S.W. Salmon Street, Portland, Oregon 97204,503/464-8897
j Trojan Nucacar Plant Document Control Desk Docket 50-344 March 15, 1990 License NPF-1 Attachment Page 1 of 3 PORTLAND GENERAL ELECTRIC COMPANY (PGE) RESOLUTION OF UNRESOLVED SAFETY ISSUE A-47, " SAFETY IMPLICATION OF CONTROL SYSTEMS IN LWR NUCLEAR POWER PLANTS" Generic Letter 89-19 defines three steam generator overfill protection designs for Westinghouse-Designc$ Pressurized Water Reactor (PWR) Plants.
The Trojan Nuclear Plant is considered to be included in the Group I plant design as the Trojan steam generator (S/G) overfill protection feature includes all the design requirements recommended for Group I plants. Steam Generator overfill protection at Trojan is provided by an Engineered Safety Feature Actuation System (ESFAS) Interlock (P-14),
which has ESFAS functions of Turbine Trip and Main Feedwater (MFW) isolation and a non-ESFAS function of tripping both MFW pumps.
Therefore, the Trojan Nuclear Plant will not require any modifications to meet the design recommendations of Generic Letter 89-19.
The Trojan S/G overfill protection feature includes the recommended sufficient separation of the control and protection functions such that a fire is not likely to affect both control and protection systems.
In addition, Plant procedures include requirements to periodically verify operability of the ESFAS functions. Procedures are scheduled to be revised to include periodic verification of the non-ESFAS function (MFW pump trip).
In addition, the MFW pump trip function is scheduled to be verified during the 1990 refueling outage. The Trojan Technical Specifications require verification of the MFW isolation function as it is an ESFAS function. However, the MFW pump trip function is not an ESFAS function and is not required by technical specification to be tested.
Detail information concerning Generic Letter 89-19 specific items are discussed below.
DESIGN REOUIREMENTS The generic letter defines a Group I Plant as having a S/G overfill protection system which initiates on a steam generator high-water-level signal based on a 2-out-of-3 initiating logic which is safety grade but uses one out of the three channels for both control and protection.
The system isolates MFW by closing the MFW isolation valvos and tripping the MFW pumps.
The Trojan Nuclear Plant is included in the Group I design group for the following reasons:
1.
Trojan S/G overfill protection uses 2-out-of-3 initiating logic Which is safety grade but uses one out of the three channels for both control and protection.
i*
Trojan Nuclear Plant Document Control Desk Docket 50-344 March 15, 1990 License WPF-1 Attachment Page 2 of 3 2.
Trojan S/G overfill protection isolates MFW by tripping both MFW pumps, tripping the Turbine and generating a feed-water isolation i
signal (FWIS) which closes the MFW regulating valves, MFW bypass valves, MFW isolation valves and the MFW isolation bypass valves.
1 SEPARATION OF CONTROL AND PROTECTION I
The NRC has concluded that the Grou-; I design is acceptable, provided that the S/G overfill protection system is sufficiently separate from the control portion of the MFW control system so that it is not powered from the same power source, not located in the same cabinet, and not routed so that a fire is likely to affect both systems.
A review of the Trojan S/G overfill protection feature was conducted to verify that Generic Letter 89-19 recommendations for Westinghouse-designed Group I power plants are included in the Trojan S/G overfill protection system.
The Trojan Nuclear Plant is considered to have a sufficient S/G overfill protection feature for the following reasons that were verified during the above referenced review:
1.
The protection function equipment is supplied from safety-related power supplies and the control function equipment is supplied from non safety-related power supplies, i
2.
S/G 1evel signals are processed in the safety-related Westinghouse 7100 Process Instrument Racks.
The control portion of the S/G 1evel signal is routed to the 7100 Process Control Racks for development of the MFW control signals. The control cabinets are i
physically different and separate cabinets from the protection l
cabinets.
l o
3.
Cables for reactor protection signals are routed in channelized cable l
trays and conduit. This affords the standard safety-related fire separation that is afforded to all other safety-related protection signals (per the separation criteria specified in Section 8.3.1.4 of the Trojan Final Safety Analysis Report).
The S/G 1evel control i
l signals are routed in non-channelized cable tray and conduit.
Therefore, the Trojan S/G overfill protection feature is considered to include all the Generic Letter 89-19 recommendations for Westinghouse-designed Group I PWR plants.
l l
PROCEDURES AND TECHNICAL SPECIFICATIONS l
The NRC has concluded that the Group I design is acceptable, provided L
that the overfill protection system procedures and Technical l
i 4
i J
Trojan Nuclear Plant Document Control Desk Docket 50-344 March 15, 1990 License NPF-1 Attachment 1
Page 3 of 3 i
Specifications include requirements to periodically verify operability of this system.
Existing Trojan surveillance procedures (Periodic Instrumentation and Control Tests) include testing the ESFAS portion of the steam generator overfill protection feature (i.e.
Turbine Trip and MFW isolation).
Procedures for periodically testing the NFW pump trip portion of the overfill-protection feature are scheduled to be completed by September 30, 1990.
The MFW pump trip functional test using approved i
maintenance work instructions is scheduled to be conducted prior to return to power operation from the 1990 refueling outage and included in future channel functional tests of the S/G P-14 Interlock.
CONCLUSION The Trojan Nuclear Plant S/G overfill protection feature design meets Generic Letter 89-19 criteria.
Therefore, no design changes are necessary or scheduled to meet Generic Letter 89-19 recommendations.
In an effort to meet Generic Letter 89-19 recommendations for periodic operability verification of S/G overfill protection, PCE will revise procedures to include periodic verification of the MFW pump trip function. The procedures will be revised by September 30, 1990 and the r
MFW pump trip function will be tested prior to return te power operation from the 1990 refueling outage using approved maintenance work inst ructions.
In addition, the NFW pump trip testing will be incorporated into future channel functional tests of the P-14 Interlock.
RNS/bsh 4442W.0390 i
m