ML20155C255
| ML20155C255 | |
| Person / Time | |
|---|---|
| Site: | Trojan File:Portland General Electric icon.png |
| Issue date: | 10/03/1988 |
| From: | Cockfield D PORTLAND GENERAL ELECTRIC CO. |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| NUDOCS 8810070318 | |
| Download: ML20155C255 (4) | |
Text
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t-Portland GeneralElectricCorim r
El:
David W. Cockfield Vice President. Nuclear October 3, 1988 Trcjan Nuclear Plant Docket 50-344 Licenso NPF-I U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington DC 20555
Dear Sir:
Final Ronponse to the Nuclear Regulatory Commission (NRC) Safety Evaluation of WCAP-10858, "Anticipated Transient Without Scram (ATWS)
MitigatJn LS stem Actuation Circuitry (AMSAC) 03neric DesignJ ackage" y
References:
1.
NRC Letter to Portland Ceneral E1cetric Company (PCE) Dated September 23, 1986, Transmitting Safety Evaluation of Tople 1 Report (L' CAP-10858), "AMSAC Ceneric Design Package'.
2.
PCR Letter to NRC Dated October 29, 1986, "Rerponse to NRC Saf=6y Evaluation on AMSAC Ceneric Design Packago".
3.
PCE Letter to NRC Dated October 30, 1987 "Plant-Specific Response to the NRC Safety Evaluation of WCAP-10858, "Anticipated Transient Without Scram ( AWS) Mitigating System Actuation Circuitry ( AMSAC)
Ceneric Design Packago".
4.
PCE to NRC Letter Dated April 13, 1988 "Supplemental Responso to the Nuc1 car Regulatory Commission (NRC) Safety Evaluation of WCAP-10858, "hiticipated Transient Without Scram (ATWS) Mitignting System actuation Circuitry (AMSAC) Cereric Design Package".
5.
PCE to NRC Conference Call Dated Juno 2, 1988. to this letter transmits the final responso for Plant-specific design features related to AMSAC as committed to in References 4 and 5.
In particular, the responso includes information on testing of the s
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o N Geritrd MCorigxurf Docement Control Desk October 3, 1988 Eago 2 isolation relayg, design details for the logic power supplies and informa-tion doccribing the actual timo delay sottings for AMSAC actuation.
It is PCE's understanding, based on Reference 5, that the submittal of this information will satlofy all NRC concerns regarding the AMSAC design for i
the Trojan Nucioar Plant and that additional responses from PCE are not requirod.
I Sincornly, i
F Attachment c
Mr. John B. Martin Regional Administrator, Region V l
U.S. Nuclear Regulatory Commission l
Mr. William T. Dixon
-1 State of Oregon 1
Department of Energy Mr. R. C. Barr NRC Resident Inspector l
Trojan Nuclear Plant l
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e Trojan Nuclear Plant Document Control Desk Docket 50-344 j
License NPF-1 October 3, 1983 Page 1 of 2 Final Response to the j
Nuclear Regulatory Commission (NRC) Safety Evaluation' of WCAP-10058, "Anticipated Transient Without Scram (ATWS)
Mitimating System Actuation circuitry (AMSAC) Ceneric. Design Peckste" Portland General Electric Company's (PCE's) response to remaining NRC concerns are as follows:
1.
NRC Concern - D!versity The test data for all isolation devices should be carefully reviewod by PCE for compliance with Appendix A of the NRC Safety Evaluation.
It is requested that all test results, and PCE's review of the test results, be maintained onsite and available for audit.
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PCE Aesponse - Diversity l
The purchase specifications f or the isolation devices include all the test requirements delineated in Appendix A of the NRC Safety I
Evaluation.
The test results will not be available until December 1, 1988. PCE will review all test data upon receipt. A copy of the I
test results and documented evaluations of the test data will be maintained with the design package and will be available for audit.
I 2.
NRC Concern - Logic Power Supplies I
f PCE had planned on providing a diesel-backed power source to optimize j
reliability, taking credit for system protective design features to
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preclude common mode failures from affecting both the reactor protec-tion system and AMSAC. The NRC's interpretation of the AMSAC rule is that the reactor protection system and AMSAC power supplies must be i
j independent and cannot be tied to the same 480-Vac buses.
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PCE Response - Logie Power Supplies l
l PCE has selected non-1E lighting Panel L-29 as the new source of f
4 power to AMSAC. This panel receives its power from 480-Vac Bus B-29
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which receives its power from non-1E 4160-Vac Bus A-5.
Bus A-5 is l
not normally diesel-backed and is completely independent from any 4
j reactor protection system power sourco, j
i 3.
NRC Concern - Time-Delay Settints j
l The NRC requested the time-delay settinge to be used for delaying the AMSAC signal upon reaching a low-low steam generator level, and i
maintaining the C-20 permissive signal to avoid blocking AMSAC before
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it can perform its functions in the event of a turbine trip.
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Trojan Nuclear Plant Document control Desk Docket 50-344 License NPF-1 October 3, 1988 Page 2 of 2 l
PCE Response - Time-Delay Settings PGE has determined that the low-low steam generator level actuation time delay will be set at 25 seconds. This value provides sufficient time for normal reactor protection system initiation of auxiliary feedwater and turbine trip, while assuring that in the event of an ATWS, the turbine is tripped within 30 seconds and auxiliary foodwater is initiated within 90 seconds.
The C-20 permissive time delay will be set for 160 seconds, which is consistent with the recommendations of WCAP-10858.
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