ML16342E021
| ML16342E021 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 03/16/1998 |
| From: | Steven Bloom NRC (Affiliation Not Assigned) |
| To: | Rueger G PACIFIC GAS & ELECTRIC CO. |
| References | |
| TAC-MA0743, TAC-MA0744, TAC-MA743, TAC-MA744, NUDOCS 9803200129 | |
| Download: ML16342E021 (8) | |
Text
Haunch 16, 1998 Mr. Gregory M. Rueger, Senior Vice President
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and General Manager Pacific Gas and Electric Company Nuclear Power Generation N9B P. O. Box 770000 San Francisco, California 94177
SUBJECT:
REQUEST FOR ADDITIONALINFORMATION-PROPOSED LICENSE AMENDMENTREGARDING OFFSITE ELECTRICALPOWER SYSTEM, IMPROVEMENTS (TAC NOS. MA0743 AND MA0744)
Dear Mr. Rueger:
By letter dated January 14, 1998, Pacific Gas and Electric Company (PGB E) submitted License Amendment Request 98-01 supporting modiTications made to the offsite electrical power system associated with the Diablo Canyon Power Plant, Unit Nos.
1 and 2. Based on initial review, the staff has identified additional technical information required to complete the evaluation of your request.
The staff's request for additional information is enclosed.
Please submit your response within 60 days of receipt of this letter.
Sincerely, Original Signed By Steven D. Bloom, Project Manager Project Directorate IV-2 Divisio'n of Reactor Projects III/IV Office of Nuclear Reactor Regulation Docket Nos. 50-275 and 50-323
Enclosure:
Request for Additional Information cc w/encl: See next page Document Name:
DC MA074.DPL DISTRIBUTION:
Docket
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Mr. Gregory M. Rueger March 16, 1998 cc w/encl:
NRC Resident Inspector Diablo Canyon Nuclear Power Plant c/o U.S. Nuclear Regulatory Commission P. O. Box 369 Avila Beach, California 93424 Dr. Richard Ferguson, Energy Chair Sierra Club California 1100 11th Street, Suite 311 Sacramento, California 95814 Ms. Nancy Culver San Luis Obispo Mothers for Peace P. O. Box 164 Pismo.Beach, California 93448 Chairman San Luis Obispo County Board of Supervisors Room 370 County Government Center San Luis Obispo, California 93408 Mr. Truman Burns Nlr. Robert Kinosian California Public Utilities Commission 505 Van Ness, Room 4102 San Francisco, California 94102 Mr. Steve Hsu Radiologic Health Branch State Department of Health Services Post Office Box 942732 Sacramento, California 94232 Diablo Canyon Independent Safety Committee ATTN: Robert R. Wellington, Esq.
Legal Counsel 857 Cass Street, Suite D Monterey, California 93940 Regional Administrator, Region IV U.S. Nuclear Regulatory Commission Harris Tower 8 Pavillion 611 Ryan Plaza Drive, Suite 400 Arlington, Texas 76011-8064 Christopher J. Warner, Esq.
Pacific Gas 8 Electric Company Post Office Box 7442 San Francisco, California 94120 Mr. Robert P. Powers Vice President and Plant Manager Diablo Canyon Nuclear Power Plant P. O. Box 56 Avila Beach, California 93424 Telegram-Tribune ATTN: Managing Editor 1321 Johnson Avenue P.O. Box 112 San Luis Obispo, California 93406
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1.
The Diablo Canyon licensing basis requires the offsite system to have sufficient capacity and capability to supply the necessary voltage to safety system loads following the occurrence of two transmission network contingencies."~'onfirm this.
2.
Revision 11 of the Diablo Canyon Final Safety Analysis Report Update (FSAR) notes that procedurally controlled compensatory measures may be required to meet the licensing basis described above (as part of question 1) for certain line outages (i.e.,
Morro Bay-Diablo Canyon, Diablo Canyon-Mesa, or Morro Bay-Mesa). After implementation of the 230 kV system improvements, it is the staffs understanding that these compensatory measures will no longer be needed to meet the Diablo Canyon licensing basis.
Confirm this.
'I 3.
For operation prior to the installation of capacitor banks, provide results of analyses that demonstrate that sufficient capacity and capability willbe available from the transmission network to supply the necessary voltage to safety system loads following any one transmission contingency'ssuming the second contingency defined below.'.
For operation after the installation of capacitor banks, provide results of analyses that demonstrate that sufficient capacity and capability willbe available from the transmission network to supply the necessary voltage to safety system loads following any one transmission contingency'ssuming the second contingency defined below.'.
Describe the contractual requirements of the independent system operator and PG&E/plant procedural requirements which assure compliance with the licensing basis requirements (described as part of question 1 above) for the Diablo Canyon offsite system.
'The first transmission network contingency is defined as the loss of the worst case (most heavily loaded) transmission line, switchyard bus, capacitor bank, or generating unit connected to (or associated with) the transmission network, assuming the worst case summer and/or winter expected loading or operating configuration of the transmission network. Five exceptions to this contingency are explicitly defined on page 8.2-3 of Section 8.2.2 of Revision 11 of the FSAR.
'The second contingency is defined as the trip of one of the two Diablo Canyon units following a loss of coolant accident and trip of the second unit 30 seconds following trip of the accident unit or, ifmore limiting, assuming one unit operating at 100 percent power with a loss of coolant accident trip.
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Based on information presented in the January 14, 1998, amendment request, the staff understands that following the bounding transmission network contingency (i.e., loss of the worst case transmission line), stability analysis demonstrates that dependence on the toad tap changer to maintain voltage is not required to assure the continued immediate availability of offsite power following a loss of coolant accident.
In addition, operation of the load tap changer to boost voltage is not required to assure reset of first or second levels of undervoltage protection.
Confirm this.
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