ML032170679
| ML032170679 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 08/05/2003 |
| From: | Nerses V NRC/NRR/DLPM/LPD1 |
| To: | Clifford J NRC/NRR/DLPM/LPD1 |
| Nerses V, NRR//DLPM, 415-1484 | |
| References | |
| TAC MB6166 | |
| Download: ML032170679 (4) | |
Text
August 5, 2003 MEMORANDUM TO: James W. Clifford, Chief, Section 2 Project Directorate I Division of Licensing Project Management Office of Nuclear Reactor Regulation FROM:
Victor Nerses, Sr. Project Manager, Section 2
/RA/
Project Directorate I Division of Licensing Project Management Office of Nuclear Reactor Regulation
SUBJECT:
MILLSTONE POWER STATION, UNIT NO. 3, FACSIMILE TRANSMISSION, DRAFT REQUEST FOR ADDITIONAL INFORMATION (RAI) TO BE DISCUSSED IN AN UPCOMING CONFERENCE CALL (TAC NO. MB6166)
The attached draft RAI was transmitted by facsimile on August 5, 2003, to Mr. Ravi Joshi, Dominion Nuclear Connecticut, Inc. (licensee). This draft RAI was transmitted to facilitate the technical review being conducted by NRR and to support a conference call with the licensee to discuss the RAI. The RAI was related to the licensees submittal dated August 7, 2002, concerning Limiting Safety System Settings. Review of the RAI would allow the licensee to determine and agree upon a schedule to respond to the RAI. This memorandum and the attachment do not convey or represent an NRC staff position regarding the licensees request.
Docket No. 50-423
Attachment:
Draft RAI
August 5, 2003 MEMORANDUM TO: James W. Clifford, Chief, Section 2 Project Directorate I Division of Licensing Project Management Office of Nuclear Reactor Regulation FROM:
Victor Nerses, Sr. Project Manager, Section 2
/RA/
Project Directorate I Division of Licensing Project Management Office of Nuclear Reactor Regulation
SUBJECT:
MILLSTONE POWER STATION, UNIT NO. 3, FACSIMILE TRANSMISSION, DRAFT REQUEST FOR ADDITIONAL INFORMATION (RAI) TO BE DISCUSSED IN AN UPCOMING CONFERENCE CALL (TAC NO. MB6166)
The attached draft RAI was transmitted by facsimile on August 5, 2003, to Mr. Ravi Joshi, Dominion Nuclear Connecticut, Inc. (licensee). This draft RAI was transmitted to facilitate the technical review being conducted by NRR and to support a conference call with the licensee to discuss the RAI. The RAI was related to the licensees submittal dated August 7, 2002, concerning Limiting Safety System Settings. Review of the RAI would allow the licensee to determine and agree upon a schedule to respond to the RAI. This memorandum and the attachment do not convey or represent an NRC staff position regarding the licensees request.
Docket No. 50-423
Attachment:
Draft RAI DISTRIBUTION PUBLIC J. Clifford V. Nerses JKnox PDI-2 Reading Accession Number: ML032170679 *See Previous Concurrence OFFICE PDI-2/PM EEIB/SC NAME VNerses RJenkins
- DATE 08/05/03 08/05/2003 OFFICIAL RECORD COPY
DRAFT REQUEST FOR ADDITIONAL INFORMATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION FACILITY OPERATING LICENSE NO. NPF-49 DOMINION NUCLEAR CONNECTICUT, INC MILLSTONE POWER STATION, UNIT NO. 3 DOCKET NO. 50-423 (TAC NO. MB6166)
By letter dated August 7, 2002, Dominion Nuclear Connecticut, Inc. (the licensee) submitted a proposed amendment to the Technical Specifications (TS) for Millstone Unit 3. The proposed amendment would modify selected Limiting Safety System Settings.
The Nuclear Regulatory Commission (NRC) staff has reviewed the information the licensee provided that supports the proposed changes to the TS. In order for the staff to complete its evaluation, the following additional information is requested:
1.
As part of Millstones design, the emergency generator load sequencer (EGLS) (or the loss of power instrumentation through the EGLS) in response to an accident signal (without loss of power), delays the start of the containment recirculation pumps. This delayed start of the containment recirculation pumps, pursuant to General Design Criterion (GDC 17), supports the availability of sufficient capacity and capability of the offsite system circuit (assuming the onsite system is not functioning and single failure of one load group) to assure the core is cooled and containment integrity and other vital functions are maintained in the event of postulated accidents. Explain/justify either why this delayed start of the containment recirculation pumps which assures sufficient capacity and capability of the offsite system is not a design basis requirement for the Millstone plant as conveyed by the Millstone FSAR or why, when this design basis requirement is not met, explicit Technical Specification (TS) Limiting Condition for Operation (LCO) requirements are not required.
2.
As part of Millstones design, the onsite systems, in response to an actuation signal from the loss of power instrumentation (with or without an accident signal), trips the offsite power supply breaker to the load group. Tripping the supply breaker isolates (and thus protects) the load group from the degraded and transient voltage conditions that may exist on the offsite power supply during a loss of offsite power event. This protection, in accordance with the requirements of GDC 17, minimizes the probability of losing electric power from any of the remaining supplies as a result of, or coincident with, the loss of power generated by the nuclear power unit, the loss of power from the transmission network, or the loss of power from the onsite electric power supplies. This supports the availability of sufficient capacity and capability of the load group when needed (assuming the offsite system is not functioning and single failure of one onsite power source or load group) to assure fuel design limits and design conditions of the reactor coolant boundary are not exceeded as a result of anticipated operational occurrences.
Explain/justify either why the opening of the offsite power supply breaker which assures
sufficient capacity and capability of the load group is not a design basis requirement for the Millstone plant as conveyed by the Millstone FSAR or why, when this design basis requirement is not met, explicit TS LCO requirements are not required.
3.
Provide results of a risk evaluation for the proposed 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> LCO assuming loss and non-recovery of one of two divisions including loss and non-recovery of the divisions associated dc systems after two hours or when the battery would be depleted. Justify any deviations from guidelines of RG 1.174 and 1.177.
4.
Is there any reason why the proposed TS requires that the EDG be declared inoperable in the case where 2 out of 4 channels are inoperable leaving 2 operable channels which still permits the Loss of Voltage instrumentation to perform its intended safety function (i.e., provide coincident logic signals to emergency generator load sequencer)?