ML110260320
| ML110260320 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 02/04/2011 |
| From: | Ellen Brown Plant Licensing Branch III |
| To: | Pacilio M Exelon Nuclear |
| Brown Eva, NRR/DLPM, 415-2315 | |
| References | |
| TAC ME4844, TAC ME4845, RS-10-021 | |
| Download: ML110260320 (5) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555*0001 February 4, 2011 Mr. Michael J. Pacilio President and Chief Nuclear Officer Exelon Nuclear 4300 Winfield Road Warrenville, IL 60555
SUBJECT:
DRESDEN NUCLEAR POWER STATION, UNITS 2 AND 3 - REQUEST FOR ADDITIONAL INFORMATION RELATED TO ELIMINATION OF MAIN STEAM ISOLATION VALVE CLOSURE AND LOW CONDENSER SCRAM (TAC NOS. ME4844 AND ME4845) (RS-10-021)
Dear Mr. Pacilio:
By letter to the Nuclear Regulatory Commission (NRC) dated October 14, 2010 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML102800148), Exelon Generation Company, LLC submitted a request to revise Technical Specification (TS) Table 3.3.1.1 to eliminate Functions 5 and 10 from TS Table 3.3.1.1-1, delete footnote (c) from that table, and rename the footnote (d) to (c). These revisions would eliminate the requirement for a reactor scram, if vessel pressure is greater than or equal to 600 pounds per square inch gage, with the reactor mode switch in startup and the main steam isolation valves closed or with a main turbine condenser vacuum low condition for the Dresden Nuclear Power Station, Units 2 and 3.
The NRC staff has reviewed the October 14, 2010, submittal and has determined that additional information is required to complete the review. The specific information requested is addressed in the enclosure to this letter.
During a discussion with Mr. Timothy Byam of your staff on February 1, 2011, it was agreed that you would provide a response within 30 days from the date of this letter. Please note that if you do not respond to this letter within the prescribed response time or provide an acceptable alternate date in writing, we may reject your application for amendment under the provisions of Title 10 of the Code of Federal Regulations (10 CFR), Section 2.108.
M. Pacilio
- 2 The NRC staff considers that timely responses to requests for additional information help ensure sufficient time is available for NRC staff review and contribute toward the NRC goal of efficient and effective use of staff resources. If circumstances result in the need to revise the requested response date, please contact me at (301) 415-2315.
Sincerely, IRA!
Eva A. Brown, Senior Project Manager Plant Licensing Branch 111-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-237 and 50-249
Enclosure:
Request for Additional Information cc w/encl: Distribution via Listserv
REQUEST FOR ADDITIONAL INFORMATION ELIMINATION OF MAIN STEAM ISOLATION VALVE CLOSURE AND LOW CONDENSER VACUUM SCRAM DURING STARTUP EXELON GENERATION COMPANY, LLC DRESDEN NUCLEAR POWER STATION, UNITS 2 AND 3 DOCKET NOS. 50-237 AND 50-249
- 1.
In General Electric Nuclear Energy Service Information Letter (SIL) 107, "Increasing Flexibility of Reactor Startups," dated October 31, 1974 (SIL-1 07), section titled, "Recommended Action" for boiling water reactor (BWR)/1, 2 and 3 plants, it stated, Any utility with a plant in this group who wishes to further explore the possibility of "bottled-up" startups should contact its normal General Electric service representative for a quotation conceming engineering analysis and testing.
It is not clearfrom the language used in SIL-107 that its recommendation gives the licensee a choice between performing either an engineering analysis or a test, as was suggested by the licensee in its submittal dated October 4, 2010 (the submittal). Rather, the SIL appears to recommend the performance both testing and analysis to justify "bottled-up" startups for BWRl1, 2, and 3 plants. Explain why performing an engineering analysis alone is sufficient justification for "bottled-up" startups for Dresden.
- 2.
In 1974, when the tests were conducted at the Browns Ferry Nuclear (BFN) plant, the BFN plant was not operating within the Maximum Extended Load Line Limit Analysis (MELLLA) domain and at Extended Power Uprate (EPU). Whereas, Dresden is currently operating at EPU within MELLLA domain. Given significant differences between the operating condition and design of the two plants, please justify how the test data obtained for BFN is applicable for comparison to Dresden.
- 3.
In Section 1.1 of the NRC staff's safety evaluation for NEDE-32906P "Migration to TRACG04/PANAC11 from TRACG02/PANAC10 for TRACG AOO and ATWS
[anticipated transient without scram] Overpressure Transients," dated July 10, 2009 it states:
... the NRC staff review is limited to the application of the methodology to AOO [abnormal operating occurrence], ASME overpressure, and ATWS overpressure transient analyses.
Therefore, the NRC staff approval of the subject L TR does not constitute generic approval of the TRACG04/PANAC11 methodology to all transient applications.
ENCLOSURE
-2 Since the transient analyzed in Attachment 4 of the submittal is not classified as a typical AOO, and that the NRC staff's approval of the TRACG04/PANAC11 methodology does not constitute generic approval for all transient applications, provide detailed technical justification regarding applicability of the methodology to support elimination of main steam isolation valve closure and low condenser vacuum scram functions during startup mode for Dresden.
- 4.
As NEDE-32906P-A (Supplement 3) does not provide full justification for each specific individual plant application for TRACG, provide the following information:
- a.
The specific guidelines used to develop the plant-specific nodalization. Any deviations from the reference plant should be described and defended, and
- b.
Sensitivity studies showing the effects of any plant-specific parameters which have been identified as being outside the range used in demonstrating acceptable code performance deviation.
M. Pacilio
- 2 The NRC staff considers that timely responses to requests for additional information help ensure sufficient time is available for NRC staff review and contribute toward the NRC goal of efficient and effective use of staff resources. If circumstances result in the need to revise the requested response date, please contact me at (301) 415-2315.
Sincerely, IRA!
Eva A. Brown, Senior Project Manager Plant licensing Branch 111-2 Division of Operating Reactor licensing Office of Nuclear Reactor Regulation Docket Nos. 50-237 and 50-249
Enclosure:
Request for Additional Information cc w/encl: Distribution via listserv DISTRIBUTION:
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