ML13311B193
| ML13311B193 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 11/14/2013 |
| From: | Ellen Brown Plant Licensing Branch III |
| To: | Lieb R FirstEnergy Nuclear Operating Co |
| Eva Brown, NRR/DORL 415-2315 | |
| References | |
| L-13-040, TAC MF0536 | |
| Download: ML13311B193 (5) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 Mr. Raymond A. Lieb Site Vice President FirstEnergy Nuclear Operating Company Mail Stop A-DB-3080 5501 North State, Route 2 Oak Harbor, OH 43449-9760 November 14, 2013
SUBJECT:
DAVIS-BESSE NUCLEAR POWER STATION, UNIT NO. 1 -REQUEST FOR ADDITIONAL INFORMATION RELATED TO STEAM GENERATOR INVENTORY CHANGE (TAC NO. MF0536) (L-13-040)
Dear Mr. Lieb:
By letter dated January 18, 2013, as supplemented by a letter dated September 27, 2013 (Agencywide Documents Access and Management System (ADAMS) Accession Nos.
ML13018A350 and ML13273A356), FirstEnergy Nuclear Operating Company (FENOC, the licensee) submitted a license amendment request (LAR) for the Davis-Besse Nuclear Power Station, Unit No. 1. The request is to revise Technical Specification (TS) 3.4.17, "Steam Generator (SG) Tube Integrity," TS 3.7.18, "Steam Generator Level," TS 5.5.8, "Steam Generator Program," and TS 5.6.6, "Steam Generator Tube (SGTR) Inspection Report." The revision of these TSs was requested to support replacement of the original SGs during a refueling outage in April2014. The proposed changes to TSs3.4.17, 5.5.8, and 5.6.6, include adoption of the program improvements in Technical Specifications Task Force (TSTF)-510, Revision 2, "Revision to Steam Generator Program inspection Frequencies and Tube Sample Selection," which was approved by the U.S. Nuclear Regulatory Commission (NRC) on October 27, 2011.
The NRC staff is reviewing your 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 your staff on November 4, 2013, it was agreed that you would provide a response within 30 days from the date of this letter.
The NRC staff considers that timely responses to requests for additional information help ensure sufficient time is available for staff review and contribute toward the NRC's 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.
Docket No. 50-346
Enclosure:
Request for Additional Information cc w/encl: Distribution via Listserv Sincerely, IRA/
Eva A Brown, Senior Project Manager Plant Licensing Branch 111-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation
REQUEST FOR ADDITIONAL INFORMATION STEAM GENERA TOR REPLACEMENT DAVIS-BESSE NUCLEAR POWER STATION. UNIT NO.1 FIRSTENERGY NUCLEAR OPERATING COMPANY DOCKET NO. 50-346 TAC NO. MF0536
- 1.
The NRC staff is concerned that the steam generator (SG) inventory characteristics may change as a result of the proposed changes or the related modifications. The concerned is based on the proposed revision to Technical Specification (TS) Figure 3.7.18-1, which would require the operating range to remain lower than the existing limit, even though the revised TS BASES included with the January 18, 2013, submittal, states that the initial inventory in the SG will remain the same. The TS BASES included for information in Attachment 3 to the submittal, the licensee indicates that the requirements contained in TS limiting condition for operations (LCO) 3.7.18, "Steam Generator [SG] Level," are based
... primarily [emphasis added] on preserving the initial condition assumptions for the steam generator inventory used in the main steam line break (MSLB) accident analysis."
Similarly, the Applicable Safety Analyses from the submittal section states,
[t]he most limiting [emphasis added] Design Basis Accident [DBA]
that would be affected by steam generator operating level is a main steam line failure.
The proposed revision toTS Figure 3.7.18 would modify TS LCO 3.7.18.a to specify the SG operate range level as a revised function of main steam superheat.
Since the emphasized language in the TS BASES suggests that the LCO requirements may not be exclusively related to the MSLB analyses, address whether the process variables, design features, and/or operating restrictions controlled by TS LCO 3.7.18.a are initial conditions for other design basis accident or transient analyses that either assume the failure of or present a challenge to the integrity of a fission product barrier.
- a. In particular, state whether operation at the limit prescribed by TS LCO 3. 7.18.a is assumed in any of the feedwater line break, SG tube rupture, or emergency core cooling system evaluation/loss-of-coolant-accident analyses.
Enclosure
- b.
If the operation at the limit prescribed by LCO 3. 7.18.a is assumed in the DBA listed above, explain whether the proposed LCO would ensure that plant operation remains bounded by the existing safety analyses.
- c.
If it is not, provide a brief summary of, and the basis for, the selected secondary side initial conditions.
- 2.
Regarding the MSLB analyses, the TS BASES forTS LCO 3. 7.18 indicate that Figure 3. 7.18-1 is based on maintaining inventory <56,000 pounds-mass (Ibm), which ensures that the MSLB analysis is bounding "considering all plant effects (e.g., steam superheat and downcomer voiding)."
Explain how limiting the mass present in the SG ensures that the MSLB analysis remains bounding in consideration of other secondary side thermal-hydraulic phenomena, including not only steam superheat and downcomer voiding, but also the axial void profile on the secondary side of the tube bundle region. These phenomena contribute to the predicted performance of the plant during a postulated transient. For example, explain why an MSLB inside containment would not discharge more energy to the containment if initiated with a higher superheat level, despite that more steam and less mass may have initially been present in the steam generator (i.e., at a condition to the right of, and below, the proposed limit line).
ML13311B193 OFFICE LPL3-2/PM LPL3-2/LA NAME EBrown SRohrer DATE 11/13/13 11/12/13 Sincerely, IRA!
Eva A. Brown, Senior Project Manager Plant Licensing Branch 111-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation RidsNrrDoriDpr Resource RidsAcrsAcnw_MaiiCTR Resource RidsRgn3MaiiCenter Resource RidsNrrLASRohrer Resource RidsNrrDssSrxb, Resource RGrover, DSS KKarwoski, DE SRXB/BC LPL3-2/BC CJackson TTate 11/1/13 11/14/13