L-MT-14-025, Extension Request Regarding Flooding Hazard Reevaluation Report Required by NRC Request for Information Pursuant to Title 10 of the Code of Federal Regulations 50.54(f) Regarding Recommendation 2.1, Flooding, of the Near-Term Task Force.
| ML14071A448 | |
| Person / Time | |
|---|---|
| Site: | Monticello  (DPR-022) |
| Issue date: | 03/11/2014 |
| From: | Fili K Northern States Power Co, Xcel Energy |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| L-MT-14-025 | |
| Download: ML14071A448 (8) | |
Text
Xcel Energy March 11, 2014 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Monticello Nuclear Generating Plant Docket No. 50-263 Renewed Facility Operating License No. DPR-22 Monticello Nuclear Generating Plant 2807 W County Road 75 Monticello, MN 55362 L-MT-14-025 10 CFR 50.54(f)
Extension Request Regarding the Flooding Hazard Reevaluation Report Required by NRC Request for Information Pursuant to Title 10 of the Code of Federal Regulations 50.54{f) Regarding Recommendation 2.1, Flooding, of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident
References:
- 1.
NRC Letter, "Requestfor Information Pursuant to Title 10 of the Code of Federal Regulations 50.54(f) Regarding Recommendations 2.1, 2.3, and 9.3, of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident," dated March 12, 2012 (ADAMS Accession No. ML12053A340).
- 2.
NRC Letter, "Prioritization of Response Due Dates for Request for Information Pursuant to Title 10 of the Code of Federal Regulations 50.54(f) Regarding Flooding Hazard Reevaluations for Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident," dated May 11, 2012 (ADAMS Accession No. ML12097A509).
- 3.
NRC Letter, "Supplemental Information Related to Request for Information Pursuant to Title 10 of the Code of Federal Regulations 50.54(f) Regarding Flooding Hazard Reevaluations for Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident," dated March 1, 2013 (ADAMS Accession No. ML13044A561).
On March 12, 2012, the Nuclear Regulatory Commission (NRC) Staff issued the Reference 1 letter to all NRC power reactor licensees and holders of construction permits in active or deferred status. Enclosure 2 of Reference 1 contains specific Requested Actions, Requested Information, and Required Responses associated with Near-Term Task Force (NTTF) Recommendation 2.1 for flooding hazards. Enclosure 2
Document Control Desk Page 2 of Reference 1 directed reevaluation of flooding hazards at sites and indicated that a Hazard Reevaluation Report (HRR) would be due within one to three years from the date of the Reference 1 letter. On May 11, 2012, the NRC issued the Reference 2 letter that contained the NRC's prioritization plan and due dates for licensees' submittal of HRRs. The Monticello Nuclear Generating Plant (MNGP), operated by Northern States Power Company, a Minnesota corporation (NSPM), d/b/a Xcel Energy, was identified as a Category 2 site in Reference 2 and was required to submit the HRR by March 12, 2014.
In Reference 3, the NRC provided supplemental information stating incomplete HRRs that only contain an analysis of some flooding hazard mechanisms would not be of substantive benefit for staff review and would not be acceptable. Therefore, Reference 3 recommends licensees not submit partial reports, but instead submit an extension request.
The purpose of this letter is to request an extension of the March 12, 2014 due date for submittal of the HRR for the MNGP. The Enclosure to this letter contains the extension request. The extension request was prepared using the guidance in Reference 3 and includes the reasons for the delay, a proposed schedule for the submittal of a complete HRR, and the basis for acceptability of the revised schedule.
If there are any questions or if additional information is needed, please contact Jennie Wike, Licensing Engineer, at 612-330-5788.
Summary of Commitments This letter makes one new commitment and makes no revisions to existing commitments.
NSPM will submit the required flood HRR for MNGP within 10 months of receiving the US Army Corps of Engineers' final information.
I declare under penalty of perjury that the foregoing is true and correct.
Karen D. Fili Site Vice President, Monticello Nuclear Generating Plant Northern States Power Company - Minnesota
Document Control Desk Page 3 cc:
Administrator, Region Ill, USNRC Director of Nuclear Reactor Regulation (NRR), USNRC NRR Project Manager, Monticello Nuclear Generating Plant, USNRC Senior Resident Inspector, Monticello Nuclear Generating Plant, USNRC
ENCLOSURE MONTICELLO NUCLEAR GENERATING PLANT Extension Request Regarding the Flooding Hazard Reevaluation Report Required by NRC Request for Information Pursuant to Title 10 of the Code of Federal Regulations 50.54(f) Regarding Recommendation 2.1. Flooding. of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident Request For Extension: Reason for the Delay, Proposed Schedule, and Basis for Acceptability Page 1 of 5
Enclosure NSPM Request For Extension 1.0 Introduction On March 12, 2012, the Nuclear Regulatory Commission (NRC) Staff issued the Reference 1 letter to all NRC power reactor licensees and holders of construction permits in active or deferred status. Enclosure 2 of Reference 1 contains specific Requested Actions, Requested Information, and Required Responses associated with Near-Term Task Force (NTTF) Recommendation 2.1 for flooding hazards. Enclosure 2 of Reference 1 directed reevaluation of flooding hazards at sites and indicated that a Hazard Reevaluation Report (HRR) would be due within one to three years from the date of Reference 1 letter. On May 11, 2012, the NRC issued the Reference 2 letter that contained the NRC's prioritization plan and due dates for licensees' submittal of HRRs.
The Monticello Nuclear Generating Plant (MNGP) operated by Northern States Power Company (NSPM), a Minnesota corporation, d/b/a Xcel Energy, was identified as a Category 2 site in Reference 2 and was required to submit the HRR by March 12, 2014.
In Reference 3, the NRC provided supplemental information stating incomplete HRRs that only contain an analysis of some flooding hazard mechanisms would not be of substantive benefit for staff review and would not be acceptable. Therefore, Reference 3 recommends licensees not submit partial reports, but instead submit an extension request.
The purpose of this Enclosure is to request an extension to the March 12, 2014 due date for the submittal of the HRR for MNGP. As recommended in Reference 3, the reasons for the delay, the proposed schedule for the submittal of the complete HRR, and the basis for the acceptability of the revised schedule are described below.
2.0 Reasons for the Delay Completion of Site-Specific Analyses:
NSPM plans to follow the hierarchical hazard approach (HHA) concept to refine site specific data that is discussed in the Reference 1 letter. The HHA is a progressively refined, stepwise estimation of site-specific hazards that evaluates the safety of Systems, Structures and Components (SSCs) with the most conservative plausible assumptions consistent with available data. The HHA process starts with the most conservative simplifying assumptions that maximize the hazards from the probable maximum event for each natural flood-causing phenomenon expected to occur in the vicinity of a proposed site. If the site is not inundated by floods from any of the phenomena to an elevation critical for safe operation of the SSCs, a conclusion that the SSCs are not susceptible to flooding would be valid, and no further flood-hazard assessment would be needed. However, if the level of assessed hazards results in an adverse effect or exposure to any safety related SSC, a more site-specific hazard Page 2 of 5
En'closure NSPM Request For Extension assessment should be performed for the probable maximum event. Several iterations of the flood hazard assessment, each based on inclusion of additional site-specific data, may be needed to demonstrate that the assessed hazards from the probable maximum event are still based on conservative assumptions yet do not adversely affect the safety-related SSCs.
NSPM is working to refine the hazards assessment using more site-specific inputs and assumptions. The extended due date provides the additional time required for NSPM to perform the analytical refinements per the methodology described above.
US Army Corps of Engineers (USAGE) Dam Information:
Additional detailed technical information is needed to facilitate evaluation of the dams as part of the HHA approach. NSPM understands that the NRC is interfacing with the USAGE to obtain dam information and NSPM has submitted a request for technical assistance (Reference 4). NSPM intends to use the information from the USAGE evaluations as part of the above described analytical refinements.
3.0 Proposed Submittal Schedule NSPM will submit the required flood HRR for MNGP within 10 months of receiving the USAGE's final information. This timing supports incorporation of the USAGE's information and the site-specific analytical refinements into the HRR.
NSPM continues to validate and improve site readiness in regard to implementation of existing flood protection features and mitigating strategies. These efforts include improvement of flooding procedures, simulation of flood protection actions to validate effectiveness, and improvement of site flood response readiness through plant modifications and pre-staging of materials.
4.0 Basis for Acceptability of the Revised Schedule NSPM's proposed submittal schedule extension is acceptable based on the discussion below:
The NRC's March 12, 2012, 50.54(f) cover letter states that the current regulatory approach and the resultant plant capabilities provide confidence that an accident with consequences similar to the Fukushima accident is unlikely to occur in the United States. The NRC letter concluded that continued plant operation and the continuation of licensing activities do not pose an imminent risk to public health and safety.
Page 3 of 5
Enclosure NSPM Request For Extension The events being analyzed in the MNGP HRR are beyond the plant's design and licensing basis as noted in Reference 3. In accordance with Enclosure 2 of the March 12, 2012, 50.54(f) letter item 1.d, interim evaluations and actions will be taken or planned to address any reevaluated higher flooding hazards relative to the design basis.
These interim evaluations and actions, if any, will be included in the complete MNGP HRR as part of the required response.
NSPM's position is that, assessed qualitatively, the reevaluated flooding hazard is an unlikely event and is not likely to occur within the extension request timeframe. The table below compares the Historical Maximum Observed River Elevation, the 1000 year flood near the site, the current design bases probable maximum flood, and the flood protection elevation for the MNGP site, which demonstrates the margin between the analyzed flood and MNGP's flood protection.
Table -Flood Elevations Elevation Description Elevation Historical Maximum Peak Stage (Approximate) 1 916ft Estimated 1 000-year Flood Elevation 921 ft Plant Grade (Approximate) 930ft Design Bases Probable Maximum Flood 939.2 ft Flood Protection Elevation 941ft Note 1: Maximum flood of record occurred in 1965.
5.0 References
- 1.
NRC Letter, "Request for Information Pursuant to Title 10 of the Code of Federal Regulations 50.54(f) Regarding Recommendations 2.1, 2.3, and 9.3, of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident," dated March 12, 2012 (ADAMS Accession No. ML12053A340).
- 2.
NRC Letter, "Prioritization of Response Due Dates for Request for Information Pursuant to Title 10 of the Code of Federal Regulations 50.54(f) Regarding Flooding Hazard Reevaluations for Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident," dated May 11, 2012 (ADAMS Accession No. ML12097A509).
Page 4 of 5
Enclosure NSPM Request For Extension
- 3.
NRC Letter, "Supplemental Information Related to Request for Information Pursuant to Title 10 of the Code of Federal Regulations 50.54(f)
Regarding Flooding Hazard Reevaluations for Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident," dated March 1, 2013 (ADAMS Accession No. ML13044A561).
- 4.
NSPM Letter, "Request for NRC Assistance to Obtain Information on Dams from the U.S. Army Corps of Engineers (USAGE)," dated March 5, 2014.
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