ML14035A216

Seabrook Station, Update to Response to NRC 10 CFR 50.54(f) Request for Information Regarding Near-Term Task Force Recommendation 2.3, Flooding Review of Available Physical Margin Assessments

ML14035A216
Person / Time
Site:	Seabrook
Issue date:	01/30/2014
From:	Walsh K NextEra Energy Seabrook
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
SBK-L-14016
Download: ML14035A216 (4)

Text

NEXTera ENERGA7Y1 January 30, 2014 10 CFR 50.54(f)SBK-L-14016 Docket No. 50-443 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555 Seabrook Station Update to Response to NRC 10 CFR 50.54(f) Request for Information Regarding Near-Term Task Force Recommendation 2.3, Flooding Review of Available Physical Margin Assessments

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.(Accession No. ML12073A348)

(2) NRC Letter to Nuclear Energy Institute, Endorsement of Nuclear Energy Institute (NEI) 12-07, "Guidelines for Performing Verification Walkdowns of Plant Flood Protection Features," dated May 31, 2012. (Accession No. ML12144A142)

(3) NextEra Energy Letter, SBK-L-12243, Response to NRC 10 CFR 5054(f) Request for Information Regarding Near-Term Task Force Recommendation 2.3. Flooding, dated November 27, 2012.(4) NRC Letter, Request for Additional Information Associated with Near-Term Task Force Recommendation 2.3, Flooding Walkdowns; dated December 23, 2013. (Accession No.ML13325A891)

On March 12, 2012, the NRC staff issued Reference 1 requesting information pursuant to Title 10 of the Code of Federal Regulations

§50.54(f).

Enclosure 4 of that letter contains specific requested information associated with Near-Term Task Force Recommendation 2.3 for Flooding.Per Reference 2, the NRC endorsed Nuclear Energy Institute (NEI) 12-07, "Guidelines for Performing Verification Walkdowns of Plant Flood Protection Features," dated May 31, 2012.NextEra Energy Seabrook, LLC, P.O. Box 300, Lafayette Road, Seabrook, NH 03874

'U.S. Nuclear Regulatory Commission SBK-L-14016/Page 2 By Reference 3, NextEra Energy Seabrook, LLC (NextEra) submitted the final report in response to the request for information.

One of the requirements of NEI 12-07 is to identify the available physical margin (APM)associated with each applicable flood protection feature, determine if the margin provided is small, and evaluate any small margins that have potentially significant consequences through the corrective action process. The results of this effort were to be maintained on site for future NRC audits.Following the NRC staff's initial review of the walkdown reports, regulatory site audits were conducted at a sampling of plants. Based on the walkdown report reviews and site audits, the staff identified additional information necessary to allow them to complete its assessments.

Accordingly, by Reference 4 the NRC staff has issued a request for addition information (RAI).The RAI questions and the NextEra responses are provided below.RAI Number 1: Confirmation that the process for evaluating APM was reviewed Response:

NextEra has completed a review of the process used at Seabrook Station to evaluate APMs.RAI Number 2: Confirmation that the APM process is now or was always consistent with the guidance in NEI 12-07 and discussed in this RAI.Response:

The original walkdown effort at Seabrook Station followed the guidance provided in NEI 12-07, including a definition for a small margin. Additional actions have been taken to make the process consistent with the information provided in this RAI.RAI Number 3. If changes are necessary, a general description of any process changes to establish this consistency.

Response:

As stated above, the original walkdown effort followed the guidance provided in NEI 12-07, including a definition for a small margin. However, a specific APM had not been assigned to the seals associated with flood protection features.

These items have now been addressed in accordance with the guidance provided in this RAI and entered into the NextEra corrective action process, as appropriate, for further evaluation.

RAI Number 4: As a result of the audits and subsequent interactions with industry during public meetings, NRC staff recognized that evaluation ofAPMfor seals (e.g., flood doors, penetrations, floodgates, etc.) was challenging for some licensees.

Generally, licensees were expected to use either Approach A or Approach B (described below) to determine the APMfor seals: a) If seal pressure ratings were known, the seal ratings were used to determine APM (similar to example 2 in Section 3.13 ofNEI 12-07). A numerical value for APM was documented.

No further action was performed if the APM value was greater than the pre-established small-margin threshold value. If the APM value was

• U.S. Nuclear Regulatory Commission SBK-L-14016/Page 3 small, an assessment of "significant consequences" was performed and the guidance in NEI 12-07 Section 5.8 was followed.b) If the seal pressure rating was not known, the APM for seals in a flood barrier is assumed to be greater than the pre-established small-margin threshold value if the following conditions were met: (1) the APMfor the barrier in which the seal is located is greater than the small-margin threshold value and there is evidence that the seals were designed/procured, installed, and controlled as flooding seals in accordance with the flooding licensing basis. Note that in order to determine that the seal has been controlled as aflooding seal, it was only necessary to determine that the seal configuration has been governed by the plant's design control process since installation.

In this case, the APMfor the seal could have been documented as "not small".As part of the RAI response, state if either Approach A or Approach B was used as part of the initial walkdowns or as part of actions taken in response to this RAI. No additional actions are necessary if either Approach A or B was used If neither Approach A or B was used to determine the APM values for seals (either as part of the walkdowns or as part of actions taken in response to this RAI), then perform the following two actions: " Enter the condition into the CAP (note. it is acceptable to utilize a single CAP entry to capture this issue for multiple seals). CAP disposition of "undetermined" APM values for seals should consider the guidance provided in NEI 12-07, Section 5.8. The CAP disposition should confirm all seals can perform their intended safety function against floods up to the current licensing basis flood height. Disposition may occur as part of the Integrated Assessment.

If an Integrated Assessment is not petformed, determine whether there are significant consequences associated with exceeding the capacity of the seals and take interim action (s), if necessary, via the CAP processes.

These actions do not need to be complete prior to the RAI response." Report the APM as "undetermined" andprovide the CAP reference in the RAI response.Response:

Neither Approach A or B, as described above, were used to determine the APM values for seals and below grade walls/floors.

As part of the actions taken to address this RAI, the seals and below grade walls/floors have been assigned an APM value of "undetermined" and have been entered into the CAP process through Action Request 1934467 for further evaluation of their available physical margin. Implementation of interim actions will be pursued, if necessary.

This letter contains no new Regulatory Commitments and no revision to existing Regulatory Commitments.

U.S. Nuclear Regulatory Commission SBK-L-14016/Page 4 Should you have any questions regarding this submittal, please contact Mr. Michael Ossing, Licensing Manager at 603-773-7512.

I declare under penalty of perjury that the foregoing is true and correct.Executed on January _ 2014.Sincerely, Kevin Walsh Site Vice President NextEra Energy Seabrook, LLC cc: NRC Region I Administrator J. G. Lamb, NRC Project Manager NRC Senior Resident Inspector