ML14035A220

Cooper, Response to Nuclear Regulatory Commission'S Request for Information Associated with Near-Term Task Force Recommendation 2.3, Flooding Walkdowns

ML14035A220
Person / Time
Site:	Cooper
Issue date:	01/31/2014
From:	Higginbotham K Nebraska Public Power District (NPPD)
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
NLS2014011
Download: ML14035A220 (5)

Text

NNebraska Public Power DistrictNLS2014011 Always there when you need usJanuary 31, 2014U.S. Nuclear Regulatory Commission ATTN: Document Control Desk11555 Rockville PikeRockville, MD 20852

Subject:

Nebraska Public Power District's Response to Nuclear Regulatory Commission's Request for Information Associated with Near-Term Task Force Recommendation 2.3, Flooding Walkdowns Cooper Nuclear Station, Docket No. 50-298, DPR-46

References:

1. Nuclear Regulatory Commission Letter, Request for Information Pursuant toTitle 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 ofInsights from the Fukushima Dai-Ichi

Accident, dated March 12, 2012(Accession No. ML12053A340)

2. Nuclear Regulatory Commission Letter to Nuclear Energy Institute, Endorsement of Nuclear Energy Institute (NE1) 12-07, "Guidelines forPerforming Verification Walkdowns of Plant Flood Protection Features,"

dated May 31, 2012 (Accession No. ML12144A142)

3. Nebraska Public Power District Letter to Nuclear Regulatory Commission, Flooding Walkdown Report -Nebraska Public Power District's Response toNuclear Regulatory Commission Request for Information Pursuant to 10 CFR50.540l Regarding the Flooding Aspects of Recommendation 2.3 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi

Accident, dated November 27, 2012 (NLS2012124)

4. Nuclear Regulatory Commission Letter, Request for Additional Information Associated with Near-Term Task Force Recommendation 2.3, FloodingWalkdowns, dated December 23, 2013 (Accession No. ML13325A891)

Dear Sir or Madam:

On March 12, 2012, the Nuclear Regulatory Commission (NRC) issued Reference 1 requesting information pursuant to Title 10 of the Code of Federal Regulations 50.54(f).

Enclosure 4 ofReference 1 contains specific Requested Information associated with Near-Term Task ForceRecommendation 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. By Reference 3, Nebraska Public Power District (NPPD)submitted the final report in response to the request for information.

COOPER NUCLEAR STATION /d bP.O. Box 98 / Brownville, NE 68321-0098 Telephone:

(402) 825-3811

/ Fax: (402) 825-5211www.nppd.com NLS2014011 Page 2 of 2One of the requirements of NEI 12-07 is to identify the available physical margin associated witheach applicable flood protection

feature, determine if the margin provided is small, and evaluateany small margins that have potentially significant consequences through the corrective actionprocess.

The results of this effort were to be maintained on site for future NRC audits.Following the NRC's initial review of the walkdown

reports, regulatory site audits wereconducted at a sampling of plants. Based on the walkdown report reviews and site audits, theNRC identified additional information necessary to allow the staff to complete its assessments.

Accordingly, by Reference 4, the NRC has issued a request for additional information (RAI). TheRAI questions and NPPD's responses are provided in the Attachment.

This letter contains no new regulatory commitments and no revision to existing regulatory commitments.

Should you have any questions regarding this submittal, please contact DavidVan Der Kamp, Licensing

Manager, at (402) 825-2904.

I declare under penalty of perjury that the foregoing is true and correct.Executed on: i/ Z///!Sincerely, Kenneth Higginboth General Manager of lant Operations

/bk

Attachment:

Response to Request for Additional Information Associated with Near-Term TaskForce Recommendation 2.3, Flooding Walkdowns cc: Regional Administrator, w/attachment USNRC -Region IVDirector, w/attachment USNRC -Office of Nuclear Reactor Regulation Cooper Project Manager, w/attachment USNRC -NRR Project Directorate IV-ISenior Resident Inspector, w/attachment USNRC -CNSNPG Distribution, w/attachment CNS Records, w/attachment NLS201401 1Attachment Page 1 of3Attachment Response to Request for Additional Information Associated withNear-Term Task Force Recommendation 2.3, Flooding Walkdowns Cooper Nuclear Station, Docket No. 50-298, DPR-46On March 12, 2012, the Nuclear Regulatory Commission (NRC) issued a letter requesting information per 10 CFR 50.54(f).

The request for information letter contained specific requested

actions, requested information and required responses associated with Recommendation 2.3 forflooding walkdowns.

By letter on May 31, 2012, the NRC endorsed Nuclear Energy Institute (NEI) 12-07 as providing acceptable guidelines for performing walkdowns of plant floodprotection features.

Nebraska Public Power District (NPPD) submitted a final walkdown reportfor Cooper Nuclear Station (CNS) in response to the request for information on November 27,2012.Following the NRC's initial review of the walkdown

reports, regulatory site audits wereconducted at a sampling of plants. Based on the walkdown report reviews and site audits, theNRC identified additional information necessary to allow the staff to complete its assessments.

The NRC observed that several licensees did not always determine and document available physical margin (APM) in a consistent manner that met the expected interpretation of NEI 12-07.On December 23, 2013, the NRC transmitted a request for additional information (RAI)regarding the determination and documentation of APM. Below are the NRC's RAI questions and NPPD's responses.

NRC Request:Please provide the following:

1. Confirmation that the process for evaluating APM was reviewed; NPPD Response:

NPPD confirms that it has completed a review of the process used at CNS toevaluate APM.2. Confirmation that the APM process is now or was always consistent with the guidance in NEI12-07 and discussed in this RAI;NPPD Response:

NPPD confirms the original walkdown effort was consistent with theguidance provided in NEI 12-07. A numerical value for a small APM was not initially established.

NLS2014011 Attachment Page 2 of 33. If changes are necessary, a general description of any process changes to establish thisconsistency; NPPD Response:

No changes were necessary as the original walkdown effort followed theguidance provided in NEI 12-07. While a numerical value for small APM was not established, judgment was used to determine if a feature had to be entered into CNS' Corrective ActionProgram (CAP). In response to this RAI, an engineering report, ER-14-001, was developed todetermine a numerical value for small APM. This report concluded that features with one footor more APM were determined to be not small. Features with less than one foot APM wereentered into the CAP. In the case of building walls, the walkdown team judged that excessmargin was available.

As such, walls were not entered into the CAP, although the walkdownsheets state that the APM is zero.4. As a result of the audits and subsequent interactions with industry during public meetings, NRC staff recognized that evaluation of APM for seals (e.g., flood doors, penetrations, floodgates, etc.) was challenging for some licensees.

Generally, licensees were expected to useeither Approach A or Approach B (described below) to determine the APM for seals:a) If seal pressure ratings were known, the seal ratings were used to determine APM(similar to example 2 in Section 3.13 of NEI 12-07). A numerical value for APM wasdocumented.

No further action was performed if the APM value was greater than the pre-established small-margin threshold value. If the APM value was small, an assessment of"significant consequences" was performed and the guidance in NEI 12-07 Section 5.8was followed.

b) If the seal pressure rating was not known, the APM for seals in a flood barrier isassumed to be greater than the pre-established small-margin threshold value if thefollowing conditions were met: (1) the APMfor the barrier in which the seal is located isgreater than the small-margin threshold value and there is evidence that the seals weredesigned/procured, installed, and controlled as flooding seals in accordance with theflooding licensing basis. Note that in order to determine that the seal has been controlled as a flooding seal, it was only necessary to determine that the seal configuration has beengoverned 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 ifeither Approach A or Approach B was used as part of theinitial walkdowns or as part of actions taken in response to this RAI. No additional actionsare 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 ofthe 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 entryto capture this issue for multiple seals). CAP disposition of "undetermined" APMvalues for seals should consider the guidance provided in NEI 12-0 7, Section 5.8. The NLS2014011 Attachment Page 3 of 3CAP disposition should confirm all seals can perform their intended safety functionagainst floods up to the current licensing basis flood height. Disposition may occuras part of the Integrated Assessment.

If an Integrated Assessment is not performed, determine whether there are significant consequences associated with exceeding thecapacity 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" and provide the CAP reference in the RAIresponse.

NPPD Response:

Approach "A" was used to determine APM for seals as part of the originalwalkdowns.

As such, no additional actions are necessary.