PNP 2014-008, 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

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

ML14034A168
Person / Time
Site:	Palisades
Issue date:	01/30/2014
From:	Vitale A Entergy Nuclear Operations
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
PNP 2014-008
Download: ML14034A168 (4)

Text

a Entergy Entergy Nuclear Operations, Inc.

Palisades Nuclear Plant 27780 Blue Star Memorial Highway Covert, MI 49043-9530 Tel 269 764 2000 Anthony J. Vitale Site Vice President PNP 2014-008 January 30, 2014 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk 11555 Rockville Pike Rockville, MD 20852

SUBJECT:

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 Palisades Nuclear Plant Docket 50-255 License No. DPR-20

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-lchi Accident,"

dated March 12, 2012 (ADAMS Accession Number ML12056A046).

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 (ADAMS Accession Number ML12144A142).

3. Entergy Nuclear Operations, Inc. letter to NRC, PNP 2012-101, "Flooding Walkdown Report - Response to NRC Request for Information Pursuant to 10 CFR 50.54(f) 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 (ADAMS Accession Number ML12332A377).

4. NRC letter, "Request for Additional Information Associated with Near-Term Task Force Recommendation 2.3, Flooding Walkdowns," dated December 23, 2013 (ADAMS Accession Number ML13325A891) /p t Pfi

PNP 2014-008 Page 2

Dear Sir or Madam:

On March 12, 2012, the NRC staff issued Reference 1, which requested 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." In Reference 3, Entergy Nuclear Operations, Inc.

(ENO) 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 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 additional information (RAI). The RAI questions and the ENO responses for the Palisades Nuclear Plant (PNP) are provided below.

RAI Number 1: Confirmation that the process for evaluating APM was reviewed.

ENO Response: ENO has completed a review of the process used at PNP to evaluate available 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.

ENO Response: The original walkdown effort followed the guidance provided in NEI 12-07, including the 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 generaldescription of any process changes to establish this consistency.

ENO 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.

PNP 2014-008 Page 3 These items have now been addressed in accordance with the guidance provided in this RAI.

RAI Number 4: As a result of the audits and subsequent interactionswith industry during public meetings, NRC staff recognized that evaluation of APM for seals (e.g.,

flood doors, penetrations,flood gates, etc.) was challengingfor some licensees.

Generally, licensees were expected to use either 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 determineAPM (similarto example 2 in Section 3.13 of NEI 12-07). A numericalvalue for APM was documented. No furtheraction was performed if the APM value was greaterthan the pre-establishedsmall-margin threshold value. If the APM value was small, an assessment of "significantconsequences"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 barrieris assumed to be greaterthan the pre-establishedsmall-margin threshold value if the following conditions were met: (1) the APM for the barrierin which the seal is located is greaterthan the small-margin threshold value and there is evidence that the seals were designed/procured,installed, and controlledas flooding seals in accordancewith the flooding licensing basis. Note that in order to determine that the seal has been controlledas a flooding seal, it was only necessary to determine that the seal configurationhas been governed by the plant's design controlprocess since installation. In this case, the APM for the seal could have been documented as "notsmall".

As part of the RAI response, state if eitherApproach A or Approach B was used as part of the initial walkdowns or as part of actions taken in response to this RAI. No additionalactions are necessary if eitherApproach A or B was used.

If neither Approach A or B was used to determine the APM values for seals (eitheras part of the walkdowns or as partof 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 dispositionshould confirm all seals can perform their intended safety function againstfloods up to the currentlicensing basis flood height. Disposition may occuras part of the IntegratedAssessment. If an IntegratedAssessment is not performed, determine whether there are significant consequences associatedwith exceeding the capacity of the seals and take

PNP 2014-008 Page 4 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 RAI response.

ENO Response: Approach B, described above, was used to determine the APM values for seals. When the seal pressure rating was not known, the APM for these seals is assumed to be greater than the pre-established small-margin threshold value.

The conditions described above were met, as the APM for 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 PNP flooding licensing basis. All of the seals were inspected as part of the original walkdowns for signs of degradation, and corrective actions were taken, when required.

This letter contains no new or revised commitments.

I declare under penalty of perjury that the foregoing is true and correct. Executed on January 30, 2014.

Sincerely,

/

ajv/jse cc: Administrator, Region III, USNRC Project Manager, Palisades, USNRC Resident Inspector, Palisades, USNRC