ML090550981

Lr Hearing - Draft RAIs for 5 Open Items

ML090550981
Person / Time
Site:	Indian Point
Issue date:	02/24/2009
From:	Office of Nuclear Reactor Regulation
To:	Division of License Renewal
References
Download: ML090550981 (5)

Text

1 IPRenewal NPEmails From:

Kimberly Green Sent:

Tuesday, February 24, 2009 5:07 PM To:

STROUD, MICHAEL D; Tyner, Donna Cc:

George Thomas; Bryce Lehman; Hansraj Ashar; Rajender Auluck; IPRenewal NPEmails; David Wrona; Sherwin Turk

Subject:

Draft RAIs for 5 Open Items Attachments:

Followup DRAIs Structures 2-24-08.doc Mike and Donna, Attached are draft RAIs for 5 of the open items identified in SER. Please review and let me know if Entergy would like to have a telephone call. The purpose of the call would be to obtain clarification on the staff's draft RAIs.

KimberlyGreen SafetyPM (301)4151627 kimberly.green@nrc.gov

Hearing Identifier:

IndianPointUnits2and3NonPublic_EX Email Number:

1152 Mail Envelope Properties (83F82891AF9D774FBBB39974B6CB134F7EC0FB4EBD)

Subject:

Draft RAIs for 5 Open Items Sent Date:

2/24/2009 5:07:23 PM Received Date:

2/24/2009 5:07:25 PM From:

Kimberly Green Created By:

Kimberly.Green@nrc.gov Recipients:

"George Thomas" <George.Thomas2@nrc.gov>

Tracking Status: None "Bryce Lehman" <Bryce.Lehman@nrc.gov>

Tracking Status: None "Hansraj Ashar" <Hansraj.Ashar@nrc.gov>

Tracking Status: None "Rajender Auluck" <Rajender.Auluck@nrc.gov>

Tracking Status: None "IPRenewal NPEmails" <IPRenewal.NPEmails@nrc.gov>

Tracking Status: None "David Wrona" <David.Wrona@nrc.gov>

Tracking Status: None "Sherwin Turk" <Sherwin.Turk@nrc.gov>

Tracking Status: None "STROUD, MICHAEL D" <MSTROUD@entergy.com>

Tracking Status: None "Tyner, Donna" <dtyner@entergy.com>

Tracking Status: None Post Office:

HQCLSTR01.nrc.gov Files Size Date & Time MESSAGE 380 2/24/2009 5:07:25 PM Followup DRAIs Structures 2-24-08.doc 54778 Options Priority:

Standard Return Notification:

No Reply Requested:

No Sensitivity:

Normal Expiration Date:

Recipients Received:

INDIAN POINT NUCLEAR GENERATING UNIT NOS. 2 AND 3 LICENSE RENEWAL APPLICATION DRAFT REQUEST FOR ADDITIONAL INFORMATION (D-RAI)

Follow-up D-RAI 1: Question 359 - Open Item 3.0.3.2.15-1 In Entergy Letter NL-08-169, dated November 6, 2008, Additional Information Regarding License Renewal Application-Operating Experience Clarification, the applicant submitted a supplemental clarification, describing its plan for implementing a permanent remediation of the Indian Point Nuclear Generating Unit No. 2 (IP2) refueling cavity leakage over the next three scheduled IP2 re-fueling outages (2010, 2012, 2014).

The transmittal letter NL-08-169, dated November 6, 2008, states: There are no new commitments identified in this submittal. The applicant has previously taken a bore sample in the region of the leak, and has committed to take another sample prior to entering the period of extended operation. In absence of a formal commitment to remedy the source of leakage, the applicants AMP should include a method to monitor for a degrading condition in the refueling cavity, and other structures affected by the leakage, during the period of extended operation, or the applicant should explain how the Structural Monitoring Program will adequately manage potential aging of this region during the period of extended operation.

Follow-up D-RAI 2: Question 360 - Open Item 3.0.3.2.15-2 In Entergy Letter NL-08-169, dated November 6, 2008, the applicant submitted a supplemental clarification for the IP2 spent fuel pool pit walls, which provides a detailed description of (1) the design margins for the spent fuel pool concrete walls; and (2) the results of prior concrete core sample testing and rebar corrosion testing.

a.

In Commitment 25, the applicant commits to sample for tritium in groundwater wells in close proximity to the IP2 spent fuel pool at least every three months to assess for potential indications of spent fuel pool leakage. This commitment does not describe what actions will be taken if leakage continues. If sampling indicates continued leakage, the applicants AMP should include a method to determine if a degraded condition exists during the period of extended operation, or the applicant should explain how the Structural Monitoring Program will adequately manage potential aging of the inaccessible concrete of the IP2 spent fuel pool due to borated water leakage during the period of extended operation.

b.

The second paragraph on page 2 of Attachment 1 of the clarification letter dated November 6, 2008, states in part: [l]ittle or no corrosion was observed in the rebar except at a location in the wall where spalling had occurred exposing rebar to the elements. Analysis of the rust particles showed high chloride content and low boron concentration indicating that rainwater was the primary cause of the observed corrosion. The staff requests the applicant to identify any Unit 2 and Unit 3 operating experience related to rebar corrosion, in light of the chloride content in rainwater, and identify the likely source for the high chloride content in the rainwater. Further the applicant is requested to explain whether and how the AMP is adequate to address this environment and the related potential aging effects to ensure there is no loss of intended function during the period of extended operation.

Follow-up D-RAI 3: Question 361 - Open Item 3.0.3.3.2-1 In Entergy Letter NL-08-169, dated November 6, 2008, the applicant submitted a supplemental clarification for IP containment spalling, describing the design margins for the Indian Point (IP) containment structures at the locations of existing concrete degradation on the vertical wall.

Based on its review of the information, the staff identified areas that need further clarification and/or additional information to complete its review as described below:

a.

The clarification for the IP containment spalling states: As the surface concrete is not credited for tensile strength of the structure, the spalling has no impact on the available margins. The strength margins identified appear to be based on the nominal rebar dimensions, without any consideration for rebar degradation due to exposure and potential loss of bond between the concrete and the rebar. Explain whether, and if so how, the existing degradation and design margin will be considered in performing periodic inspections to monitor degradation, to ensure there is no loss of containment intended function during the period of extended operation.

b.

In the spent fuel pool discussion, in the letter dated November 6, 2008, the applicant stated: Little or no corrosion was observed in the rebar except at a location in the wall where spalling had occurred exposing rebar to the elements. Analysis of the rust particles showed high chloride content and low boron concentration indicating that rainwater was the primary cause of the observed corrosion. The applicant is requested to explain the adequacy of the 5-year IWL frequency of inspection of the degraded areas of the IP containments during the period of extended operation, considering the possibility of an increased site-specific corrosion rate of the exposed rebar on the containments.

Follow-up D-RAI 4: Open Item 3.5-1 In Entergy Letter NL-08-169, dated November 6, 2008, the applicant submitted a supplemental clarification to LRA Section 3.5.2.2 related to the concrete mix design method and the durability of concrete used at IP. In the LRA the applicant claimed that concrete meets the specifications of ACI 318-63 and the intent of ACI 201.2R-77, Guide to Durable Concrete. As a result the applicant claimed that several aging effects were not applicable to inaccessible concrete. Based on its review of the information, the staff identified areas that need further clarification and/or additional information to determine that the applicant meets the cited ACI specifications such that further evaluation is not necessary as recommended by the GALL Report.

a.

In the clarification to LRA Section 3.5.2.2 (Part 1) on page 6 of Attachment 1 to letter NL-08-169, the applicant stated that it used Method 2 of Section 502 of ACI 318-63 by testing trial mixes to determine the water-cement ratios for the concrete mix design of the IP containments and other structures. In order for the staff to evaluate the quality of concrete in IP structures that may be subject to degradation during the period of extended operation, the staff requests the applicant to define the water-cement ratio that was specified at the time of construction. The applicant is requested to provide this information for the IP containments and other safety-related IP Unit 2 and 3 concrete structures, including the refueling cavities and the spent fuel pools.

b.

In order for the staff to understand the parameters related to concrete strength and durability during the period of extended operation, the applicant is requested to describe

the methodology used to establish the required concrete compressive strength of 3000 psi for the containment and other safety-related concrete structures, in accordance with ACI 318-63, Method 2. The applicant is requested to provide a summary of the results of statistical analyses performed, if any, of the original concrete strength tests, including number of samples, raw strength values from the test, the mean, the standard deviation, and the original criterion (e.g., mean minus 1 standard deviation, coefficient of variation) used to confirm that the required compressive strength was achieved, and can be relied upon during the period of extended operation such that further evaluation is not necessary as recommended by the GALL Report.

c.

If the applicant is unable to provide the information requested in parts (a) and (b) above, the applicant is requested to explain how the aging effects on concrete will be adequately managed during the period of extended operation.

Follow-up D-RAI 5: Open Item 3.5-2 In Entergy Letter NL-08-169, dated November 6, 2008, Additional Information Regarding License Renewal Application-Operating Experience Clarification, the applicant submitted a supplemental clarification to LRA Section 3.5.2.2 (Part 3) for IP2 containment concrete and its ability to withstand local area temperatures up to 250ºF. The staff has identified areas that need further clarification and/or additional information as discussed below:

a.

In the clarification to LRA Section 3.5.2.2 (Part 3) on page 7 of Attachment 1 to letter NL-08-169, the applicant stated that a 15% reduction of concrete strength could be expected when reaching temperatures of 250ºF and that concrete compressive strength tests showed an actual strength more than 15% higher than design strength. Please provide the methodology used to arrive at the conclusion that the actual concrete strength is more than 15% greater than 3000 psi, (i.e., greater than 3450 psi). Provide a summary of the results, including number of samples, raw strength values from the test, the mean, the standard deviation, and the original criterion (e.g., mean minus 1 standard deviation) used to confirm that the claimed strength was achieved.

b.

Please explain how consideration was given to the reduction in modulus of elasticity in the high temperature concrete evaluation.

c.

If the applicant is unable to provide the information requested in parts (a) and (b) above, the applicant is requested to explain how the aging effects on concrete, due to high temperatures, will be adequately managed during the period of extended operation.