ML081830665
| ML081830665 | |
| Person / Time | |
|---|---|
| Site: | Indian Point  |
| Issue date: | 06/20/2008 |
| From: | Office of Nuclear Reactor Regulation |
| To: | Division of License Renewal |
| References | |
| Download: ML081830665 (6) | |
Text
IPRenewal NPEmails From: Kimberly Green Sent: Friday, June 20, 2008 11:52 AM To: STROUD, MICHAEL D; Tyner, Donna Cc: Andrew Stuyvenberg
Subject:
Draft RAI on structures OE Attachments: Draft RAIs Structures OE 06-20-08.doc Mike and Donna, Attached is the draft RAI on structures OE. Please look over and let me know if you require a telephone conference. The purpose of the telephone conference will be to obtain clarification on the staff's request.
Please note that I will be in training June 25 - 27. If a telecon is needed during that time, please contact Drew Stuyvenberg at 301-415-4006.
- Thanks, Kimberly Green Safety PM (301) 4151627 kimberly.green@nrc.gov 1
Hearing Identifier: IndianPointUnits2and3NonPublic_EX Email Number: 133 Mail Envelope Properties (Kimberly.Green@nrc.gov20080620115100)
Subject:
Draft RAI on structures OE Sent Date: 6/20/2008 11:51:35 AM Received Date: 6/20/2008 11:51:00 AM From: Kimberly Green Created By: Kimberly.Green@nrc.gov Recipients:
"Andrew Stuyvenberg" <Andrew.Stuyvenberg@nrc.gov>
Tracking Status: None "STROUD, MICHAEL D" <MSTROUD@entergy.com>
Tracking Status: None "Tyner, Donna" <dtyner@entergy.com>
Tracking Status: None Post Office:
Files Size Date & Time MESSAGE 530 6/20/2008 11:51:00 AM Draft RAIs Structures OE 06-20-08.doc 48634 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)
OPERATING EXPERIENCE -- STRUCTURES D-RAI 3.5-1 Containment Steel Liner Behind Insulation The staff initially raised the issue of Inspection of the Containment Steel Liner Behind Insulation in Audit Question 27. In its response, Entergy indicated that it does not remove insulation to inspect the steel liner, on the basis that the liner behind the insulation is considered inaccessible, and constitutes less than 20% of the total liner surface area.
The staff subsequently determined that insulation had been placed over the damaged liner area in IP2, shortly after the 1973 feedwater line break accident. The extent of the damage was a strip approximately 5 high and 50 around the circumference.
In addition, Entergy has reported some minor corrosion of the IP2 liner behind the insulation, at the juncture with the concrete floor slab.
The staff requests that Entergy commit to a one-time inspection of the containment steel liner behind the insulation for (1) the damaged area of the IP2 steel liner; and (2) the IP3 steel liner at the juncture with the concrete floor slab, prior to entering the extended period of operation, in order to confirm that no liner degradation has occurred in these areas.
D-RAI 3.5-2 Water Control Structures Degradation:
Entergy addressed plant-specific degradation of water control structures in response to Audit Question 358. The applicant provided responses to the staffs request for the following information:
(a) history of the degradation; (b) evaluation of the extent of degradation; (c) operability assessments performed; (d) corrective actions taken; (e) the current status of the degraded condition; (f) corrective actions planned prior to the LR period; (g) special or augmented aging management requirements during the period of extended operation; (h) license renewal commitments.
The information provided for items (a) through (f) is generally sufficient for the staff to gain an understanding of the details of the degradation that has been experienced. However, the responses to items (g) and (h) need additional clarification.
Entergy has identified conditions of degradation in certain known safety-significant areas that have not been repaired or corrected. However, in its response, Entergy makes no commitment to enhance the inspection of these areas during the extended period of 1
operation, if the degraded conditions are not repaired or corrected prior to the extended period of operation. Therefore, the staff requests that Entergy provide the technical basis for concluding that enhanced inspection is not necessary for these areas during the extended period of operation.
D-RAI 3.5-3 IP2 Reactor Cavity Leakage:
Entergy addressed plant-specific degradation of the IP2 reactor refueling cavity in response to Audit Question 359. The applicant provided responses to the staffs request for the following information:
(a) history of the degradation; (b) evaluation of the extent of degradation; (c) operability assessments performed; (d) corrective actions taken; (e) the current status of the degraded condition; (f) corrective actions planned prior to the LR period; (g) special or augmented aging management requirements during the period of extended operation; (h) license renewal commitments.
The information provided for items (a) through (f) is generally sufficient for the staff to gain an understanding of the details of the degradation that has been experienced. However, the responses to items (g) and (h) need additional clarification. Entergy has identified that an effort is in progress to determine the best approach to address and correct recurring leakage from the reactor cavity liner, and also to ensure that the underlying concrete has not degraded. However, there is no schedule presented, and there appears to be some uncertainty about the outcome of future actions to correct this condition. Therefore, the staff requests that Entergy describe the aging management program that will be implemented during the extended period of operation, if this condition is not corrected prior to entering the extended period of operation.
D-RAI 3.5-4 IP2 Spent Fuel Pool Crack/Leak Paths:
Entergy addressed plant-specific degradation of the IP2 spent fuel pool in response to Audit Question 360. The applicant provided responses to the staffs request for the following information:
(a) history of the degradation; (b) evaluation of the extent of degradation; (c) operability assessments performed; (d) corrective actions taken; (e) the current status of the degraded condition; (f) corrective actions planned prior to the LR period; (g) special or augmented aging management requirements during the period of extended operation; (h) license renewal commitments.
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The information provided for items (a) through (f) is generally sufficient for the staff to gain an understanding of the details of the degradation that has been experienced. However, the responses to items (g) and (h) are not considered acceptable.
The staff is not convinced that Entergy has completely addressed and corrected the leakage from the spent fuel pool. Further, due to the lack of a leak-chase channel and collection system at IP2 to monitor, detect and quantify potential leakage through the SFP liner, the effectiveness of the Water Chemistry AMP in controlling liner degradation is more difficult to confirm.
Therefore, the staff requests that Entergy (1) commit to a one-time inspection of the spent fuel pool liner prior to entering the extended period of operation, or provide the technical basis for concluding that such an inspection is not necessary; (2) explicitly include the Spent Fuel Pool (SFP) concrete structure as an enhancement to the Scope of Program attribute of the Structures Monitoring Program (see LRA pages B-121 through B-124) or provide the technical basis for concluding that such an enhancement is not necessary; and (3) supplement the current enhancement to the Detection of Aging Effects attribute of the Structures Monitoring Program (see LRA pages B-121 through B-124) to explicitly identify that ground water samples will be taken near the SFP and will be monitored for the presence of boric acid and radioactive isotopes, in addition to sulfates, pH and chlorides, or provide the technical basis for concluding that such an enhancement is not necessary.
RAI 3.5-5 IP2 Containment Dome Concrete Spalling:
Entergy addressed plant-specific degradation of the IP2 containment structure in response to Audit Question 361. The applicant provided responses to the staffs request for the following information:
(a) history of the degradation; (b) evaluation of the extent of degradation; (c) operability assessments performed; (d) corrective actions taken; (e) the current status of the degraded condition; (f) corrective actions planned prior to the LR period; (g) special or augmented aging management requirements during the period of extended operation; (h) license renewal commitments.
The information provided for items (a) through (f) is generally sufficient for the staff to gain an understanding of the details of the degradation that has been experienced. However, the responses to items (g) and (h) need additional clarification.
Entergy is currently using enhanced visual inspection techniques (beyond VT-3 general visual examination required by IWL) to monitor and trend the further progression of spalling and rebar corrosion at the exposed cadweld splices.
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Entergy has indicated in its response that remedial actions will be taken if the spalled areas degrade further and are found to affect structural integrity. The staff notes that the concrete spalls and exposed rusted rebar at many locations (7 indications on the dome per CR-IP2-2004-01347; 32 total indications on the containment structure per Attachment 3 to letter NL-01-038 dated April 2, 2001, with regard to the 2000 Refueling Outage ISI Program Summary Report) constitutes a pathway for water from rain or snow to potentially percolate through the concrete and find its way to the liner. This could potentially result in degradation of rebar and the containment liner even in areas away from the current spalls over the period of extended operation.
However, in its response, Entergy makes no commitment to perform enhanced inspection of these areas during the extended period of operation, even though enhanced inspection techniques are currently being implemented. Therefore, the staff requests that Entergy provide the technical basis for concluding that enhanced inspection is not necessary during the extended period of operation.
Further, Entergy is requested to provide its rationale for not proactively precluding the progression of the numerous concrete spall and rebar rust/corrosion conditions on the containment structure during the period of extended operation, by taking reasonable action to remedy this condition.
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