ML11294A346
| ML11294A346 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 10/12/2011 |
| From: | Office of Nuclear Reactor Regulation |
| To: | Division of License Renewal |
| References | |
| Download: ML11294A346 (7) | |
Text
Davis-BesseNPEm Resource From: CuadradoDeJesus, Samuel Sent: Wednesday, October 12, 2011 8:48 AM To: dorts@firstenergycorp.com Cc: Davis-BesseHearingFile Resource
Subject:
FW: FENOC Telecon Notes from October 5, 2011 Attachments: NRC telecon 100511.pdf Thanks From: dorts@firstenergycorp.com [1]
Sent: Tuesday, October 11, 2011 12:04 PM To: CuadradoDeJesus, Samuel Cc: custerc@firstenergycorp.com
Subject:
FENOC Telecon Notes from October 5, 2011 Sam..... attached are the FENOC telephone conference call notes from October 5, 2011.
Please let me know if you have questions or comments regarding the attached notes.
Thank you,
_____
Steve Dort DBNPS License Renewal 419.321.7662 work 412.974.3369 cell
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1
Hearing Identifier: Davis_BesseLicenseRenewal_Saf_NonPublic Email Number: 1842 Mail Envelope Properties (377CB97DD54F0F4FAAC7E9FD88BCA6D0806D3ECF5C)
Subject:
FW: FENOC Telecon Notes from October 5, 2011 Sent Date: 10/12/2011 8:47:32 AM Received Date: 10/12/2011 8:47:33 AM From: CuadradoDeJesus, Samuel Created By: Samuel.CuadradoDeJesus@nrc.gov Recipients:
"Davis-BesseHearingFile Resource" <Davis-BesseHearingFile.Resource@nrc.gov>
Tracking Status: None "dorts@firstenergycorp.com" <dorts@firstenergycorp.com>
Tracking Status: None Post Office: HQCLSTR01.nrc.gov Files Size Date & Time MESSAGE 1105 10/12/2011 8:47:33 AM NRC telecon 100511.pdf 32323 Options Priority: Standard Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date:
Recipients Received:
Doc No. 100511 TO: File DATE: October 5, 2011 FROM: Don Kosloff
SUBJECT:
NRC Telecon Regarding Davis-Besse License Renewal Letdown Cooler Aging Management and Structural RAI Responses NRC Attendees: Sam Cuadrado de Jesus, Jim Gavula, Abdul Sheikh, Bryce Lehman, Alice Erickson FENOC Attendees: Cliff Custer, Jon Hook, Trent Henline, Brian Kremer, Jake Hofelich, Dick Bair, James Marley, Brad Taylor, Steven Dort, Larry Hinkle, Don Kosloff This telephone conference call was initiated by Sam Cuadrado de Jesus, NRC Project Manager for Davis-Besse License Renewal. The telecon took place at 1:00 PM on October 5, 2011. The purpose of the call was to discuss Davis-Besse License Renewal Application (LRA) topics related to previous responses to NRC requests for additional information (RAIs), including RAI 2.3.3.18-4 regarding the letdown cooler replacement frequency, draft RAI B.2.40-3 related to the Intake Canal, and the FENOC responses to structural RAIs B.2.25-5 and B.2.39-9. The topics, discussion summary and action items are as follows:
Draft RAI 2.3.3.18-4
Background:
In its response to RAI 2.3.3.18-3 dated August 17, 2011, the applicant provided the following information:
- 1) The letdown coolers performed acceptably from initial startup in 1978 until 1991, when plant personnel detected contamination in the component cooling water (CCW) system, and replaced both letdown coolers in 1993. Then, in 2009, plant personnel identified a small, active reactor coolant leak, and again replaced both letdown coolers in 2010.
- 2) A failure analysis had not been performed on the leaking letdown coolers to determine the specific leak location or to verify the failure mechanism because of high radiation dose rates associated with that effort.
SRP-LR Section A.1.2.3.4, "Detection of Aging Effects," states that nuclear power plants are licensed using the principles of redundancy, and diversity, and that degraded components reduce the reliability of the systems, challenge safety systems, and contribute to plant risk. The SRP-LR continues by stating that the effects of aging on a component should be managed to ensure its availability to perform its intended function(s) as designed when called upon, and notes that a program based solely on detecting component failure should not be considered as an effective aging management program for license renewal.
2 Issue:
Based on the information provided in this recent response, as well as the information provided in response to RAI 2.3.3.18-2 for the same issue, the staff did not consider that the applicant has provided sufficient bases to justify the replacement frequency of every seventh refueling outage (approximately 14 years) for the letdown coolers in the makeup and purification system.
The bases for the staff's position are as follows:
a) The applicant established the replacement frequency based on a qualified life, which was empirically derived using two plant-specific data points of 13 and 16 years, after identifying reactor coolant leakage into the component cooling water system.
b) The applicant has not determined the flaw location, performed flaw sizing, or verified flaw characteristics to allow prediction of flaw stability or growth rate.
Without having this information, operation of the letdown cooler with ongoing leakage is risking a failure, which would challenge the pressure relief capability of the component cooling water system and the isolation function of the valves in the makeup and purification system.
c) While past operating experience (although limited) may have shown that the flaw was stable for some period of time, the replacement frequency determination did not appear to consider normal operational pressure transients that the letdown coolers would be expected to experience.
d) The letdown cooler replacement frequency appears to be based on overall calendar time and not actual operational time, considering both refueling and extended outages.
Request:
Provide a letdown cooler replacement frequency that includes adequate margin to initiation of tube leakage and provide the basis for the margin, or propose an aging management program that will adequately manage these components that are within the scope of license renewal.
Discussion:
The NRC staff noted that the basis for the replacement frequency needs to include more information other than the coolers tend to leak after 14 years, so FENOC needs to justify the frequency for replacement or age-manage the coolers. FENOC stated that it appeared that the two possible choices for a response would be to increase the frequency of letdown cooler replacement or to propose an aging management program for the letdown coolers. The NRC staff pointed out that Crystal River is age-managing their coolers, and that they factored-in operational transient information, whereas there was no such information provided by FENOC. The NRC staff stated that, without more details on the basis for the replacement frequency, those were the two apparent choices for a response.
FENOC asked whether the NUREG-1801, Generic Aging Lessons Learned (GALL)
Report, Revision 2, aging management program details for such coolers would be
3 considered appropriate for the Davis-Besse letdown coolers. The NRC staff stated that a program consistent with GALL Revision 2 would be appropriate.
Action:
FENOC to respond to RAI 2.3.3.18-4 in the next license renewal RAI response letter to the NRC (due October 24, 2011). No additional actions.
RAI B.2.22-5 Containment Annulus Area Degradation
Background:
FENOC provided a response to RAI B.2.22-5 regarding management of the containment vessel exterior surface in the annulus area (sand pocket region) by letter dated September 16, 2011 (ML11264A059).
Discussion:
The NRC stated that, based on a review of pictures from a 2010 Condition Report, the moisture barrier on the exterior surface of the containment vessel in the annulus sand pocket area appears to be degraded, as well as the grout and the clear coat. FENOC described the results from inspections of the area performed during the outage currently in progress, which showed that there are three areas of moisture compared to five identified during the previous outage. FENOC stated that the clear coating is 4 feet above the annulus grout-to-vessel interface and is not part of the vessel coating system; the clear coat was applied to protect ultrasonic test markings on the exterior surface of the containment vessel.
The NRC stated that the ASME code requires replacement of the annulus moisture barrier because it is degraded. FENOC stated that the moisture barrier is inspected during outages; however, additional review is needed to respond to whether the ASME code requires replacement or repair of the moisture barrier if degraded.
The NRC stated that the grout in the sand pocket appears to be degraded. FENOC stated that degradation would be addressed by the FENOC Corrective Action Program, and that some degraded areas are planned for repairs during the spring 2012 outage.
The NRC staff stated that the RAI response did not address degradation of the coating of the grout in the annulus. FENOC stated that additional review is needed to respond to that information.
Action:
Hold a follow-up telephone conference call with the NRC to discuss the ASME code requirements for the moisture barrier and the degradation of the coating of the grout in the annulus.
4 RAI B.2.39-9 Refueling Canal Leakage
Background:
FENOC provided a response to RAI B.2.39-9 regarding plans for management of refueling canal leakage effects to concrete and structural steel by letter dated September 16, 2011 (ML11264A059).
Discussion:
NRC questioned the volume of leakage and number of locations of the leakage from the refueling canal. FENOC stated that the specifics for volume and number of locations are not known, but estimated that, based on the size of boric acid deposits, the leakage from the canal could be about 10 gallons over the period during which the refueling canal is filled during a typical outage, and nowhere near the 1,000 gallons per day that was identified at another utility.
The NRC stated that, in the response to RAI B.2.39-9, FENOC had not implemented any of the Sargent & Lundy report recommendations that had been made eight years ago. Additionally, the response states that FENOC claims they will stop the leakage by 2016, but provided no plans to achieve that result. FENOC stated that actions were performed to locate and quantify the leakage in the last outage and are being taken in the current mid-cycle outage. For example, the joints in the canal were coated with a specialty coating, and testing has been performed to attempt to locate leakage paths.
The NRC asked whether FENOC plans to update the Sargent & Lundy report. FENOC stated that the report was a snapshot in time and would not be updated, but that FENOC could document actions taken and quantify the leakage found using the Corrective Action Program.
The NRC stated that the leaking needs to be quantified on the docket. Also, the NRC needs more information regarding leakage reduction actions performed, and information regarding how FENOC knows that there is no current concern with the structural integrity of affected concrete in containment; FENOC needs to make the case on the docket. FENOC stated that additional information would be provided.
The NRC staff stated that, based on the information and pictures contained in Condition Report 10-78984, the corrosion of the supports in the Incore Tunnel appears to be such that the actions taken for boric acid corrosion would not be sufficient to insure that the intended functions of the supports would be maintained throughout the period of extended operation. FENOC stated that the actions taken to address the boric acid corrosion are in accordance with the ongoing Davis-Besse Boric Acid Corrosion Control Program. The program requires that, during each outage, the components are cleaned and repaired as necessary, an as-left inspection is performed, and a comparison of corrosion effects is performed to make a determination as to whether the component can continue to perform its intended function.
Action:
FENOC to provide the NRC with information that quantifies the refueling canal leakage, the history of actions performed to identify and reduce the leakage, and the bases for
5 the conclusions that the structural integrity of the concrete is currently acceptable and will remain acceptable through the period of extended operation.
Draft RAI B.2.40-3
Background:
By letter dated August 17, 2011, the applicant responded to a staff RAI regarding operating experience with degradation of the north embankment of the safety-related portion of the intake canal. In the response the applicant committed to ensure that an investigation of the embankment degradation would be completed prior to the period of extended operation. The applicant further committed to evaluate the results and complete needed repairs or modifications of the embankment prior to the period of extended operation.
Issue:
Although the applicant committed to completing long-term evaluation plans, no information was provided about the plan, such as schedule, scope, or acceptance criteria.
Request:
Provide details about the embankment investigation. The response should include scheduling information, activities planned and completed to date, and probable corrective actions. The response should provide technical justification for the timeliness of the repairs, including an explanation why prior to the period of extended operation is an acceptable deadline for completing the repairs.
Discussion:
The NRC staff asked if there were more details available on the corrective actions for the intake canal embankment addressed in the FENOC response to RAI B.2.40-2.
FENOC responded by describing related work in progress and the action plan for future corrective actions. The NRC staff stated that a follow-up RAI will be sent to FENOC requesting that more detailed information be provided.
Action:
None.
There was no further discussion, and the call was concluded.