ML15082A046

Requests for Additional Information for the Review of the Fermi, Unit 2 License Renewal Application - Set 29,

ML15082A046
Person / Time
Site:	Fermi
Issue date:	03/26/2015
From:	Melendez-Colon D Division of License Renewal
To:	Kaminskas V DTE Electric Company
Melendez-Colon D
References
DLR-15-0164, TAC MF4222
Download: ML15082A046 (7)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 March 26, 2015 Mr. Vito Kaminskas Site Vice President - Nuclear Generation DTE Electric Company Fermi 2 - 280 OBA 6400 North Dixie Highway Newport, MI 48166

SUBJECT:

REQUESTS FOR ADDITIONAL INFORMATION FOR THE REVIEW OF THE FERMI 2 LICENSE RENEWAL APPLICATION - SET 29 (TAC NO. MF4222)

Dear Mr. Kaminskas:

By letter dated April 24, 2014, DTE Electric Company (DTE or the applicant) submitted an application pursuant to Title 10 of the Code of Federal Regulations Part 54, to renew the operating license NPF-43 for Fermi 2, for review by the U.S. Nuclear Regulatory Commission (NRC or the staff). The staff is reviewing the information contained in the license renewal application and has identified, in the enclosure, areas where additional information is needed to complete the review.

These requests for additional information were discussed with Ms. Lynne Goodman, and a mutually agreeable date for the response is within 40 days from the date of this letter. If you have any questions, please contact me at 301-415-3301 or e-mail Daneira.Melendez-Colon@nrc.gov.

Sincerely,

/RA/

Daneira Meléndez-Colón, Project Manager Projects Branch 1 Division of License Renewal Office of Nuclear Reactor Regulation Docket No. 50-341

Enclosure:

Requests for Additional Information cc w/encl: ListServ

ML15082A046 *Concurred via e-mail OFFICE LA:RPB1:DLR PM:RPB1:DLR PM:RPB1:DLR BC:RPB1:DLR PM:RPB1:DLR NAME YEdmonds DMeléndez-Colón JDaily YDíaz-Sanabria DMeléndez-Colón DATE 3/24/15 3/25/15 3/25/15 3/26/15 3/26/15

SUBJECT:

REQUEST FOR ADDITIONAL INFORMATION FOR THE REVIEW OF THE FERMI 2 LICENSE RENEWAL APPLICATION - SET 29 (TAC NO. MF4222)

DISTRIBUTION:

E-MAIL:

PUBLIC RidsNrrDlr Resource RidsNrrDlrRpb1 Resource RidsNrrDlrRpb2 Resource RidsNrrDlrRerb Resource RidsNrrDlrRarb Resource RidsNrrDlrRasb Resource RidsNrrDlrRsrg Resource RidsNrrPMFermi2 Resource

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D. Melendez-Colon Y. Diaz-Sanabria E. Keegan B. Wittick D. McIntyre, OPA B. Harris, OGC D. Roth, OGC M. Kunowski, RIII B. Kemker, RIII V. Mitlyng, RIII P. Chandrathil, RIII C. Lipa, RIII S. Sheldon, RIII

FERMI 2 LICENSE RENEWAL APPLICATION REQUESTS FOR ADDITIONAL INFORMATION SET 29 (TAC NO. MF4222)

RAI B.1.22-2a

Background:

By letter dated December 19, 2014, the staff issued Request for Additional Information (RAI) B.1.22-2 requesting DTE to describe how the Inservice Inspection - IWF Program will continue to be effective when corrective actions are not required per the ASME Code,Section XI, Subsection IWF-2430, but a component in the IWF inspection sample is re-worked such that it no longer represents age-related degradation of the entire population. In response to RAI B.1.22-2 dated January 20, 2015, DTE stated, in part, the following:

Correction of some conditions over the life of the plant is expected but will not impair the ability of the IWF Program to manage the effects of aging. Modifying the program to add new component locations when a condition has been addressed is not necessary. This is because the aging mechanisms will likely be caused by local environment or operational conditions such as vibration or humidity. The programmatic requirements for sample expansion or extent of condition will address that. The Code sample population size is large enough that correction of some conditions will not prevent the program from adequately managing the effects of aging.

Issue:

NUREG-1800, Revision 2, Standard Review Plan for Review of License Renewal Applications for Nuclear Power Plants (SRP-LR), Appendix A.1, recommends that when sampling is used to represent a larger population of components the sample should be based on aspects such as similarity of material, environment, and specific aging effect. The staff concern is that re-worked to as new condition IWF components are no longer representative of the specific age-related degradation of those IWF components in the population that are not in the inspection sample.

Request:

Explain how the Inservice Inspection - IWF Program will ensure that the inspection sample will adequately represent the age-related degradation of the IWF component population when components that are part of the sample are re-worked and no longer represent the age-related degradation of the remaining population.

RAI 3.2.2.2-1a

Background:

By letter dated February 5, 2015, DTE responded to an initial RAI regarding spray nozzles in the reactor heat removal (RHR) system, which are being managed by the Water Chemistry - BWR ENCLOSURE

Program. For the drywell spray headers, the response confirms that the portions inside the drywell are not safety-related and there is no flow control function for the associated spray nozzles. For the suppression chamber spray nozzles, the response states that the suppression pool is inerted to less than 4 percent oxygen during power operation which reduces the potential for corrosion. The response also describes the quarterly surveillance test on the suppression chamber spray system and states that greater-than-minimum flow rates were achieved during every surveillance test for the last 4 years. The response also states that if significant blockage were to develop, the flow rates through the suppression chamber spray header would indicate a decreasing trend. In addition, the response describes the 5-year surveillance test that verifies the drywell spray nozzles are unobstructed. With respect to aging management activities for the suppression chamber piping and spray nozzles, the response states that the One-Time Inspection Program will confirm the effectiveness of the Water Chemistry - BWR Program and that the internal environment of the spray header is considered treated water. The response concludes that the license renewal application (LRA) did not need to be revised.

Issue:

As noted in the initial RAI, the LRA defines flow control as provide control of flow rate or establish a pattern of spray. The RHR system spray nozzles in LRA Table 3.2.2-2, which show an intended function of flow control, only list loss of material as the aging effect requiring management. While the staff recognizes that loss of material in a spray nozzle may affect its spray pattern, loss of material would only tend to allow higher flow rates, and the RAI response does not include any discussion regarding activities to monitor nozzle spray patterns. Verifying the total flow into the suppression chamber does not confirm flow control for individual nozzles.

Based on the RAI response, it remains unclear to the staff how only managing loss of material will address the flow control function for individual spray nozzles due to potential plugging from corrosion products. The staff notes that for other aging management review (AMR) items, the LRA includes fouling as an aging effect requiring management, while the Generic Aging Lessons Learned (GALL) Report considers fouling as an aging mechanism. As it relates to nozzle plugging, the staff considers fouling to be an appropriate aging effect.

The staff notes that containment inerting to less than 4 percent oxygen appears to be the only basis provided in the RAI response that relates to a lack of corrosion product accumulation due to periodic wetting and drying of upstream steel piping. Although the inerted atmosphere may reduce the amount of corrosion, the staff concludes that there is still sufficient oxygen to support ongoing general corrosion in the steel piping upstream of the nozzles. In addition, a relatively low level of oxygen in the water within the system is sufficient to cause ongoing corrosion issues within the suppression pool or attached steel piping. The staff notes the operating experience included in the Fitzpatrick license renewal safety evaluation report (ADAMS Accession No.

ML080250372) discusses blockage in some spray nozzles found during past surveillance tests.

Based on the above, the response did not provide sufficient bases to establish that corrosion product accumulation from upstream steel piping cannot cause flow blockage in the suppression chamber nozzles.

In its review of the response, the staff notes that blockage for the suppression chamber spray nozzles is to some degree being managed through various surveillance activities. However, the only program credited in the LRA for the nozzles is the Water Chemistry Control - BWR

Program, which does not include these surveillance activities. In addition, activities in the One-Time Inspection Program to confirm the effectiveness of the Water Chemistry Control -

BWR Program, only include fouling as it relates to reduction of heat transfer and do not address fouling as it relates to plugging of spray nozzles.

The staff also notes that the One-Time Inspection Program currently includes inspections of internal and external surfaces of the piping in several systems that pass through the waterline region of the suppression pool. However, neither the suppression pool spray piping nor the spray nozzles are included in those activities. In that regard, the internal surfaces of the suppression pool spray piping are different than most other piping surfaces because they are periodically wetted during surveillance activities, but portions of the system will drain between tests and the inside surfaces will be exposed to the suppression pool atmosphere.

Consequently, it is not clear to the staff whether the suppression pool spray header piping will be considered as a unique internal environment from other piping that remains filled with treated water. As discussed in NRC Information Notice 2013-06, Corrosion in Fire Protection Piping Due to Air and Water Interaction, piping systems filled with water or kept completely dry are not as susceptible to internal corrosion as piping partially filled with water and air; however, even a properly designed system is susceptible to corrosion when it is filled with water numerous times because of testing. The staff acknowledges that this information notice only addressed fire water system piping, but there may be some commonality with potential problems in the suppression pool spray piping.

If the current suppression chamber spray header surveillances will be credited, then several additional aspects may need to be addressed. Although the initial RAI response states that a decreasing trend in the suppression chamber spray header flow rate would indicate the development of flow blockage, it is not clear to the staff that the current surveillance activities include trending of the spray header flow rates in order to identify this type of degradation. In addition, it is not clear to the staff that only trending of the flow rate through the spray header would be sufficient to identify flow blockage. Unless individual spray nozzles are being verified to be unobstructed (which, based on DTEs RAI response, is performed for the nonsafety-related drywell spray nozzles that do not require aging management), it is not clear to the staff how other activities can demonstrate that the effects of aging will be adequately managed so that the flow control intended function of the spray nozzles will be maintained during the period of extended operation, consistent with the current licensing basis.

Request:

1. Provide the bases to demonstrate that fouling does not need to be managed for the suppression chamber spray nozzles in order to adequately maintain the flow control intended function of the spray nozzles during the period of extended operation, consistent with the current licensing basis. As an alternative, provide an appropriate AMR item that addresses the aging effects associated with the spray nozzle flow control intended function. If applicable, include a description of the associated aging management activities that are either an enhancement to an existing program or a plant-specific aging management program. If flow rate is the only parameter that will be monitored, provide the acceptance criteria for the flow rate trend with supporting bases to demonstrate that the intended function

of the spray nozzles will be maintained during the period of extended operation, consistent with the current licensing basis.

2. Confirm that the environment for the internal surfaces of the suppression chamber spray piping will be considered as a different internal environment from other normally-filled treated water piping within the One-Time Inspection Program, or provide the bases to demonstrate that such a distinction is not needed for the portion of piping that is periodically wetted and drained.