ML102600340

RAI for Salem Nuclear Generating Station Units 1 and 2 License Renewal Application for Buried Piping Inspection Program (TAC No. ME1834 and ME1836)

ML102600340
Person / Time
Site:	Salem
Issue date:	10/12/2010
From:	Bennett Brady License Renewal Projects Branch 1
To:	Joyce T Public Service Enterprise Group
Samuel Cuadrado-De Jesus, 415-2946
References
TAC ME1834, TAC ME1836
Download: ML102600340 (7)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555*0001 October 12,2010 Mr. Thomas Joyce President and Chief Nuclear Officer PSEG Nuclear LLC P.O. Box 236 Hancocks Bridge, NJ 08038

SUBJECT:

REQUEST FOR ADDITIONAL INFORMATION FOR SALEM NUCLEAR GENERATING STATION, UNITS 1 AND 2, LICENSE RENEWAL APPLICATION FOR BURIED PIPING INSPECTION PROGRAM (TAC NOS. ME1834 AND ME 1836)

Dear Mr. Joyce:

By letter dated August 18, 2009, Public Service Enterprise Group Nuclear, LLC, submitted an application pursuant to Title 10 of the Gode of Federal Regulations, Part 54 for renewal of Operating License Nos. DPR-70 and DPR-75 for Salem Nuclear Generating Station, Units 1 and 2, respectively. The staff of the U.S. Nuclear Regulatory Commission (NRC or the staff) is reviewing this application in accordance with the guidance in NUREG-1800, "Standard Review Plan for Review of License Renewal Applications for Nuclear Power Plants." During its review, the staff has identified areas where additional information is needed to complete the review.

The staff's request for additional information is included in the Enclosure. Further requests for additional information may be issued in the future.

Items in the enclosure were provided to John Hufnagel and other members of your staff, and a mutually agreeable date for the response is within 30 days from the date of this letter. If you have any questions, please contact me by telephone at 301-415-2981 or bye-mail at bennett. brady@nrc.gov.

Sincerely, Bennett M. Brady, Project Manager Projects Branch 1 DiviSion of License Renewal Office of Nuclear Reactor Regulation Docket Nos. 50-272 and 50-311

Enclosure:

As stated cc w/encl: Distribution via Listserv

REQUEST FOR ADDITIONAL INFORMATION FOR SALEM NUCLEAR GENERATING STATION, UNITS 1 AND 2 LICENSE RENEWAL APPLICATION FOR BURIED PIPING INSPECTION PROGRAM (TAC NOS. ME1834 AND ME1836)

RAI B.2.1.22-02 Follow-up to RAI B.2.1.22

Background:

Given that there have been a number of recent industry events involving leakage from buried or underground piping, the staff required further information to evaluate the impact that these recent industry events might have on the applicant's Buried Piping Inspection and Buried Non Steel Piping Inspection Programs. By letter dated August 6, 2010, the staff issued RAI B.2.1.22 requesting that the applicant provide information regarding how Salem will incorporate the recent industry operating experience into its aging management reviews and programs. The applicant responded on September 7,2010. In reviewing the response, the staff had further questions.

Issue:

a) The applicant's response stated that "Planned direct visual inspections of excavated piping typically include the entire circumference and a length of approximately eight feet (based on a standard shoring box size), when practical." The staff does not have enough information to evaluate the statement, "when practical." While the staff acknowledges that examining buried pipe from the exterior surface may sometimes not be possible due to plant configuration (e.g., the piping is located underneath foundations); nevertheless, it is important to expose a large enough length of the piping in order to establish reasonable assurance of the condition of the piping system. The staff believes that in instances where it is not possible to expose eight feet of piping during each inspection, an alternative examination should be proposed. The staff notes that it is reasonable to substitute an ultrasonic volumetric examination from the interior of the pipe provided the surface is properly prepared.

b) The applicant's response stated that, "Salem Units 1 and 2 buried piping systems do not have cathodic protection installed. None of the seven above systems within the scope for license renewal have dedicated cathodic protection systems. The lack of cathodic protection is an input to the risk ranking methodology." The staff believes that cathodic protection is an important preventive measure for steel piping. The staff notes that there have been several instances where coating failures have occurred or specified coatings have not been installed, resulting in either leakage occurring or pipe minimum wall thicknesses being challenged, examples include:

i. From the LRA, "In 2001, a section of the buried No. 12 service water piping at Salem Unit 1 was excavated to determine the cause of leakage. The source of leakage was a break in the steel bell ring, which is installed over one pipe joint section of the service water piping. The apparent cause of the break was a crack ENCLOSURE

- 2 that occurred during the installation of the steel bell ring or an initial flaw in the metal. Additionally, the metal and mortar was cracked in about the same area, which could indicate that this area was cracked at installation. Contributing to the growth of the initial crack and subsequent corrosion of the steel bell ring was improper protection of the carbon steel bell ring on the underground service water buried pipe joint. Therefore the apparent cause of the failure was an installation flaw and improper coating protection of the joint and not an age related failure mechanism."

ii. From the LRA, "In 2004, buried carbon steel piping in the Salem Unit 1 fuel oil system was excavated to repair leakage at a welded joint. The socket-welded joint was not properly wrapped with a protective tape. The wrap for this joint was originally missing altogether and the leakage was caused by direct exposure to groundwater and subsequent corrosion, not by aging."

iii. In the RAI response, the applicant stated an example from 2010 where it was determined that a significant portion of the Unit 1 buried auxiliary feedwater (AFW) system piping had it's coating inadvertently removed during construction.

This resulted in areas of the piping degrading, although all degraded portions were determined to be operable after re-analysis.

iv. In the RAI response, the applicant stated an example from 2010, "A small pipe leak was found on a 1-inch Control Air System pipe buried in sand in the Fuel Transfer Tube Area. The through wall leak was located at a location where the protective coating on an elbow was damaged. The apparent cause of the coating damage was that personnel previously stepped on the pipe thus damaging the coating."

The staff believes that cathodic protection is an important preventive measure for steel piping where soil resistivity values are below 20,000 ohm cm. The staff also believes that an acceptable alternative to protecting steel piping with a cathodic protection system is to demonstrate, that actual corrosion rates are low enough such that minimum design wall thickness for the buried pipe will not be reached within the period of extended operation. The staff notes that the analyses that accompanied the buried pipe inspections of the Unit 1 AFW system demonstrated that the pipe wall as-found conditions were determined to meet operability limits; however, the staff lacks sufficient information to determine if the minimum design wall thickness would have been met through the period of extended operation. The staff also notes that the applicant, givenrecent operating experience, has proposed to perform three additional opportunistic or focused excavations and direct inspections of carbon steel piping and components during each ten year period commencing ten years prior to the period of extended operation.

c) Given that the non-radioactive drain system, as stated in LRA Section 2.3.3.18, interfaces with areas such as the diesel generator sump, fuel handling building, refueling water storage tank pipe tunnel, and sump piping that ends at the interface with the Unit 2 radwaste system, the staff does not have enough information to determine if the non-radioactive drain system contains hazardous material during normal operation (i.e., material which, if released, could be detrimental to the environment such as diesel

-3 fuel and radioisotopes that exceed EPA drinking water standards). The staff believes that there is a minimum set of excavated and visual inspections of buried piping segments that contain hazardous materials that should be conducted to establish a reasonable basis of assurance that aging effects are not adversely impacting buried pipe and resulting in the release of hazardous materials to the environment.

d) Neither the LRA nor RAI response described the quality of the backfill in the vicinity of buried in-scope piping. The staff understands that the presence of rocks and sharp objects in the backfill around buried pipes is a leading precursor of degradation of buried piping when over time; ground movement causes these materials to come in contact with the buried pipe resulting in damage to the pipe's coating or external surfaces.

Request:

a) Define what is meant by "when practical" in relation to the length of piping being excavated for inspection. Additionally, where it is not practical to excavate and inspect eight feet of piping for each inspection, state what alternative means will be utilized to determine the condition of the piping material, or justify why inspecting less than eight feet of piping in the context of all planned inspections for each discrete material type provides a reasonable assurance of the condition of the buried pipe and coatings where applicable.

b) For buried in-scope steel piping respond to the following:

i. Provide sufficient detail for the staff to determine that the site soil resistivity in the vicinity of all buried steel pipe exceeds 20,000 ohm cm and if this is the case, explain why the corrosion on the AFW system occurred to such a degree as was observed during inspections, or ii. Provide sufficient detail for the staff to determine that all buried in-scope steel piping will meet or exceed the minimum design wall thickness throughout the period of extended operation assuming that no coatings are applied to the piping, or iii. Justify why the inspections that have been conducted, and the proposed four inspections of steel piping in each ten year period commencing ten years prior to the period of extended operation, are sufficient to determine the extent of condition of miSSing or damaged coatings, before any buried in-scope steel piping segment will not meet the minimum design wall thickness throughout the period of extended operation.

c) For buried in-scope piping respond to the following:

i. Does the non-radioactive drain system contain hazardous material during normal operation?

-4 ii. If the non-radioactive drain system contains hazardous material during normal operation, state what percent of total linear feet of buried in-scope non radioactive drain system piping, will be inspected by excavation and direct inspection, during each ten year period starting ten years prior to the period of extended operation. If there are no planned inspections for this piping, justify why it is acceptable to not inspect in-scope buried pipe containing hazardous materials.

d) For buried in-scope piping respond to the following:

i. Provide details on the quality of the backfill in the vicinity of in-scope buried pipes.

ii. If there is no information on the condition of the quality of backfill beyond initial installation specifications (Le., no documented observations of the quality of the backfill), justify why the planned inspections are adequate to detect potential pipe degradation as a result of coating damage or holidays, or damage to the exterior surface of non-coated piping.

'.. ML102600340 OFFICE PM:DLR:RPB1 LA:DLR BC:DLR:RPB1 PM:DLR:RPB1 NAME B. Brady YEdmonds B. Pham B. Brady DATE 10/7/10 9123/10 10/12110 10/12110

Letter to T. Joyce from B. Brady dated October 12,2010

SUBJECT:

REQUEST FOR ADDITIONAL INFORMATION FOR SALEM NUCLEAR GENERATING STATION UNITS 1 AND 2 LICENSE RENEWAL APPLICATION FOR BURIED PIPING INSPECTION PROGRAM (TAC NOS. ME1834 AND ME 1836)

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