ML14246A069

Relief Request RR-ISI-04-08, Revision 1, Request for Relief Using Alternative Repair for Buried Saltwater Piping (Tac Nos. MF3413 and MF3414)

ML14246A069
Person / Time
Site:	Calvert Cliffs
Issue date:	12/19/2014
From:	Benjamin Beasley Plant Licensing Branch 1
To:	George Gellrich Calvert Cliffs
Morgan N
References
TAC MF3413, TAC MF3414
Download: ML14246A069 (11)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 December 19, 2014 Mr. George H. Gellrich, Vice President Calvert Cliffs Nuclear Power Plant, LLC Calvert Cliffs Nuclear Power Plant 1650 Calvert Cliffs Parkway Lusby, MD 20657-4702

SUBJECT:

CALVERT CLIFFS NUCLEAR POWER PLANT, UNITS 1 AND 2- RELIEF REQUEST RR-ISI-04-08, REVISION 1, REGARDING MITIGATION OF BURIED SALTWATER PIPING DEGRADATION (TAC NOS. MF3413AND MF3414)

Dear Mr. Gellrich:

By letter dated January 29, 2014, as supplemented by letter dated February 14, 2014, Calvert Cliffs Nuclear Power Plant, LLC (the licensee), submitted to the Nuclear Regulatory Commission (NRC) relief request RR-ISI-04-08, Revision 1, for authorization of a proposed alternative to certain requirements of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code),Section XI, Article IWA-4000, for Calvert Cliffs Nuclear Power Plant, Units 1 and 2 (Calvert Cliffs).

Specifically, the licensee proposed to use a mechanical sleeve assembly to repair inside surface degradation of mortar lined ductile iron piping in the saltwater system for the remainder of the Calvert Cliffs fourth 10-year inservice inspection (lSI) interval. Pursuant to Title 10 of the Code of Federal Regulations (1 0 CFR), Section 50.55a(a)(3)(ii), the licensee requested to use the proposed alternative on the basis that complying with the specified ASME Code requirement would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety.

The NRC staff has determined that the licensee's proposed alternative provided reasonable assurance of structural integrity or leak tightness of the subject component, and that complying with the specified requirement would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety. Accordingly, the NRC staff has concluded that the licensee has adequately addressed all of the regulatory requirements set forth in 10 CFR 50.55a(a)(3)(ii). Therefore, the NRC staff authorizes the use of the licensee's proposed alternative in relief request RR-ISI-04-08, Revision 1, for the remainder of the fourth 10-year lSI interval, which ends on June 30, 2019, for Calvert Cliffs.

All other ASME Code,Section XI requirements for which relief was not specifically requested and approved in the subject request for relief remain applicable, including the third party review by the Authorized Nuclear lnservice Inspector.

G. Gellrich On February 25, 2014, the NRC staff granted verbal authorization of the licensee's proposed alternative in relief request RR-ISI-04-08, Revision 1. The enclosed safety evaluation documents the NRC staff's review and technical basis for this authorization.

If you have any questions, please contact the Calvert Cliffs Project Manager, Nadiyah Morgan, at (301) 415-1016, or by e-mail at Nadiyah.Morgan@nrc.gov.

Sincerely, Benjamin G. Beasley, Chief Plant Licensing Branch 1-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-317 and 50-318

Enclosure:

Safety Evaluation cc w/enclosure: Distribution via Listserv

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELIEF REQUEST RR-ISI-04-08, REVISION 1, REGARDING MITIGATION OF BURIED SALTWATER PIPING DEGRADATION CALVERT CLIFFS NUCLEAR POWER PLANT, LLC EXELON GENERATION COMPANY, LLC CALVERT CLIFFS NUCLEAR POWER PLANT, UNITS 1 AND 2 DOCKET NOS. 50-317 AND 50-318

1.0 INTRODUCTION

By letter dated January 29, 2014 (Agencywide Documents and Access Management System (ADAMS) Accession No. ML14034A173), as supplemented by letter dated February 14, 2014 (ADAMS Accession No. ML14050A127), Calvert Cliffs Nuclear Power Plant, LLC (the licensee),

submitted relief request RR-ISI-04-08, Revision 1, for authorization of a proposed alternative to certain requirements of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code),Section XI, Article IWA-4000, for Calvert Cliffs Nuclear Power Plant, Units 1 and 2 (Calvert Cliffs).

Specifically, the licensee proposed to use a mechanical sleeve assembly to repair inside surface degradation of mortar lined ductile iron piping in the saltwater system for the remainder of the Calvert Cliffs' fourth 10-year inservice inspection (lSI) interval. Pursuant to Title 10 of the Code of Federal Regulations (1 0 CFR), Section 50.55a(a)(3)(ii), the licensee requested to use the proposed alternative on the basis that complying with the specified ASME Code requirement would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety.

On February 25, 2014 (ADAMS Accession No. ML14055A213), the U.S .. Nuclear Regulatory Commission (NRC) staff granted verbal authorization of the licensee's proposed alternative in relief request RR-ISI-04-08, Revision 1. This safety evaluation documents the NRC staff's review and technical basis for this authorization.

2.0 BACKGROUND

By letter dated January 17, 2013 (ADAMS Accession No. ML13022A048), as supplemented by letter dated May 17, 2013 (ADAMS Accession No. ML13141A270), the licensee submitted relief request RR-ISI-04-08 for authorization of a proposed alternative to use metal reinforced polymeric Enclosure

patches to address inside diameter degradation of mortar lined ductile iron piping in the saltwater system. By letter dated November 13, 2013 (ADAMS Accession No. ML13297A293), the NRC staff authorized the proposed alternative. Subsequently, the licensee submitted relief request RR-ISI-04-08, Revision 1, to correct the design temperature of the saltwater system used in the stress calculation and to add a specific statement that mentions that the installation of the mechanical sleeve assembly is applicable to joints within the buried saltwater system piping.

3.0 REGULATORY EVALUATION

In relief request RR-ISI-04-08, Revision 1, the licensee requests authorization of an alternative to the requirements of the ASME Code,Section XI, Article IWA-4000 pursuant to 10 CFR 55a(a)(3)(ii).

Adherence to Article IWA-4000 of Section XI of the ASME Code is mandated by 10 CFR 50.55a(g)(4), which states, in part, that ASME Code Class 1, 2, and 3 components (including supports) will meet the requirements, except the design and access provisions and the preservice examination requirements set forth in the ASME Code,Section XI.

The regulations at 10 CFR 50.55a(a)(3) state, in part, that alternatives to the requirements of paragraph (g) of 10 CFR 50.55a may be used, when authorized by the NRC, if the licensee demonstrates that: (i) the proposed alternative provides an acceptable level of quality and safety, or (ii) compliance with the specified requirements would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety.

Based on the above, and subject to the following technical evaluation, the NRC staff finds that regulatory authority exists for the licensee to request the use of an alternative and the NRC to authorize the proposed alternative.

4.0 TECHNICAL EVALUATION

4.1 RR-ISI-04-08. Revision 1 For the most part, relief request RR-ISI-04-08, Revision 1, is consistent with the relief request RR-ISI-04-08, except for the following significant changes with corresponding sections and page numbers.

Change #1: Section 5, Page 2, the licensee added the following new requirement:

The supporting calculation ... states any repairs are made in straight lengths of pipe. This includes the bell and spigot joints that are part of straight lengths of pipe within the Saltwater System. The proposed repair alternative is not designed to be used in pipe elbows or across mitered joints.

Using the proposed alternative to repair bell and spigot joints, the licensee stated in its February 14, 2014 letter:

The pipe joint consists of a bell and spigot configuration with fittings that connect to compress the joint gasket. Bolting between the gland and the bell provides a leak tight joint and also develops a friction fit to inhibit differential axial or rotational pipe movement.

The licensee also stated in part that:

In an unrepaired joint, a small gap in the concrete pipe lining exists across the bell and spigot joint to allow for limited movement between the pipe segments.

Absence of such a gap would result in cracking of the concrete liner. For the same reason, in a repaired joint, a similar gap will be left between pipe segments when the sealant is applied.

Relative motion across the bell and spigot joint due to temperature variations, moisture variations or seismic activity is expected to be very small. This expected lack of relative motion is due to, in part, the fact that the subject pipe is located under the North Service Building and Turbine Building. The location of the subject piping relative to these structures is expected to substantially restrict relative motion of piping segments by constraining the fill in which the subject pipe is located. Additionally, there are concrete thrust barriers installed at each elbow where a straight pipe changes directions. These concrete thrust barriers further prevent any relative movement of the pipe in the axial direction.

Water is prevented from reaching the joint by the Ethylene Propylene Diene Monomer (EPDM gasket). This gasket is flexible so it can accommodate the small amount of relative motion expected between pipe segments. The EPDM gasket is held in place firmly by retaining bands located at each end; minor relative motion between the pipe segments will not affect the retaining bands and, therefore, will not cause the gasket to leak. Therefore, corrosion of the backing plate and other joint components is not expected. Likewise, due to the flexibility of the gasket and the manner in which it is retained against the pipe, relative motion across the pipe joint is not expected to dislodge or tear the gasket so that it could potentially foul downstream components.

Change #2: Section 5, Page 2, the licensee added the following new requirement:

The buried saltwater piping has a design pressure of 50 psig [pounds per square inch gauge]. The Saltwater System temperature varies in accordance with Chesapeake Bay temperature throughout the year and load demands on the system. The Saltwater System is exposed to temperatures from 30 oF [degrees Fahrenheit] up to its design temperature of 200 °F.

The licensee revised the stress calculation by using a design temperature of 200 oF.

Change #3: Section 7, Page 4, the licensee revised the text of RR-ISI-04-08:

From:

Prior to installation of the sleeve, the cement coating of the degraded area and its surrounding area will be removed and repaired with an approved sealant.

To:

Prior to installation of the sleeve, the cement lining for the entire length of the sleeve assembly will be removed and repaired with an approved sealant.

Regarding the installation of sealant, in its February 14, 2014 letter, the licensee stated in part that:

1. The sealant that will be used is a paste grade. It is used for filling degraded ductile and cast iron pipe back to its original contours. It provides erosion and corrosion resistance to the metal surfaces. The sealant will be applied to provide a smooth, continuous surface, which will allow good contact with other components of the repair.

2. The sealant and coating materials have been used in many applications in the saltwater system since 1992.

3. The sealant and coating material were qualified for the saltwater system design conditions and in accordance with the American Society for Testing and Materials tests performed by the manufacturer (per the material's specification sheets).

4. The sealant and coating were not qualified for a specific service life.

However, they have been used for over 20 years in the licensee's saltwater system piping. Inspections of the materials have revealed no significant degradation.

Change #4: Section 7, Page 6, the licensee revised the text of RR-ISI-04-08:

From:

This proposed repair system will not be used in cases of discovered cracking or on corrosion that initiated on the external diameter of the saltwater piping.

To:

This proposed repair system will not be used in cases of discovered crack like flaws, through wall degradation, or on corrosion that initiated on the external diameter of the saltwater piping.

The licensee noted that by making a limitation which precludes the use of the alternative for instances in which through-wall leakage is occurring, corrosion of the repair due to water ingress from outside the pipe need not be considered.

Change #5: Section 7, page 8, the licensee revised the text of RR-ISI-0-08:

From:

• A check of the retaining bands and backing ring for corrosion

• A check of the liner under the sleeve for wetness

• A check for any damage of the liner To:

• A check of the retaining bands and backing ring for corrosion

• A check of the area under the sleeve for wetness

• A check for any damage of the liner

• A check for damage of the EPDM gasket The licensee added additional steps in the examination after the sleeve is installed.

Change #6: Section 7, Page 8, the licensee revised the text of RR-ISI-04-08:

From:

Defects where the repair system is utilized will be characterized and projections on growth will be provided to ensure that the defect will be contained within the specified limits of the repair system.

To:

Defects where the repair system is utilized will be characterized to ensure that the defect will be contained within the specified limits of the repair system.

The licensee deleted the crack growth projections.

Change #7: The licensee added the following commitments in RR-ISI-04-08, Revision 1:

After Unit 1 RFO [refueling outage], establish a work order to inspect one installed Saltwater System sleeve assembly approved in RR-ISI-04-08, Revision 1, after two operating cycles. If no sleeve assembly installed during RFO, no action required. Create a new action item for subsequent Unit 1 RFO if Saltwater System piping inspection to be conducted. Date -

May 1, 2014.

After Unit 2 RFO, establish a work order to inspect one installed Saltwater System sleeve assembly approved in RR-ISI-04-08, Revision 1, after two operating cycles. If no sleeve assembly installed during RFO, no action required.

Create a new action item for subsequent Unit 2 RFO if Saltwater System piping inspection to be conducted. Date - May 1, 2015.

The licensee indicated that any additional repair system installed will be visually inspected every other refueling outage. The licensee noted that because the proposed alternative will only be implemented when applicable degraded conditions are identified during future inspections, the intent of the two commitments was to ensure that the disassembly of the first installed sleeve assembly is tracked regardless of whether it was installed on Unit 1 or Unit 2. The licensee explained that the purpose of the commitments was not meant to disassemble the first installed sleeve assembly on each unit.

4.2 NRC Staff Evaluation The NRC staff evaluated the design, examinations, analysis, pressure tests, and hardship justification of the proposed repair method in relief request RR-ISI-04-08, as documented in its safety evaluation dated November 13, 2013. Therefore, for relief request RR-ISI-04-08, Revision 1, the purpose of the NRC staff's review is not to repeat the review of the proposed alternative, but to evaluate the above changes with respect to the original relief request RR-ISI-04-08.

4.2.1 Change #1 -The Repair of the Bell and Spigot Joint The NRC staff evaluated the concept of using the proposed alternative to repair bell and spigot joints. The NRC staff notes that the potential for relative motion between the two pipe sections to be the significant difference in using the proposed alternative to repair pipe joints as compared to the previously approved use of the proposed alternative to repair pipe segments.

The NRC staff also notes that, as in the case of the "as designed" joint, no rigid material will be applied across the joint which would be damaged by relative motion between the two pipe segments. The NRC staff has determined that relative motion between pipe segments will be minimized as a result of the location of that piping relative to other structures. The NRC staff has also determined that the EPDM gasket is sufficiently flexible to maintain the necessary seal and not become dislodged due to relative motion between pipe segments. Therefore, the NRC staff finds this change to the proposed alternative to be acceptable.

4.2.2 Change #2- Change in Design Temperature The NRC staff notes that the licensee has revised its stress calculations using a design temperature of 200 °F. The licensee's revised calculation shows that the sleeve components will be within the allowable stresses, based on a design temperature of 200 °F. Therefore, the NRC staff finds this change to be acceptable.

4.2.3 Change #3- Removal of Cement Lining The NRC staff reviewed the extent to which concrete lining will be removed from the pipe and the sealant material which will be installed. The NRC staff has determined that the extent to which the concrete lining will be removed from the pipe is sufficient to ensure an adequate surface over which the EPDM gasket can be applied. The NRC staff has also determined that the qualification and expected service life of the sealant are reasonable for the sealant's intended purpose. Therefore, the NRC staff finds this change to the proposed alternative to be acceptable.

4.2.4 Change #4- Limitation on Application The NRC staff reviewed the additional limitation on the applicability of the proposed alternative.

The proposed alternative will not be used in cases of through-wall leakage. The NRC staff has determined that this limitation is appropriate, because this limitation obviates the need to consider the ingress of water into the repair from the outside of the repair. Since the repair is not designed to prevent the entry of water into the repair from the outside, the NRC has determined that this limitation is both necessary and sufficient to protect the repair from water intrusion. Therefore, the NRC staff finds this change to the proposed alternative to be acceptable.

4.2.5 Change #5- Inspection Procedures The NRC staff reviewed the additional steps which the licensee added to the inspection procedures. The NRC has determined that the additional steps will reduce the possibility that degradation of the repair would not be identified during a scheduled inspection. Therefore, the NRC staff finds this change to the proposed alternative to be acceptable.

4.2.6 Change #6- Projection of Defect Growth The NRC staff has no objections to the deletion of "projections on growth will be provided" because neither the ASME Code,Section XI, nor 10 CFR 50.55a, requires licensees to submit defect growth projections regarding ASME Code Class 3 piping. However, while the licensee is not required to submit these projections to the NRC, the NRC staff notes that these projections are necessary to ensure the adequacy of the repair and, therefore, must be made and appropriately documented. The NRC staff finds this change to the proposed alternative to be acceptable.

4.2.7 Change# 7- Regulatory Commitments The NRC staff reviewed the regulatory commitments and finds these commitments to be technically acceptable.

5.0 CONCLUSION

As set forth above, and in conjunction with the its November 13, 2013, safety evaluation for RR-ISI-04-08, the NRC staff has determined that the licensee's proposed alternative provided reasonable assurance of structural integrity or leak tightness of the subject component, and that complying with the specified requirement would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety. Accordingly, the NRC staff had concluded that the licensee has adequately addressed all of the regulatory requirements set forth in 10 CFR 50.55a(a)(3)(ii). Therefore, the NRC staff authorizes the use of the licensee's proposed alternative in relief request RR-ISI-04-08, Revision 1, for the remainder of the fourth 10-year lSI interval, which ends on June 30, 2019 for Calvert Cliffs.

All other ASME Code,Section XI requirements for which relief has not been specifically requested and approved in this relief request remain applicable, including third party review by the Authorized Nuclear lnservice Inspector.

Principal Contributor: John Tsao Date: December 19, 2014

G. Gellrich On February 25, 2014, the NRC staff granted verbal authorization of the licensee's proposed alternative in relief request RR-ISI-04-08, Revision 1. The enclosed safety evaluation documents the NRC staff's review and technical basis for this authorization.

If you have any questions, please contact the Calvert Cliffs Project Manager, Nadiyah Morgan, at (301) 415-1016, or by e-mail at Nadiyah.Morgan@nrc.gov.

Sincerely, IRA/

Benjamin G. Beasley, Chief Plant Licensing Branch 1-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-317 and 50-318

Enclosure:

Safety Evaluation cc w/enclosure: Distribution via Listserv DISTRIBUTION:

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