ML17124A303

Proposed Alternative to Utilize Code Case N-789-1, Alternative Requirements for Pad Reinforcement of Class 2 and 3 Moderate-Energy Carbon Steel Piping for Raw Water Service,Section XI, Division 1

ML17124A303
Person / Time
Site:	FitzPatrick
Issue date:	05/04/2017
From:	Jim Barstow Exelon Generation Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
Download: ML17124A303 (6)

Text

Exelon Generation.n 200 Exelon Way Kennett Square, PA 19348 www.exeloncorp.com 10 CFR 50.55a May4, 2017 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001 James A. FitzPatrick Nuclear Power Plant Renewed Facility Operating License No. DPR-59 NRC Docket No. 50-333

Subject:

Proposed Alternative to Utilize Code Case N-789-1, "Alternative Requirements for Pad Reinforcement of Class 2 and 3 Moderate-Energy Carbon Steel Piping for Raw Water Service,Section XI, Division 1"

References:

1) Letter from G. Miller (U.S. Nuclear Regulatory Commission) to B. Hanson (Exelon Generation Company, LLC), "Calvert Cliffs Nuclear Power Plant, Units 1 and 2; Nine Mile Point Nuclear Station, Units 1 and 2; and R.E.

Ginna Nuclear Power Plant - Proposed Alternative to Use Code Case N-789 (CAC Nos. MF7018 - MF77022)," dated May 19, 2016 (ML16138A021)

2) Letter from J. Barstow (Exelon Generation Company, LLC) to U.S.

Nuclear Regulatory Commission, "Proposed Alternative to Utilize Code Case N-789, 'Alternative Requirements for Pad Reinforcement of Class 2 and 3 Moderate-Energy Carbon Steel Piping for Raw Water Service,Section XI, Division 1'," dated March 22, 2016 (ML16083A412)

3) Letter from J. Barstow (Exelon Generation Company, LLC) to U.S.

Nuclear Regulatory Commission, "Proposed Alternative to Utilize Code Case N-789, 'Alternative Requirements for Pad Reinforcement of Class 2 and 3 Moderate-Energy Carbon Steel Piping tor Raw Water Service,Section XI, Division 1'," dated October 28, 2015 (ML15301A596)

4) Letter from J. Zimmerman (U.S. Nuclear Regulatory Commission) to M. Pacilio (Exelon Generation Company, LLC), Request to Use American Society of Mechanical Engineers Boiler and Pressure Vessel Code Case N-789, "Alternative Requirements for PAD Reinforcement of Class 2 and 3 Moderate-Energy Carbon Steel Piping for Raw Water Service,Section XI, Division 1," dated May 10, 2012(ML12121A637)

Proposed Alternative to Utilize Code Case N-789-1 May 4, 2017 Page2

5) Letter from T. Tate (U.S. Nuclear Regulatory Commission) to J. Mccann (Entergy Services, Inc.), Relief Request RR-EN-15-1, Proposed Alternative to Use American Society of Mechanical Engineers Boiler and Pressure Vessel Code Case N-789-1, "Alternative Requirements for Pad Reinforcement of Class 2 and 3 Moderate Energy Carbon Steel Piping for Raw Water Service,Section XI, Division 1" (CAC Nos. MF6340, MF6341, MF6342, MF6343, MF6344, MF6345, MF6346, MF6347, MF6348, MF6349), dated May 31, 2016 (ML16093A028)

In the Reference 1 letter, the U.S. Nuclear Regulatory Commission approved a proposed alternative to the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code,Section XI, "Rules for lnservice Inspection of Nuclear Power Plant Components," to use Code Case N-789 for Class 2 and 3 moderate-energy raw water piping system repairs resulting from degradation mechanisms such as erosion, corrosion, cavitation, or pitting. This relief request was approved for use at Calvert Cliffs Nuclear Power Plant, Units 1 and 2; Nine Mile Point Nuclear Station, Units 1 and 2; and A. E. Ginna Nuclear Power Plant, which were acquired by Exelon Generation Company, LLC (Exelon). This relief request was also previously approved for the Exelon fleet in the Reference 4 letter. Use of Code Case N-789-1 was previously approved for James A. FitzPatrick Nuclear Power Plant (JAFNPP) when owned by Entergy in the Reference 5 letter.

Since that time, Exelon has acquired the JAFNPP. Exelon is requesting approval of this relief for the JAFNPP for the next interval. Attached is a copy of the relief request as supplied in the Reference 2 letter to include the JAFNPP. Changes from the approved relief request (Reference 1) are identified by revision bars. Additionally, the Entergy request incorporated the use of Revision 1 to Code Case N-789. This relief incorporates Revision 1 of Code Case N-789 which has incorporated many of the changes contained in the Exelon relief request.

There are no regulatory commitments contained in this letter.

If you have any questions, please contact Tom Loomis (610) 765-5510.

Respectfully, James Barstow Director - Licensing and Regulatory Affairs Exelon Generation Company, LLC

Attachment:

Proposed Alternative to Utilize Code Case N-789-1 cc: Regional Administrator - NRC Region I NRC Senior Resident Inspector - James A. FitzPatrick Nuclear Power Plant NRC Project Manager - James A. FitzPatrick Nuclear Power Plant

Attachment Proposed Alternative to Utilize Code Case N-789-1

Attachment Proposed Alternative to Utilize Code Case N-789-1 Page 1 of 3

1. ASME Code Component(s) Affected:

All ASME Class 2 and 3 moderate energy carbon steel raw water piping systems. Raw water is defined as water such as from a river, lake, or well or brackish/salt water - used in plant equipment, area coolers, and heat exchangers. In many plants it is referred to as "Service Water." This Code Case applies to Class 2 and 3 moderate energy (i.e., less than or equal to 200°F (93°C) and less than or equal to 275 psig (1.9 MPa) maximum operating conditions) carbon steel raw water piping.

2. Applicable Code Edition and Addenda

PLANT INTERVAL EDITION START END James A. FitzPatrick Fifth 2007 Edition, through 2008 June 16, 2017 June 15, 2027 Nuclear Power Plant Addenda

3. Applicable Code Requirement

ASME Code,Section XI, IWA-4400 of the 2007 Edition, through 2008 Addenda provide the requirements tor welding, brazing, metal removal, and installation of repair/replacement activities.

4. Reason for Request

In accordance with 10 CFR 50.55a(z)(2), Exelon is requesting a proposed alternative from the I requirement tor replacement or internal weld repair of wall thinning conditions resulting from degradation in Class 2 and 3 moderate energy carbon steel raw water piping systems in accordance with IW A-4000. Such degradation may be the result of mechanisms such as erosion, corrosion, cavitation, and pitting - but excluded are conditions involving flow-accelerated corrosion (FAC), corrosion-assisted cracking, or any other form of cracking. IWA-4000 requires repair or replacement in accordance with the Owner's Requirements and the original or later Construction Code. Other alternative repair or evaluation methods are not always practicable because of wall thinness and/or moisture issues.

The primary reason for this request is to permit installation of a technically sound temporary repair to provide adequate time for evaluation, design, material procurement, planning and scheduling of appropriate permanent repair or replacement of the defective piping, considering the impact on system availability, maintenance rule applicability, and availability of replacement materials.

Performing code repair/replacement in lieu of implementing this Relief Request would in some cases necessitate extending Technical Specification actions to install a permanent repair/replacement, putting the plant at higher safety risks compared with the short time necessary to install a technically sound pad repair. Use of this Code Case may avoid a plant shutdown in situations where it may be necessary to shut the plant down for a code repair/replacement activity. This could result in an unnecessary plant transient and the loss of safety system availability as compared to maintaining the plant online.

Attachment Proposed Alternative to Utilize Code Case N-789-1 Page 2 of 3 Implementing this Relief Request during refueling outages will enable a greater number of scheduled corrosion inspections during the outages. The ability to install non-intrusive repair pads rather than scheduling contingency plans for piping replacement will enable longer corrosion inspection windows, increased scope of inspection, and improved overall plant safety.

5. Proposed Alternative and Basis for Use:

In accordance with 10 CFR 50.55a(z)(2), Exelon proposes to implement the requirements of ASME Code Case N-789-1 ("Alternative Requirements for Pad Reinforcement of Class 2 and 3 Moderate-Energy Carbon Steel Piping for Raw Water Service,Section XI, Division 1") as a temporary repair of degradation in Class 2 and 3 moderate energy raw water piping systems resulting from mechanisms such as erosion, corrosion, cavitation, or pitting, but excluding conditions involving flow-accelerated corrosion (FAC), corrosion-assisted cracking, or any other form of cracking. These types of defects are typically identified by small leaks in the piping system or by pre-emptive non-code required examinations performed to monitor the degradation mechanisms.

The alternative repair technique described in Code Case N-789-1 involves the application of a metal reinforcing pad welded to the exterior of the piping system, which reinforces the weakened area and restores pressure integrity. This repair technique will be utilized when it is determined that this temporary repair method is suitable for the particular defect or degradation being resolved.

The Code Case requires that the cause of the degradation be determined, and that the extent and rate of degradation in the piping be evaluated to ensure that there are no other unacceptable locations within the surrounding area that could affect the integrity of the repaired piping. The area of evaluation will be dependent on the degradation mechanism present. A baseline thickness examination will be performed for a completed structural pad, attachment welds, and surrounding area, followed by monthly thickness monitoring for the first three months, with subsequent frequency based on the results of this monitoring, but at a minimum of quarterly. Areas containing pressure pads shall be visually observed at least once per month to monitor for evidence of leakage. If the areas containing pressure pads are not accessible for direct observation, then monitoring will be accomplished by visual assessment of surrounding areas or ground surface areas above pressure pads on buried piping, or monitoring of leakage collection systems, if available.

For the pressure pad design, the higher of 2 times the actual measured corrosion rate or 4 times the estimated maximum corrosion rate for the system will be used. If the actual measured corrosion rate in the degraded location is unavailable, the estimated maximum corrosion rate for the system assumed in the design will be calculated based on the same degradation mechanism as the degraded location.

Paragraph 3.2(i) of the Code Case includes an incorrect reference to NC-2650 for the flexibility analysis associated with Class 2 designs. The correct reference should be NC-3650. Exelon will comply with NC-3650.

The repair will be considered to have a maximum service life of the time until the next refueling outage, when a permanent repair or replacement must be performed. Additional requirements for design of reinforcement pads, installation, examination, pressure testing, and inservice monitoring are provided in Code Case N-789-1.

Attachment Proposed Alternative to Utilize Code Case N-789-1 Page 3 of 3 Based on the above justification, the use of Code Case N-789-1 as a proposed alternative to the requirements of ASME Section XI will provide an acceptable level of quality and safety that does not impose an undue hardship.

All other ASME Section XI requirements for which relief was not specifically requested and authorized by the NRC staff will remain applicable including third party review by the Authorized Nuclear lnservice Inspector.

Code Case N-789-1 has not been incorporated into NRC Regulatory Guide 1.147, "lnservice Inspection Code Case Acceptability, ASME Section XI Division 1," and thus, is not available for application at nuclear power plants without specific NRC approval. Therefore, Exelon requests use of this alternative repair technique described in the Code Case via this relief request.

6. Duration of Proposed Alternative:

The proposed alternative is for use of the Code Case for the remainder of the ten (10) year inspection interval as specified in Section 2. When Code Case N-789-1 is approved for use by the NRC this relief request will no longer be applied and the Code Case, including Regulatory Guide 1.147 conditions, will be used in lieu of this relief request.

Any reinforcing pads installed before the end of the ten-year inservice inspection interval will be removed during the next refueling outage, even if that refueling outage occurs after the end of the ten-year interval.

7. Precedents:

1. Letter from J. Zimmerman (U.S. Nuclear Regulatory Commission) to M. Pacilio (Exelon Generation Company, LLC), Request to Use American Society of Mechanical Engineers Boiler and Pressure Vessel Code Case N-789, "Alternative Requirements for PAD Reinforcement of Class 2 and 3 Moderate-Energy Carbon Steel Piping for Raw Water Service,Section XI, Division 1," dated May 10, 2012(ML12121A637)

2. Letter from G. Miller (U.S. Nuclear Regulatory Commission) to B. Hanson (Exelon Generation Company, LLC), "Calvert Cliffs Nuclear Power Plant, Units 1 and 2; Nine Mile Point Nuclear Station, Units 1 and 2; and R. E. Ginna Nuclear Power Plant -

Proposed Alternative to Use Code Case N-789 (CAC Nos. MF7018 - MF77022)," dated May 19, 2016 (ML16138A021)

3. Letter from T. Tate (U.S. Nuclear Regulatory Commission) to J. Mccann (Entergy Services, Inc.), Relief Request RR-EN-15-1, Proposed Alternative to Use American Society of Mechanical Engineers Boiler and Pressure Vessel Code Case N-789-1, "Alternative Requirements for Pad Reinforcement of Class 2 and 3 Moderate Energy Carbon Steel Piping for Raw Water Service,Section XI, Division 1" (CAC Nos. MF6340, MF6341, MF6342, MF6343, MF6344, MF6345, MF6346, MF6347, MF6348, MF6349),

dated May 31, 2016 (ML16093A028)