RA-21-0262, Response to Request for Additional Information Regarding Proposed Alternative to ASME Boiler & Pressure Vessel Code Section XI Requirements for Repair/Replacement of Service Water (SW) System Buried Piping
| ML21277A306 | |
| Person / Time | |
|---|---|
| Site: | Brunswick  |
| Issue date: | 10/04/2021 |
| From: | Krakuszeski J Duke Energy Progress |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML21277A305 | List: |
| References | |
| RA-21-0262 | |
| Download: ML21277A306 (28) | |
Text
John A. Krakuszeski Vice President Brunswick Nuclear Plant 8470 River Rd SE Southport, NC 28461 o: 910.832.3698 Contains Proprietary Information Withhold in Accordance with 10 CFR 2.390 October 4, 2021 Serial: RA-21-0262 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Brunswick Steam Electric Plant, Unit Nos. 1 and 2 Renewed Facility Operating License Nos. DPR-71 and DPR-62 Docket Nos. 50-325 and 50-324
Subject:
Response to Request for Additional Information Regarding Proposed Alternative to ASME Boiler & Pressure Vessel Code Section XI Requirements for Repair/Replacement of Service Water (SW) System Buried Piping in Accordance with 10 CFR 50.55a(z)(1)
References:
- 1. Letter from John A. Krakuszeski (Duke Energy) to the U.S. Nuclear Regulatory Commission Document Control Desk, "Proposed Alternative to ASME Boiler & Pressure Vessel Code Section XI Requirements for Repair/Replacement of Service Water (SW)
System Buried Piping in Accordance with 10 CFR 50.55a(z)(1)," dated February 24, 2021, ADAMS Accession Number ML21055A797.
- 2. Letter from John A. Krakuszeski (Duke Energy) to the U.S. Nuclear Regulatory Commission Document Control Desk, "Additional Information Regarding Proposed Alternative to ASME Boiler & Pressure Vessel Code Section XI Requirements for Repair/Replacement of Service Water (SW) System Buried Piping in Accordance with 10 CFR 50.55a(z)(1)," dated May 3, 2021, ADAMS Accession Number ML21123A293.
- 3. Letter from John A. Krakuszeski (Duke Energy) to the U.S. Nuclear Regulatory Commission Document Control Desk, "Additional Information Regarding Proposed Alternative to ASME Boiler & Pressure Vessel Code Section XI Requirements for Repair/Replacement of Service Water (SW) System Buried Piping in Accordance with 10 CFR 50.55a(z)(1)," dated June 22, 2021, ADAMS Accession Number ML21173A253.
- 4. Letter from Zackary R. Stone (US NRC) to John A. Krakuszeski (Duke Energy),
"Request for Additional Information Regarding Proposed Alternative to ASME Boiler &
Pressure Vessel Code Section XI Requirements for Repair/Replacement of Service Water (SW) System Buried Piping," dated September 8, 2021, ADAMS Accession Number ML21239A065.
Ladies and Gentlemen:
On February 24, 2021, as supplemented by letters dated May 3, 2021, and June 22, 2021 (i.e.,
References 1, 2, and 3), Duke Energy Progress, LLC (Duke Energy) requested approval to allow the use of the V-Wrap' Carbon Fiber Reinforced Polymer (CFRP) Composite System for the internal repair of the buried Service Water (SW) System piping at Brunswick Steam Electric
U.S. Nuclear Regulatory Commission Page 2 of 2 Plant (BSEP). On September 8, 2021 (i.e., Reference 4), the NRC provided a request for additional information (RAI) regarding the proposed alternative. This submittal provides Duke Energy's response to the RAI. Additionally, the response corrects a typographical error that was identified in Reference 1. contains information that Structural Group, Inc. and Simpson Gumpertz & Heger, Inc. consider to be proprietary. Proprietary information withheld under 10 CFR 2.390 is identified by text enclosed within double brackets. Affidavits supporting this request are provided in. A non-proprietary (i.e., redacted) version of the response is provided in.
This document contains no new regulatory commitments. Please refer any questions regarding this submittal to Mr. Lee Grzeck, Acting Director - Nuclear Fleet Licensing, at (980) 373-1530.
Sincerely, John A. Krakuszeski MAT/mat
Enclosures:
cc:
- 1. Response to Request for Additional Information Proposed Alternative to ASME Section XI Requirements for Repair/Replacement of Buried Service Water Piping
[Proprietary Information - Withhold from Public Disclosure in Accordance with 10 CFR 2.390]
- 2. Affidavits for Withholding Proprietary Information from Public Disclosure
- 3. Response to Request for Additional Information Proposed Alternative to ASME Section XI Requirements for Repair/Replacement of Buried Service Water Piping (Redacted)
Ms. Laura Dudes, NRC Regional Administrator, Region II Mr. Andrew Hon, NRC Project Manager Mr. Zackary Stone, NRC Project Manager Mr. Gale Smith, NRC Senior Resident Inspector Chair - North Carolina Utilities Commission
RA-21-0262 Affidavits for Withholding Proprietary Information from Public Disclosure
U. S. Nuclear Regulatory Commission Document Control Desk 11555 Rockville Pike Rockville, MD 20852 RE: Application for Withholding Proprietary Information from Public Disclosure Ladies and Gentlemen:
Structural Group, Inc. (SGI), has provided certain proprietary information to Brunswick Electric Steam Plant (BSEP) Unit Nos. 1 and 2 in connection with a request by Duke Energy Progress, LLC from the U. S. Nuclear Regulatory Commission (USNRC) to respond to Reference 5. This application requests that proprietary information of SGI be protected from public disclosure. The proprietary information prepared in support of Reference 5 for which withholding is being requested is further identified in the attached affidavit signed by the owner of the proprietary information, SGI, on behalf of itself and any wholly-owned subsidiaries or affiliated companies.
An affidavit accompanies this letter, setting forth the basis on which the information may be withheld from public disclosure by the USNRC and addressing with specificity the considerations listed in paragraph (b)(4) of 10 CFR 2.390 (Reference 6) of the USNRC regulations.
A request for withholding proprietary information has been previously approved by the USNRC at the Surry Nuclear Station (Reference 1), South Texas Project (Reference 2), Arkansas Nuclear One (Reference 3) and Brunswick Electric Steam Plant (Reference 4). Accordingly, this letter authorizes the utilization of the accompanying Affidavit by Duke Energy Progress, LLC. Correspondence with respect to the proprietary aspects of the Application or the Affidavit should reference this letter and be addressed to Scott Greenhaus, Executive Vice President, Structural Group, Inc., 10150 Old Columbia Road, Columbia, MD 21046.
Very truly yours, Scott Greenhaus, Executive Vice President
REFERENCES:
- 1.
USNRC letter to Virginia Electric & Power Company, Surry Power Station, Unit Nos. 1 and 2 - Relief from the Requirements of the ASME Code (CAC Nos. MF8987 and MF8988; EPID L-2016-LLR-0019), (ML17303A068), dated December 20, 2017.
- 2.
USNRC letter to South Texas Project Nuclear Operating Company, South Texas Project Units 1 and 2 - Proposed Alternative RR-ENG-3-24 to ASME Boiler & Pressure Code Requirements for Repair of Essential Cooling Water (ECW) System Class 3 Buried Piping, (EPID-L-2019-LLR-0096), dated September 3, 2020.
- 3.
Letter from USNRC to Entergy Operations, Inc., Arkansas Nuclear One, ANO Site Vice President, "Arkansas Nuclear One, Units 1 and 2 - Request for Withholding Information from Public Disclosure (EPID L-2020-LLR-0104), (ML20293A184).
- 4.
USNRC Letter to Brunswick Steam Electric Plant, Brunswick Steam Electric Plant, Units 1 and 2 - Request for Withholding Information from Public Disclosure (EPID L-2021-LLR-0014), dated July 16, 2021 (ML21181A384).
- 5.
Letter from Zackary R. Stone (US NRC) to the John A. Krakuszeski (Duke Energy),
"Request for Additional Information Regarding Proposed Alternative to ASME Boiler &
Pressure Vessel Code Section XI Requirements for Repair/Replacement of Service Water (SW) System Buried Piping," dated September 8, 2021, ADAMS Accession Number ML21239A065.
- 6.
10 CFR 2.390, "Public Inspections, Exemptions, Requests for Withholding."
RA-21-0262 Page 1 of 19 Response to Request for Additional Information Proposed Alternative to ASME Section XI Requirements for Repair/Replacement of Buried Service Water Piping
Background
On February 24, 2021, as supplemented by letters dated May 3, 2021, and June 22, 2021, Duke Energy Progress, LLC (Duke Energy) requested approval to allow the use of the V-Wrap' Carbon Fiber Reinforced Polymer (CFRP) Composite System for the internal repair of the buried Service Water (SW) System piping at Brunswick Steam Electric Plant (BSEP). On September 8, 2021, the NRC provided a request for additional information (RAI) regarding the proposed alternative. The responses to this RAI follow.
EMIB RAI-1:
The scope section of Attachment A in Enclosure 2 of the submittal mentions that it has not been determined whether the cement mortar lining will be removed or remain in place for upgrade of Brunswick service water piping using CFRP composite lining. Attachment B, Table 1 of provides a minimum average requirement for shear bond strength between CFRP and steel of ((
)). Section 5A.3.1 of Attachment A in Enclosure 5 lists shear bond strength of CFRP on host pipe of ((
)), which is also used in calculations in Attachment C of Enclosure 5.
(a) Discuss the applicability of the above noted shear bond strength values for the following situations:
- a. Between CFRP and host steel pipe when the cement lining is removed, and
- b. Between CFRP and host steel pipe when cement lining remains in place.
Response
((
))
(b) Discuss the acceptability of shear bond strength of ((
)).
Response
((
))
RA-21-0262 Page 2 of 19 EMIB RAI-2:
Figures S-7 and S-8 in Attachment D to Enclosure 5 of the submittal provide illustrations of CFRP composite system termination detail at straight ends, and repair terminations, where a certain length of host pipe is required to act compositely with the CFRP system. At the ends of the repair, a good bond with host pipe substrate is critical to maintain structural integrity so that the CFRP composite system can transfer loads to the host pipe. Provide additional discussion to address the following related to the intact or non-repaired side of the terminations.
(a) Whether the intact piping on the non-repaired side of terminations is buried, or whether all non-repaired side is above ground.
Response
The majority of the termination points where the host pipe is relied upon for load transfer will be located approximately 1-2 feet within the Service Water, Reactor or Radwaste Buildings with the exception of the following:
- a. Unit 1 Conventional Service Water Header within line 1-SW-100-24-157. This piping is scheduled to be replaced in its entirety during the subsequent 2026 Refueling Outage, at which point this termination point will be located within new piping equipped with a new protective exterior coating (or enhanced material such as AL6XN).
- b. Unit 2 Nuclear Service Water Header tap off to the Emergency Diesel Generator Jacket Water Coolers. This tap off is a 2 foot, 7.5 inches section of 18 inch diameter carbon steel piping that connects to the 18 inch copper nickel jacket water cooler supply line. This piping will be examined prior to CFRP installation to ensure it meets the minimum wall thickness requirements and any necessary repairs will be made.
- c. The new manway locations being installed on each header (total of 8), for access during CFRP installation, will each have a termination point that attaches to AL6XN material. These manways will be buried following installation. These accesses will have a protective coating applied to the exterior of the piping.
(b) The distance from the termination end to the end of buried portion of pipe or to the beginning of aboveground piping in the building penetrations or valve pits.
Response
The termination ends that are installed at above ground piping locations (Service Water Building, Reactor Building and Radwaste Building) will be located as close to the building penetrations as possible. The termination ends of the CFRP composite system will extend approximately 1-2 feet into each building.
(c) The distance from termination end to the piping supports or anchors in the vicinity for the aboveground piping.
RA-21-0262 Page 3 of 19
Response
As stated above, the termination ends within each building will be located within 1-2 feet of the wall penetrations. Given this information, the nearest piping support will be the associated wall penetrations and the additional weight from these 1-2 foot long termination points is considered negligible.
(d) Repair terminations interface with the repaired and the non-repaired sides of the piping. It appears that the loads from the repaired side are considered. Provide a discussion on structural integrity of the repair terminations from consideration of any dead weight, thermal, seismic, and any other applicable loadings from the non-repaired side for the terminations at Reactor Building wall, radwaste tunnel, and service water pumphouse. Address the structural integrity of the terminations for combined loads from repaired side and non-repaired or above ground continuation piping.
Response
((
RA-21-0262 Page 4 of 19
))
(e) Attachment C of Enclosure 5 lists a stress of ((
)) of maximum longitudinal demand from non-repair side. Discuss if this stress represents the effect from all loadings from nonrepaired side combined with the effects from loads from repaired side to verify the structural integrity of the termination interfaces.
Response
See response to RAI EMIB-2(d).
EMIB RAI-3:
Attachment F in Enclosure 5 discusses seismic analysis for the design basis earthquake (DBE) combined with emergency operating conditions for service water piping. The seismic analysis of the piping is performed using the analytical software ABAQUS. Attachment F to Enclosure 5 states that seismic ground strain analysis is based on 100-40-40 combination rule described in American Society of Civil Engineers, ASCE/SEI 4-16, Seismic Analysis of Safety-Related Nuclear Structures. Discuss how this seismic analysis compares with the original design criteria. 100-40-40 combination refers to three orthogonal directions. Eight load cases were considered but included only two horizontal directions. The third orthogonal direction (vertical) appears to be not considered. Please provide rationale to justify the approach used.
Response
((
))
EMIB RAI-4:
Some recent limited testing data indicates that the glass transition temperature (Tg) is also dependent on the cure temperature. If the actual cure temperature in the field is not high enough, the glass transition temperature, as listed in Enclosure 4, Attachment B, Table 3, of Tg max ((
)) may not be achieved. When Tg is very close to Tmax with no
((
)), the epoxy may become rubbery and the CFRP system may lose its structural integrity and therefore capability to support the applied loads.
RA-21-0262 Page 5 of 19 (a) Provide discussion and any test data on field cure temperature effect, and realistic glass transition temperature achievable with curing temperatures attainable during actual CFRP repair field installation conditions at Brunswick.
Response
For the purposes of this response the following definitions are provided:
((
))
Tmax is defined as the system maximum design water temperature of 105 °F with a typical operating temperature range of 40 °F to 90 °F.
The acceptance criteria for ((
)) are described below.
((
)) is a material property used to evaluate if the epoxy is suitable for the Brunswick application by ((
))
((
))
V-Wrap' 770 epoxy ((
)) the maximum achievable system temperature of 105 °F ( = Tmax) ((
)).
((
))
As discussed below and shown on Figures 2, 3, and 4 included herein a ((
))
margin above Tmax ( = 105 °F) will keep V-Wrap' 770 epoxy ((
))
General Design Criteria - Material Properties
((
)) is a general design criterion for the initial selection of an epoxy material for use at Brunswick. ((
)) for an epoxy and ((
)). Using ((
)) for V-Wrap' 770 epoxy is ((
)) °F. Based on
((
)) for Brunswick:
((
))
RA-21-0262 Page 6 of 19 Material Behavior Figure 1 below shows the theoretical behavior of an amorphous thermoplastic epoxy based on an ASTM E1640, Dynamic Mechanical Analysis (DMA) testing protocol. At lower temperatures, the epoxy remains in a glassy state. At the glass transition temperature, the epoxy becomes leathery and at a higher temperature it behaves like a soft elastic rubber.
Figure 1 (Reference 1)
V-Wrap' 770 ((
))
Figures 2, 3 and 4 below provide ((
)) test results for V-Wrap' 770 epoxy ((
)).
Results from these ((
)) laboratory tests demonstrate that V-Wrap' 770 epoxy ((
)) for the maximum achievable system temperature of 105 °F ( = Tmax) at Brunswick. These test temperatures ((
)) bound the design basis, normal operating, and maximum achievable
RA-21-0262 Page 7 of 19 temperatures for this system at Brunswick, which has a typical operating temperature range of 40 °F to 90 °F. The installed CFRP composite system will be cured as determined by Brunswick specific ((
)). The design temperature used for the Brunswick CFRP composite system is 105 °F. The ((
)). This approach ensures V-Wrap' 770 epoxy ((
)) at Brunswick using the criterion ((
))
Figure 2 - V-Wrap' 770 epoxy ((
))
((
))
RA-21-0262 Page 8 of 19 Figure 3 - V-Wrap' 770 epoxy ((
))
((
))
RA-21-0262 Page 9 of 19 Figure 4 - V-Wrap' 770 epoxy ((
))
((
))
Glass Transition Temperature Summary
((
)) are acceptable for Brunswick.
((
)) for V-Wrap' 770 epoxy ((
)) in the initial design process ((
)):
((
))
As demonstrated by ((
)) V-Wrap' 770 epoxy cured at a ((
)) and will not behave ((
)) at the maximum achievable system temperature of 105°F ( = Tmax) and satisfies the acceptance criterion:
((
))
(b) Include a detailed discussion to provide assurance that the epoxy will not become rubbery, and the CFRP system will be capable of supporting the applied loading at the maximum operating temperature of ((
)). Provide a discussion on how much will be the margin between realistic Tg achievable for curing and installation at Brunswick and maximum operating temperature of ((
)).
RA-21-0262 Page 10 of 19
Response
((
))
(c) It appears that Enclosure 6 Attachment C and Enclosure 7 address tension testing and degree of cure testing of witness panels. However, the submittal does not discuss testing for glass transition temperature of the as-installed field cured CFRP repair. The licensee is requested to address testing of witness panels representing the as installed field cured conditions for Tg to demonstrate that Tg Tmax + margin.
Response
((
))
(d) The following cautionary note is provided in Section 401-VIII-4 CURE of ASME PCC 2018 standard.
Caution: Each polymer in the repair system can be cured to a range of glass transition temperatures. Repair systems will not achieve the ultimate glass transition temperature determined by the qualification testing specified in this Standard unless they experience the same temperature for the same period of time as the sample tested. Repairs designed for elevated temperature service will not meet the requirements of this Article unless they are subject to a post-cure (heating) cycle that matches the thermal history of the sample tested during qualification.
Please provide a discussion on whether the Brunswick CFRP piping repair installation will satisfy the above cautionary note.
Response
The CFRP Composite System proposed to be used at Brunswick ((
)) Material properties are initially determined to support the ((
)) and are included in Enclosure 4, Attachment B, "Material Qualification and Testing", Tables 1, 2, and 3. These test results represent the ((
)). These tests are performed at ((
)), unless otherwise noted in ((
)), or at other conditions as specified in the relevant standards.
RA-21-0262 Page 11 of 19 As presented in Figure 5, below the ((
)) requires these ((
)) of ((
)) and ((
)) to be controlled as ((
)).
Figure 5 ((
))
((
))
((
)) for ((
)) are ((
)) as the V-Wrap' CFRP composite system installed in the pipeline. ((
)) have demonstrated that ((
RA-21-0262 Page 12 of 19
)) and the maximum achievable temperature (Tmax = 105 °F) for Brunswick.
EMIB RAI-5:
Attachment A to Enclosure 9 discusses operating experience and provides a list of successful applications of CFRP composite systems in piping.
(a) Clarify if any of those listed in Enclosure 9 include similar cure at elevated temperatures, and whether the epoxy used is the same as that planned for use at Brunswick.
Response
As necessary to meet ((
))
All examples listed in Enclosure 9 ((
)) for the CFRP Composite System at Brunswick.
(b) Also, clarify if any of those in Enclosure 9 include CFRP repair of steel piping with cement mortar lining.
Response
((
))
EMIB RAI-6:
Attachment C to Enclosure 5 summarizes that the CFRP system design for Brunswick consists of the ((
RA-21-0262 Page 13 of 19
)).
Response to Parts (a) and (b):
((
))
We have tensile test results for samples exposed to water and salt water for more than 10,000 hour0 days <br />0 hours <br />0 weeks <br />0 months <br /> immersion at 150 °F which is higher than the typical operating range of 40 °F to 90 °F and the maximum achievable water temperature of Tmax = 105 °F at Brunswick. These tests were performed as a part of our test program to study the effects of the cure temperature on material properties at elevated surface temperature presented to NRC. After exposure, samples were tested per ASTM D3039 at 73 °F and 140 °F demonstrating that the V-Wrap' CFRP composite system will not transition from the glassy state to a leather or rubbery state after long term exposure to water at elevated temperature, higher than the maximum achievable water temperature. The samples after long term exposure had equal or higher properties than samples exposed to an elevated temperature for a short time, indicating that the adjustment assumed in design for cure temperature and exposure temperature is conservative.
The material adjustment factors provided in Table 4 on Page 35 of 122 in Enclosure 5 Attachment A are based on the long term water exposure of CFRP at temperatures which bound the normal operating and maximum achievable water temperature at Brunswick. These factors have been utilized in the design for the maximum achievable water temperature of 105 °F. In addition, the tensile strength for the field cured samples will be tested at Tmax and the design strength will be accordingly adjusted if necessary, as discussed above in response to EMIB RAI-4.
EMIB-RAI 7:
In Enclosure 5 it is mentioned that the minimum expected ((
)).
RA-21-0262 Page 14 of 19 It is noted from Enclosure 4 Section 2.1 of the submittal that ((
)) are used in water tightness testing. During the curing process of CFRP repair installation, please confirm that ((
))
(a) The licensee is requested to clarify if the 90 °F cure temperature is at the farthest point of the pipe from the heaters because the temperature drops at the farthest location from the heaters. In addition, clarify the cure durations that will be used during CFRP installation in the field corresponding to the cure temperatures of 90 °F and 105 °F.
Response
The ((
)). The installed CFRP composite system ((
)) At the ((
)), the installed CFRP composite system ((
)) The cure duration used in the field will be sufficiently long to achieve the required minimum 85% degree of cure which will be verified ((
))
(b) The licensee is also requested to clarify whether the witness panels during installation of the CFRP repair are collected from various locations including at terminations (hottest locations) and farthest locations from the terminations.
Response
((
)). Witness panels will ((
)) The witness panels ((
))
(c) The glass transition temperature and mechanical properties (tensile strength, modulus, flexural strength, shear strength) at the maximum operating temperature to which the CFRP repair is exposed, are affected by the cure temperature. Therefore, the licensee is further requested to clarify that the witness panels, representative of the curing during actual installation of CFRP, will be tested not only for mechanical properties and degree of cure but also for the glass transition temperature.
Response
((
))
RA-21-0262 Page 15 of 19 (d) Discuss whether the effect of cure temperature variation from terminal ends to farthest points during installation is given consideration on the structural integrity of CFRP installation.
Response
((
)) See response to EMIB-RAI 7(b) above for additional information.
EMIB RAI-8:
Attachment C in Enclosure 5 of the submittal provides a summary table of computed ((
)) and for 3 separate soil covers of 12.25 ft, 19.5 ft, and 6.75 ft. The table also provides factor of safety limits for the 9 limit states. Unlike metallic materials, there are many unknown uncertainties associated with CFRP composite materials which are non-isotropic, and the analytical methods. Further, CFRP materials have significant variation in material properties. A-Basis properties are more appropriate for use in safety related ASME Section III design. A review of the table indicates that ((
)). Discuss design improvements or modifications required to satisfy the required factor of safety.
Response
((
RA-21-0262 Page 16 of 19
))
NPHP RAI-1:, Attachment B, Table 2 discusses the ((
)) Enclosure 5, Attachment B provided the ((
))
Clarify whether the ((
))
Response
((
))
NPHP RAI-2:, Attachment A, Section 17, page 15 of 36 stated, in part, that:
((
))
Discuss how the CFRP composite system that ((
))
Response
Depending on the results of the NFPA 805 assessment, the piping that terminates inside the Reactor Building, Pipe Tunnel or SW Pump House may be coated with ((
RA-21-0262 Page 17 of 19
)) the CFRP Composite System. This assessment will verify that the CFRP Composite ((
))
NPHP RAI-3:, Attachment B, page 16 of 17 stated, in part, that:
((
))
Clarify whether the ((
))
Response
The Watertightness Report provided in Enclosure 4, Attachment C ((
))
NPHP RAI-4:, Attachment A, page 3 of 11 stated, in part, that:
It has not been determined whether the cement mortar lining will be removed or remain in place. Hydraulic and structural analysis will be performed to justify either condition, (1) cement mortar lining removed or (2) cement mortar lining remains.
Furthermore, Enclosure 5, Attachment D, page 83 of 122 stated, in part, that:
((
))
(a) For terminal ends, clarify whether the CFRP will be installed on host pipes bare metal or on the concrete mortar lining. If the answer is on the concrete mortar lining, provide justification.
Response
At the terminal ends ((
))
RA-21-0262 Page 18 of 19 (b) ((
))
Response
Any through hole defect within the terminal end (irrespective of size) that does not meet minimum wall thickness requirements will require a welded repair. The ((
))
(c) ((
))
Response
((
))
(d) Clarify whether the pipe metallic substrate is cathodically protected to minimize the corrosion and loss of metal from outside of the pipe.
Response
The buried piping is cathodically protected.
(e) RA-20-0353 referenced ASME Code Case N-871, Repair of Class 2 & 3 Piping Using Carbon Fiber Reinforced Polymer Composites, that was approved by the ASME Code.
Clarify why the CFRP composite system and the terminal ends of metallic substrate will not be inspected (e.g., visually, acoustically, or both) following installation at the second period of the current 10-year ISI interval to monitor the soundness of the installed CFRP composite system.
Response
The V-WrapTM CFRP Composite System piping is proposed for the remaining life of the plant and any repair/replacement and/or inspection of the CFRP Composite
RA-21-0262 Page 19 of 19 System will be conducted in accordance with the applicable edition of ASME Boiler &
Pressure Vessel Code,Section XI or approved alternative thereafter, at the time of the repair/replacement or inspection. ASME B&PVC Code Case N-871 / N-871-1, Repair of Class 2 & 3 Piping Using Carbon Fiber Reinforced Polymer Composites, will not apply to inservice inspection of the modified CFRP Composite System piping and the terminal ends of metallic substrate.
Identification of Typographical Error Subsequent to submittal, a typographical error was identified in the February 24, 2021 request to allow the use of the V-Wrap' CFRP Composite System for the internal repair of the buried SW System piping at BSEP. The error is in Equation 58 on Page 33 of 122 of Enclosure 5 of the submittal. The corrected Equation 58 is:
FS.(for buckling)
.buck buck seismic.comp Reference
- 1. ((
))