TXX-0620, Update to 60-Day Response to Revision 1 of NRC Order EA-03-009, Issuance of First Revised NRC Order (EA-03-009) Establishing Interim Inspection Requirements for Reactor Pressure Vessel Heads at Pwrs

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Update to 60-Day Response to Revision 1 of NRC Order EA-03-009, Issuance of First Revised NRC Order (EA-03-009) Establishing Interim Inspection Requirements for Reactor Pressure Vessel Heads at Pwrs
ML063630152
Person / Time
Site: Comanche Peak  Luminant icon.png
Issue date: 12/18/2006
From: Madden F
TXU Generation Co, LP, TXU Power
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
EA-03-009, TXX-06204
Download: ML063630152 (28)
v • d • e


Text

{{#Wiki_filter:Txu Power fl(U Power Comanche Peak Steam Electric Station P.O0. Boxl1002 (EOi) Glen Rose, TX 76043 Tel: 254 897 5209 Fax: 254 897 6652 mike.blevins@txu.com Mike Blevins Senior Vice President & Chief Nuclear Officer Ref. IOCFR5O.54(f) CPSES-20060248 1 Log # TXX-06204 December 18, 2006 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555

SUBJECT:

REF: COMANCHE PEAK STEAM ELECTRIC STATION (CPS ES) DOCKET NOS. 50-445 AND 50-446 UPDATE TO 60-DAY RESPONSE TO REVISION I OF NRC ORDER EA-03-009, "ISSUANCE OF FIRST REVISED NRC ORDER (EA-03-009) ESTABLISHING INTERIM INSPECTION REQUIREMENTS FOR REACTOR PRESSURE VESSEL HEADS AT PRESSURIZED WATER REACTORS" I. TXU Power letter logged TXX-05 121, dated June 27, 2005 from Mike Blevins to the NRC

2. TXU Power letter logged TXX-0609-3, dated June 22, 2006 from Mike Blevins to the NRC

Dear Sir or Madamn:

On February.1 1, 2003, the NRC issued Order EA-03 -009 for interim inspection requirements for reactor pressure vessel (RPV) heads at pressurized water reactor (PWR) facilities. On February 20, 2004, the NRC issued the First Revised Order.EA-03-009 (the Order), which superseded Order EA-03-009. Revision 1 of the Order modified the requirements regarding nondestructive examination of the penetration nozzles. A member of the STARS (Strategic Teaming and Resource Sharing) Alliance Callaway - Comanche Peak

  • Diablo Canyon o Palo Verde o South Texas Project
  • Wolf Creek AMl

TXX-06204 Page 2 of 4 The RPV head for CPSES Unit 2 meets the criteria for the "Low" susceptibility category in Section IV.B. The Order requires that RPV heads in this category complete a baseline volumetric examination in accordance with the Order before February 11, 2008. Pursuant to this requirement, TX-U Power undertook a compliant examination during the Unit 2 eighth refueling outage (Spring 2005). In planning this inspection, two peripheral penetrations employed for the reactor vessel level instrumentation system (RVLLS) were identified as having unique guide sleeves installed that would require modification in order to inspect the penetration tube. Although the necessary modifications were planned and implementation was attempted, unanticipated obstructions in both guide sleeves prevented implementation. Consequently, 76 of 78 control rod drive mechanism (CRDM) penetrations and the one-inch diameter head vent were successfully examined with no relevant indications but the two RVLIS penetrations were not examined. In addition, CPSES Unit 2 completed the 100% bare metal visual examinations (BMV) required by the Order during the Unit 2 seventh refueling outage (Fall 2003). As a contingency, TXU Power requested relaxation from the implementation deadline specified in Section IV(C)(3) for the Section IV, Paragraph C.(5)(b) volumetric examination requirement of the CPSES Unit 2 RPV head for the two penetration nozzles not yet examined per Reference 2. However, plans and necessary tooling were developed and the required examinations were completed within the deadline established in the Order during the Fall 2006 refueling outage (2RF09). Attachment 1 to this letter provides the information required by the Order for these two penetrations to update the response provided in Reference I. Furthermore, TXU Power requests that the relaxation requested in Reference 2 be withdrawn as it is no longer necessary for CPSES Unit 2. As identified in Reference I, TXU` Power has determined that because of the physical configuration of certain CPSES Unit 2 RPV nozzles, the required coverage specified in Section IV.C.(5)(b)(i) of the Order could not be met for these nozzles and therefore, in accordance with Section IV.F.(2) of the Order, relaxation is requested because compliance with the Order would result in a hardship or unusual difficulty without a compensating increase in the level of quality and safety. Specifically, for five RPV penetration nozzles, TXU Power is requesting relaxation from the Order by proposing to redefine the Section IV.C.(5)(b)(i) inspection area as "the volume of the penetration tube extending from two inches above the i-groove weld down to the lowest elevation that can be practically inspected." The details of the Relaxation Request are contained in Attachment 2.

TXX-06204 Page 3 of 4 The technical justification for the relaxation request is provided in Enclosure 1, WCAP-16397-P, Revision 0, "Structural Integrity Evaluation of Reactor Vessel Upper Head Penetrations to Support Continued Operation: CPSES Units I and 2." A non-proprietary version of WCAP-1 6397-NP, Revision 0 is provided in Enclosure 2. Westinghouse has determined that information contained in Enclosure 1 is proprietary, and is thereby supported by an affidavit signed by Westinghouse, the owner of the information. The aftidavit sets forth the basis on which the information may be withheld from public disclosure by the Commission and addresses with specificity the considerations listed in paragraph (b)(4) of 1 OCFR 2.3190. Accordingly, it is respectfully requested that the information that is proprietary to Westinghouse be withheld from public disclosure in accordance with 10CFR 2.390, "Public inspections, exemptions, requests for withholding," of the Commission's regulations. contains Westinghouse authorization letter CAW-05-2032, its accompanying affidavit, Proprietary Information Notice, and Copyright Notice. Correspondence with respect to the copyright or proprietary aspects of the items listed above or the supporting Westinghouse affidavit, should reference CAW-05-2032 and should be addressed to J. A. Gresham, Manager, Regulatory Compliance and Plant Licensing, Westinghouse Electric Company LLC, P.O. Box 355, Pittsburgh,. Pennsylvania 15230-0355. The attached relaxation request is specific to CPSES Unit 2. The CPSES Unit 1 RPV head is scheduled for replacement in the Spring refueling outage of 2007.

TXX-06204 Page 4 of 4 This communication contains no new licensing basis commitments regarding CPSES Units 1 and 2. Should you have any questions, please contact Mr. J. D. Seawright at (254) 897-0140. 1 state under penalty of perjury that the foregoing is true and correct. Executed on December 18, 2006. Sincerely, TXU Generation Company LP By: TXU Generation Management Company LLC Its General Partner Mike Blevins By: 412K/YLL- '~red W. Madden Director, Oversight and Regulatory Affairs JDS Attachments: 1. Update to 60-Day Order Response

2. Relaxation Request
3. Application for Withholding (CA W-05 -2032)

Enclosures

1. WCAP-16397-P (Proprietary)
2. WCAP-16397-NP (Non-Proprietary) c -

B. S. Mallett, Region IV (CLO and Attachments only) M. C. Thadani, NRR (CLO, Attachments and two Enclosures each) Resident Inspectors, CPSES (CLO and Attachments only) to TXX-06204 Page 1 of 2 Updated 60-Day Response to NRC Order EA-03-009, "Issuance of First Revised NRC Order (EA-03-009) Establishing Interim Inspection Requirements for Reactor Pressure Vessel Hleads at Pressurized Water Reactors" NRC Required Information: The first revision of NRC Order EA-03-009, dated February 20, 2004, required that, for each inspection required in Paragraph C of the Order, the Licensee shall submit a report detailing the inspection results within 60 days after returning the plant to operation. For each inspection required in Paragraph D of the Order, the Licensee shall submit a report detailing the inspection results within 60 days after returning the plant to operation if a leak or boron deposit was found during the inspection. TXU Power Response: CPSES Unit 2 accumulated approximately 1.99 total effective degradation years prior to 2RF08. Therefore, TXU Power is required to comply with Sections IV.C.(3) and IV.D of the First Revised Order EA-03-009 (the Order). Section lV.C (3) requires a bare metal visual exam at least every third refueling outage or five years and a nonvisual NDE prior to February 11, 2008 TXU Power previously complied with Section IV.C.(3)(a) of the Order by performing a bare metal visual inspection of 100 percent of the reactor pressure vessel (RPV) head penetrations, including 360 degrees around each of the vessel head penetration (VHP) nozzles and the head vent penetration, during 2RF07, completed in the fall of 2003 (Reference 2). The next bare metal exam must therefore be completed no later than fall of 2008 per the Order. However, TXU Power perform-ed a general visual assessment of the RPV head surface under the insulation during 2RF08 (spring 2005) and 2RF09 (Fall 2006) to identify anything unusual indicative of conditions that would wairant further investigation. No evidence of VHP nozzle leakage or cracking, or degradation of the RPV head was identified. TXU Power partially complied with Section IV.C.(3)(b) of the Order by performing non-visual NDE volumetric examination of 77 of 79 reactor head penetration tubes (RHPT), including the head vent penetration. A combination of ultrasonic and eddy current testing methods were used with probes delivered to the tubes by a remote positioning device (or manually in the case of the head vent tube). The inspection encountered limitations to the Order's specified examination areas in five of the RHPTs due to the large as-built configuration of the i-welds, the threads at the end of these specific tubes, and the geometry of the transducers on the examination probes. The examination details and technical justification for acceptability are attached in a request for relaxation per section IV.F of the Order.

Attachment I to TXX-06204 Page 2 of 2 The two remaining RHPTs house probes for the reactor vessel level indicating system which have a permanently installed guide sleeve that precludes access to the penetration tube ID surface for inspection. This obstructed condition was identified while planning the examination and a design modification was developed to clear the obstruction and allow access for inspection. However, unexpected conditions were encountered that interfered with the tooling and efforts to implement the modification were halted in 2RF08. These two remaining locations were successfully inspected in 2RF09 using both ultrasonic testing and eddy current. The examinations detected no discontinuities or indications of boric acid leak paths; no flaws needing disposition or corrective action were identified. TXU Power complied with Section D of the Order by performing a visual inspection to identify potential boric acid leaks from pressure-retaining components above the RPV head. No evidence of leakage was identified. to TXX-06204 Page 1 of 13 Relaxation Request for Inspection Coverage from First Revised Order EA-03-009 CPSES Unit 2 Component Comanche Peak Unit 2 has seventy-nine (79) reactor pressure vessel (RPV) head penetration nozzles comprised of fifty-seven (57) penetration tubes with thermnal sleeves, two locations with reactor vessel level instrumentation system (RVLIS) belimouth guide funnel assemblies, nineteen (19) locations without thermal sleeves, and one (1) vent penetration nozzle. In accordance with Section IV.A of the First Revised NRC Order EA-03-009 (hereafter referred to as the Order), the Comanche Peak Unit 2 susceptibility category is classified as "low" based on a calculated value of less than eight effective degradation years (EDY) and no previous inspection findings prior to the Spring 2005 refueling outage (2RF08). Results of this examination were previously submitted by letter TXX-05121 dated June 27, 2005 (ADAMS Accession No. ML051870337). NRC Order EA-03-009 Applicable Examination Requirements The requirements for the nonvisual non-destructive examinations (NDE) (ultrasonic and eddy current) performned on the Comanche Peak Unit 2 RPV head during the 2RF08 refueling outage are specified in the Order, Section IV, paragraphs C.(3) and C.(5)(b). Paragraph IV.C.(3) of the Order states in part: The requirements ofpara graph IV. C. (5)(b) must be completed at least once prior to February 1], 2008, and thereafter, at least every 4 refuieling outages or every 7 years, w4hichever occursIi rst." Paragraph IV.C.(5)(b) of the Order states: For each penetration, perform a nonvisual NDE in accordance with either ('u), (iui), or ('ii4): Ultrasonic testing of the RP V head penetration nozzle volume (i.e., nozzle base material from 2 inches above the hi ghest point of the root of the J-groove weld ('on a horizontal plane perpendicular to the nozzle axis) to 2 inches below the lowest point at the toe of the J-groove weld on a horizontal plane perpendicular to the nozzle axis (or the bottom of the nozzle if less than 2 inches [see Figure IV-I],); OR.from 2 inches above the highest point of 'the root of the i-groove weld (onl a horizontal plane perpendicular to the nozzle axis) to 1.0-inch below the lowest point at the toe qf the J-groove weld (on a horizonital plane perpendicular to the nozzle axis) and including all RPV head penetration nozzle surfaces below the J-groove weld that have an operating stress level (Including all residual and normnal operation stresses) qf 20 ksi tension and greater (see Figure JV-2,). In addition, an to TXX-06204 Page 2 of 13 Relaxation Request for Inspection Coverage from First Revised Order EA-03-009 assessnment shall be niade to determine i/ leakage has occurred into the annulus between the RPV head penetration nozzle and the RPV head lowt-alloyv steel. (i i) Eddy current testing or dye penetrant testing qf the entire wetted sturface of the J-groove weld and the wetted stuface of the RP Vhead penetration nozzle base material from at least 2 inches above the hi ghest point of the root of the J-groove weld ('on a horizontal plane perpendicular to the nozzle axis) to 2 inches below the lowest point at the toe of the J-groove weld on a horizontal plane perpendicular to the nozzle axis (or the bottom of the nozzle i/less than 2 inches fsee Figure IV-3j,); OR from 2 inches above the highest point of the root of the J-groove weld (on a horizontal plane perpendicular to the nozzle axis) to 1. 0-inch below the lowest point at the toe of the i-groove weld (on a horizontal plane perpendicular to the nozzle axis,) and including all RP Vhead penetration nozzle surfiices below the i-groove weld that have an operating stress level (including all residual and normal operation stresses) of 20 ksi tension and greater (see Figure IV-4). (Iiii) A combination of (i,) and (i'i) to cover equivalent volumes, surfaces and leak paths of the RP V head penetration nozzle base material and J-groove weld as described in ('i) and (ii,). Substitution of a portion of a volumetric exam on a nozzle with a sur/Žlce examination may be performed with the./bl/owing requirements:

1.

On nozzle material below the J-groove weld, both the outside diameter and inside diameter surfaces of the nozzle must be examined.

2.

On nozzle material above the i-groove weld, surface examination of the inside diameter surfiwe of 'the nozzle is permitted provided a surface examination of the i-groove weld is also performed. Requirement from Which Relaxation Is Requested In accordance with Section IV.F.(2) of the Order, relaxation from the above requirements is requested since compliance with the Order would result in a hardship or unusual difficulty without a compensating increase in the level of quality and safety. Relaxation is requested from Section IV.C.(5)(b)(i) of the Order to performn ultrasonic testing (UT) of the RPV head penetrations inside the tube fromn 2 inches above the i-groove weld to:

  • 2 inches below the lowest point of the toe of the i-groove weld (or the bottom of the nozzle if less than 2 inches) OR to TXX-06204 Page 3 of 13 Relaxation Request for Inspection Coverage from First Revised Order EA-03-009
  • 1.0-inch below the lowest point of the toe of the J-groove weld and including all RPV head penetration nozzle surfaces below the J-groove weld that have an operating stress level of 20 ksi tension and greater.

Based on the physical configuration of the nozzles and the lim-itations of the test equipment at Comanche Peak Unit 2, it is not possible to achieve the inspection coverage specified in Section IV.C.(5)(b)(i) of the Order for five RPV penetration nozzles on Comanche Peak Unit 2. Relaxation is requested to redefine the inspection area for the affected penetrations as "the volume of the penetration tube extending from 2 " above the J-groo ve weld down to the lowest elevation that can be practically inspected."

Reason for Request

The Comanche Peak Unit 2 RPV head penetration non-visual examinations were performed during the Spring 2005 (2RF08) refuel outage. The examinations were performed using Westinghouse/WesDyne/Tecnatom-equipment and procedures demonstrated through the Electric Power Research Institute (EPRI) Materials Reliability Project. Due to physical limitations and interferences associated with some of the penetrations, the examinations required by Section IV.C.(5)(b)(i) of the Order cannot be performed. The nozzle inspections of the volume from the i-groove weld root up to two inches above the weld and the leakage assessments required under Section IV, Paragraph C.(5)(b)(i) of the Order were satisfied for all penetrations. The lower nozzle inspection volume (one inch below the lowest point at the toe of the J-groove weld including all RPV head penetration nozzle surfaces of 20 ksi tension and greater) required under Section IV, Paragraph C.(5)(b)(i) of the Order were satisfied for all but 5 penetrations. For the lower portion of the penetration defined in Figure IV-2 of the Order, required coverage one inch below the lowest point of the i-groove weld toe could not be achieved for 5 penetrations (i.e., numbers 74, 75, 76, 77, and 78). Component Geometry For Comanche Peak Unit 2 all of the penetrations except for the Instrument Column penetrations had no threads or internal chamfer at the base of the tubes and the coverage met the intent of the Order, therefore, this discussion will be limited to the Instrument Column penetrations. The bottomn of each RPV Instrument Column head penetration nozzle includes a threaded region on outside diameter along with a chamfered area at the inside diameter from the bottom of the penetration tube (see Figure 1). In addition to the presence of the threaded and chamfered regions the 5 penetration tubes also have a threaded guide cone attached to the bottom of the penetration tube via the threaded connection along with a welded set screw and two tack welds. The distance from the top of the thread relief to the bottom of the fillet of the J-groove weld, identified as "A", the distance from the bottom of the fillet of the J-groove weld to the upper to TXX-06204 Page 4 of 13 Relaxation Request for Inspection Coverage from First Revised Order EA-03-009 edge of the chamnfered "A-B" in Figure 1, varies based on location of the penetration in the RPV head. These distances are generally longer for penetrations at "inboard" locations and become progressively shorter for penetrations located farther away from the center of the RPV head. At the 5 subject penetration nozzles (i.e., numbers 74, 75, 76, 77, and 78) the configuration is such that the distance from the lowest point at the toe of the i-groove weld to the bottom of the scanned region is less than the one inch lower boundary Ilimnit specified in section IV.C.5(b)(i) of the Order. Figure 1 Illustration of Axially and Circumnferenti ally Oriented Examination Coverage to TXX-06204 Page 5 of 13 Relaxation Request for Inspection Coverage from First Revised Order EA-03-009 .Examination Details The inspection system used for Comanche Peak Unit 2 consisted of two probes to perform UT inspection of the penetration nozzles. The first probe (Trinity Probe) was used to inspect nozzles that contained thermal sleeves (57 total) the required inspection coverage was achieved using this type of probe. The second probe type (Open Housing Probe) was used to inspect nozzles without thermnal sleeves (21 total). The 5 subject penetration nozzles used this type of probe. The vent line examination (I total) is not included in the discussion as this examination area has a different geometry that was not limited. The time of flight diffraction (TOFD) technique is a "pitch/catch" ultrasonic method, which uses two transducers (one a transmitter, and one a receiver) oriented along the vertical axis of the probe. The focus point of the TOMD beam is at the midpoint between the upper and lower transducers. Longitudinal waves are transmitted into the tube at an angle by the transmitter (T) and reflect off the backside of the tube to a receiver (R), as shown in path "1I - 2" in Figure 1. A lateral wave also travels on the tube inside diameter (ID) surface between the transmitter and receiver as shown in path "3" in Figure 1. ID TOFD coverage is provided by the lateral wave to the elevation of the chamfer of the tube on the ID surface. With a ci rcumferenti ally oriented TOFD transducer pair, included in the Open Housing Scanner, outside diameter (GD) coverage is extended to the elevation of the top of the chamfer as shown in path "4" in Figure 1. In the threaded region, cracks extending deeper than the threads will be detected. Uphill Coverage exia to' A Downhill Coverage I.D. Chamnfer Figure 2 Open Housing Probe Circumferential UT Coverage to TXX-06204 Page 6 of 13 Relaxation Request for Inspection Coverage from First Revised Order EA-03-009 As stated above in addition to the axially oriented TOMD transducers the Open Housing Probe has circumferentially oriented TOFD transducers. This circumferentially oriented TOFD signal allows the Open Housing Probe to inspect the tube down to the top of the ID chamfer. Also, with the Open Housing Probe's circumferentially oriented transducers, the TOFD beam is not interrupted by the OD thread relief. The dimensions listed in Table I reflect the circumferential TOMD transducer coverage limitation to the chamfered region. The shaded areas indicate the portions of the tube that cannot be inspected see Figure 3 below. Axially Circumnferentially Oriented Oriented (:)OFD 00 -- 0 (,TOFD Figure 3 Open Housing Probe Coverage Limitations The Order allows provisions for dye penetrant inspection. However, dye penetrant inspection would require extensive work under and around the RPV head. Based on electronic dosimetry readings from the examiner performning the vent nozzle manual inspection, the general area radiation level under the Unit 2 head during 2RF08 was approximately 3 R/hr. General contact readings at the nozzles for Comanche Peak Unit 2 are historically 5 R/hr. Section IV.C.5(B)(iii)l. of the Order requires penetrant inspection on both the inside and outside diameter surfaces in order to be considered an acceptable substitution for ultrasonic examination. The threaded region on the outside diameter of the penetration tubes along with the presence of the welded guide funnels on penetration tube ends makes a dye penetrant examination on the lower section of the tube impractical. Therefore, performing dye penetrant inspections on the bottom nozzle area would result in significant radiation exposure to personnel without a compensating increase in the level of quality or safety. Table 1 contains inform-ation specific to the five penetrations for which relaxation is being requested. The values for Control Rod Drive Housing (CRDM) penetration hoop stress distributions at a point where the operating stress levels are less than 20 ksi tension (i.e., 20 Ksi Line) were extrapolated from the associated graphs contained in Figures 6 and 7, which are also contained in Appendix A of Topical Report, WCAP-1I6397-P, Revision 0, "Structural Integrity to TXX-06204 Page 7 of 13 Relaxation Request for Inspection Coverage from First Revised Order EA-03-009 Evaluation of'Reactor Vessel Upper Head Penetrations to Support Continued Operation: Comanche Peak Units 1 and 2, " dated June 2005 (Enclosure 1). Actual Scan 20 Ksi line Penetration Intersection Length (A-B (inches below J-Nozzle No. Angle from Figure 1 Groove Weld __________Inches) 74 48.7 0.81 0.29 75 48.7 0.30 0.29 76 48.7 0.73 0.29 77 48.7 0.33 0.29 78 48.7 0.36 0.29 Table 1 Penetrations with Limited Examination Volume (Actual scan lengths which were less than one inch) Figure 4 Penetration Angle (typical) to TXX-06204 Page 8 of 13 Relaxation Request for Inspection Coverage from First Revised Order.EA-03-009 Proposed Alternative and Basis for Use TXU Power proposes to define the lower boundary of the inspection volume for the affected RPV head penetration nozzles as: "the ivolume of the penetration tube extending frolm 2 " above the J-groove weld down to the lowest elevation that can be practically inspected. " TXU Power perforiried UT examinations to the maximum extent possible and, for Comanche Peak Unit 2, meets all requirements of the Order with the exception of the five penetration tubes previously noted. TXU Power was unable to completely comply with the requirements for UT inspection for five RPV penetration nozzles below the i-groove weld, due to the physical configuration of the nozzles and the limitations of the test equipment. The bottom ends of these nozzles are externally threaded and internally tapered. Loss of UT probe coupling due to the internal taper and/or disruption of the UT signal due to the external thread prevented UT data acquisition in a zone extending to approximately one-inch above the bottom of each nozzle. Testing of portions of the nozzle significantly below the J-groove weld is not significant to the phenomena of concern. The phenomena that are of concern are leakage through the i-groove weld and circumnferential cracking in the nozzle above the J-groove weld. This is appropriately reflected in the requirements of the Order that the testing extend to two inches above the J-groove weld. However, the Order also requires that testing be extended to: 0 2 inches below the lowest point of the toe of the i-groove weld (or the bottom of the nozzle if less than 2 inches) OR 1.0-inch below the lowest point at the toe of the J-groove weld and including all RPV head penetration nozzle surfaces below the i-groove weld that have an operating stress level of 20 ksi tension or greater. The nozzle is essentially an open-ended tube, and the nozzle wall below the i-groove weld is not part of the reactor coolant system pressure boundary. The proposed inspection coverage is adequate because the cited inspection limitation for the RPV head penetration nozzles does not preclude full UT examination coverage of the portions of these nozzles that are of primary interest. This can be assumed because:

  • UT of the most highly stressed portion of the nozzle (the weld heat affected zone) is unaffected by this limitation.

to TXX-06204 Page 9 of 13 Relaxation Request for Inspection Coverage from First Revised Order EA-03-009 "UT of the interference fit zone above the weld (for leakage assessment) is unaffected by this limitation, and cracks initiating in the unexamined bottom portion (non-pressure boundary) of the nozzle would be of minimal safety significance with respect to pressure boundary leakage or nozzle ejection.

  • Since this portion of the nozzle is below the pressure boundary, any cracks would have to grow through a significant examnined portion of the tube to reach the pressure boundary.

This proposed alternative is consistent with the analysis submitted in the industry topical report MRP-95, "Materials Reliability Program: Generic Evaluation of Examination Coverage Requirements for Reactor Pressure Vessel Head Penetration Nozzles," and the site-specific analysis in WCAP-l6397-P. The zones of inspection selected are such that the stresses in the remaining uninspected zones are at levels for which Primary Water Stress Corrosion Cracking (PWSCC) is considered highly unlikely. The major inherent conservatisms in WCAP-163 97-P are summarized below: Conservatism in Assumed Crack Geometry It is understood that high stresses, on the order of the material yield strength, are necessary to initiate PWSCC. There is no known case of stress corrosion cracking of Alloy 600 below the yield stress. The yield strengths for wrought Alloy 600 head penetration nozzles are in the range of 37 ksi to 65 ksi. Weld metal yield strengths are generally higher. The yield strength of the head penetration nozzles for Comanche Peak Unit 2 varies fr-om 36 ksi to 46.5 ksi. The stress level of 20 ksi is a conservative value below which PWSCC initiation is extremely unlikely. Therefore, the assumption of any PWSCC crack initiation in the region of the penetration nozzle with a stress level of 20 ksi or less is conservative. The assumption of a through-wall flaw in these unlikely PWSCC crack initiation regions of the head penetration is an important additional conservatism, since the penetration tubes were inspected with maximum achievable coverage on the tube ID. Flaw Propagation Calculations and Examination Coverage A structural integrity evaluation was perfonr-ned for the Comanche Peak Unit I and Unit 2 reactor vessel head penetrations under WCAP-1 6397-P. The basis of this analysis is a detailed three-dimensional elastic-plastic finite element stress analysis of several penetration locations, which considers all the pertinent loadings on the penetration, and a fracture analysis using the crack growth rates recommended by the EPRI Topical Report "Materials Reliability Program (MRP) Crack Growth Rates for Evaluating Prirnaiy Water Stress Corrosion Cracking (PWSCC) of Thick Wall Alloy 600 Material (MRP-55) Revision I." A series of crack growth calculations were performed presuming a flaw where the lower extremity of this initial through wall flaw is to TXX-06204 Page 10 of 13 Relaxation Request for Inspection Coverage from First Revised Order EA-03-009 conservatively postulated to be located on the penetration nozzle where either the inside or outside surface hoop stress drops below 0 ksi. The results of these calculations provided the estimated remaining operating cycles that would elapse before a postulated flaw in the unexamined area of the penetration nozzle would propagate into the pressure boundary formed by the i-groove weld. The postulated flaw at the lower extent of coverage was located on the flaw growth curve associated with the penetration angle. For those penetrations that do not have a flaw growth curve specific to the tube penetration angle, a conservative curve (nearest the lower penetration angle) was used. The time it would take for the postulated flaws to intersect the weld metal for the minimum coverage achieved was then determined. Comanche Peak Unit 2 past operating cycles have been approximately 18 months (1.5 calendar years or 1.34 Effective Full Power Years (EFPY) per cycle based on historical data). Comanche Peak Unit 2 will remain on 18-month cycles based on the current long-term schedule. Conservatively using 1.45 EFPY for the remaining four operating cycles until the next required examination, there are 5.8 EFPY between the 2RF08 examinations until the next scheduled examination required by the Order. In accordance with the current Order requirements (perform examination within every four refueling outages or seven years, whichever occurs first), the next inspection for the Comanche Peak Unit 2 RPV penetrations must be completed by the 2RF 12 outage, which is currently scheduled in Spring of 201 1. Based on 2RF08 examination results (see Table 1), the worst-case minimum distance below the i-groove weld to the top of the zone that could not be inspected was determined to be 0.30 inches on the downhill side of the penetration nozzle #75. To account for the inspection tolerance of the inspection equipment (0.04 inches), an axial through-wall flaw was conservatively postulated to be located at 0.20 inches below the i-groove weld in the crack propagation calculation for the downhill side of the penetration nozzle. Using the applicable crack growth rate for the penetration (Figure 5), it would take 6.5 EFPY for the postulated flaw to propagate from that location to the bottomn of the J-groove weld, which would occur after the next scheduled inspection. For the subject penetrations that TXU Power is seeking relaxation, Figure 5 (WCAP-1I6397-P, Figure 6-16) provide results of the calculation. The calculation demonstrates that the minimum time for a flaw to propagate from that location to the bottom of the i-groove weld would be greater than four operating cycles. The results of the flaw propagation calculation indicate that, even if a flaw were to occur in the region of the penetration nozzle not being inspected, there would be adequate opportunity for detection prior to the crack reaching the reactor coolant system pressure boundary. The results demonstrate that the extent of the proposed inspection coverage would provide reasonable assurance of the structural integrity of the Unit 2 RPV head penetration nozzles and the J-groove welds. to TXX-06204 Page 11I of 13 Relaxation Request for Inspection Coverage from First Revised Order EA-03-009 Conclusion In all cases, the measured coverage is adequate to allow Comanche Peak Unit 2 to continue to operate prior to the hypothetical flaws reaching the J-groove weld. In accordance with the current Order requirements, the next examination required for the Comanche Peak Unit 2 RPV penetrations would be completed prior to flaw propagation into J-groove welds. to TXX-06204 Page 12 of 13 Relaxation Request for Inspection Coverage from First Revised Order EA-03-009 2.0 E .2 1.0 E 0 0.5 M- 0.5 0) B 0ý -1.0 0 1 2 3 4 5 6 7 8 9 1 Time (Effective Full Power Years) 11 12 13 14 15 16 17 Figure 5 Through-Wall Longitudinal Flaws Located in the 48.70 CRDM Row of Penetrations, Downhill Side Comanche Peak Units I and 2 Crack Growth Predictions for to TXX-06204 Page 13 of 13 Relaxation Request for Inspection Coverage from First Revised Order EA-03-009 70,000 60.000 20,000 0. 10,0 _10.000 -20,000 -30.000 0.0 0.5 1.0 1.5 2.0 2.5 Distance from Bottom of Weld (in) - Inside -{'--Outside Figure 6 Hoop Stress Distribution Downhill Side (48.70 CRDM Penetration Nozzle) 60,000 50.000 40,000 30.000 ~.20,000 S10,000 0 0 0 -10,000 -20.000 -30.000 -40,000 0.0 0.5 1.ý0 1.5 2.0 2.5 3.0 3,5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 Distance from Bottom of Weld (in) Inside --Outside Figure 7 Hoop Stress Distribution Uphill Side (48.70 CRDM Penetration Nozzle) to TXX-06204 Application for withholding for WCAP-163)97-P, Revision 0

1. Westinghouse Letter CAW-052032 and Affidavit
2. Proprietary / Copyright Notice

efWestinghouse Westinghouse Electric Company Nuclear Services P.O. Box 35 5 Pittsburgh, Pennsylvania 15230-0355 USA U.S. Nuclear Regulatory Commission Document Control Desk Washington, DC 20555-0001 Direct tel: Direct fax: e-mail: (412) 374-4643 (412) 374-4011 greshaj a@westinghouse. corn Our ref: CAW-05-2032 July 20, 2005 APPLICATION FOR WITHHOLDING PROPRIETARY INFORMATION FROM PUBLIC DISCLOSURE

Subject:

WCAP-16397-P, Revision 0, "Structural Integrity Evaluation of Reactor Vessel Upper Head Penetrations to Support Continued Operation: Comanche Peak Units I and 2," June 2005 (Proprietary) The proprietary information for which withholding is being requested in the above-referenced report is further identified in Affidavit CAW-05-2032 signed by the owner of the proprietary information, Westinghouse Electric Company LLC. The affidavit, which accompanies this letter, sets forth the basis on which the information may be withheld from public disclosure by the Commission and addresses with specificity the considerations listed in paragraph (b)(4) of 10 CFR Section 2.390 of the Commission's regulations, Accordingly, this letter authorizes the utilization of the accompanying affidavit by TXU Power. Correspondence with respect to the proprietary aspects of the application for withholding or the Westinghouse affidavit should reference this letter, CAW-05-2032, and should be addressed to J. A. Gresham, Manager, Regulatory Compliance and Plant Licensing, Westinghouse Electric Company LLC, P.O. Box 355, Pittsburgh, Pennsylvania 15230-0355. Very truly yours, J. A. Gresham, Manager Regulatory Compliance and Plant Licensing Enclosures cc: B. Beniney L. Feizollahi A BNFL Group company

CAW-05-2032 bcc: J. A. Gresham (ECE 4-7A) I L R. Bastien, I L (Nivelles, Belgium) C. Brinkman, I L (Westinghouse Electric Co., 12300 Twinbrook Parkway, Suite 330, Rockville, MD 20852) RCPL Administrative Aide (ECE 4.-7A) I L, IlA (letter and affidavit only) A BNFL Group company

CAW-05-2032 AFFIDAVIT COMMONWEALTH OF PENNSYLVANIA: ss COUNTY OF ALLEGHENY: Before me, the undersigned authority, personally appeared J. S. Galembush, who, being by me duly sworn according to law, deposes and says that he is authorized to execute this Affidavit on behalf of Westinghouse Electric Company LLC (Westinghouse), and that the averments of fact set forth in this Affidavit are true and correct to the best of his knowledge, information, and belief: Sworn to and subscribed before me this 2A day o f , 2004 Notary Public Notarial Seal Sharon L. Rod, Notary Public Monroeville Boro, Alleghen C~ounty My Commission Expires January 29, 2007 member, Pennsylvania Association of Notaries

2 CAW-05-2032 (1) 1 am Customer I" Leader in Nuclear Services, Westinghouse Electric Company LLC (Westinghouse), and as such, I have been specifically delegated the function of reviewing the proprietary information sought to be withheld from public disclosure in connection with nuclear power plant licensing and rule making proceedings, and am authorized to apply for its withholding on behalf of Westinghouse. (2) 1 am making this Affidavit in conformance with the provisions of 10 CFR Section 2.390 of the Commission's regulations and in conjunction with the Westinghouse "Application for Withholding" accompanying this Affidavit. (3) 1 have personal knowledge of the criteria and procedures utilized by Westinghouse in designating information as a trade secret, privileged or as confidential commercial or financial information. (4) Pursuant to the provisions of paragraph (b)(4) of Section 2.390 of the Commission's regulations, the following is furnished for consideration by the Commission in determining whether the information sought to be withheld from public disclosure should be withheld. (i) The information sought to be withheld from public disclosure is owned and has been held in confidence by Westinghouse. (ii) The information is of a type customarily held in confidence by Westinghouse and not customarily disclosed to the public. Westinghouse has a rational basis for determining the types of information customarily held in confidence by it and, in that connection, utilizes a system to determine when and whether to hold certain types of information in confidence. The application of that system and the substance of that system constitutes Westinghouse policy and provides the rational basis required. Under that system, information is held in confidence if it falls in one or more of several types, the release of which might result in the loss of an existing or potential competitive advantage, as follows: (a) The information reveals the distinguishing aspects of a process (or component, structure, tool, method, etc.) where prevention of its use by any of

3 3 CAW-05-2032 Westinghouse's competitors without license from Westinghouse constitutes a competitive economic advantage over other companies. (b) It consists of supporting data, including test data, relative to a process (or component, structure, tool, method, etc.), the application of which data secures a competitive economic advantage, e.g., by optimization or improved marketabil ity. (C) Its use by a competitor would reduce his expenditure of resources or improve his competitive position in the design, manufacture, shipment, installation, assurance of quality, or licensing a similar product. (d) It reveals cost or price information, production capacities, budget levels, or commercial strategies of Westinghouse, its customers or suppliers. (e) It reveals aspects of past, present, or future Westinghouse or customer funded development plans and programs of potential commercial value to Westinghouse. (f) It contains patentable ideas, for which patent protection may be desirable. There are sound policy reasons behind the Westinghouse system which include the following: (a) The use of such information by Westinghouse gives Westinghouse a competitive advantage over its competitors. It is, therefore, withheld from disclosure to protect the Westinghouse competitive position. (b) It is information that is marketable in many ways. The extent to which such information is available to competitors diminishes the Westinghouse ability to sell products and services involving the use of the information. (C) Use by our competitor would put Westinghouse at a competitive disadvantage by reducing his expenditure of resources at our expense.

4 4 CAW-05-2032 (d) Each component of proprietary information pertinent to a particular competitive advantage is potentially as valuable as the total competitive advantage. If competitors acquire components of proprietary information, any one component may be the key to the entire puzzle, thereby depriving Westinghouse of a competitive advantage. (e) Unrestricted disclosure would jeopardize the position of prominence of Westinghouse in the world market, and thereby give a market advantage to the competition of those countries. (f) The Westinghouse capacity to invest corporate assets in research and development depends upon the success in obtaining and maintaining a competitive advantage. (iii) The information is being transmitted to the Commission in confidence and, under the provisions of 10 CFR Section 2.390, it is to be received in confidence by the Commission. (iv) The information sought to be protected is not available in public sources or available information has not been previously employed in the same original manner or method to the best of our knowledge and belief. (v) The proprietary information sought to be withheld in this submittal is that which is appropriately marked in WCAP-1 6397-P, Revision 0, "Structural Integrity Evaluation of Reactor Vessel Upper Head Penetrations to Support Continued Operation: Comanche Peak Units I and 2," June 2005 (Proprietary) being transmitted by the TXU Power letter and Application for Withholding Proprietary Information from Public Disclosure, to the Document Control Desk. The proprietary information as submitted for use by Westinghouse for Comanche Peak Units I and 2 is expected to be applicable for other licensee submittals in response to certain NRC requirements for justification of the use of fracture mechanics analyses to support continued safe operation of Comanche Peak Units 1 or 2 with the presence of a crack in a control rod drive head penetration. This information is part of that which will enable Westinghouse to:

't i 5 CAW-05-2032 (a) Determine the allowable time of safe operation if cracks are found. (b) Assist the customer to obtain NRC approval. Further this information has substantial commercial value as follows: (a) Westinghouse plans to sell the use of similar information to its customers for purposes of meeting NRC requirements for licensing documentation. (b) Westinghouse can sell support and defense of continued safe operation with the presence of cracks in a control rod drive head penetration. Public disclosure of this proprietary information is likely to cause substantial harm to the competitive position of Westinghouse because it would enhance the ability of competitors to provide similar support documentation and licensing defense services for commercial power reactors without commensurate expenses. Also, public disclosure of the information would enable others to use the information to meet NRC requirements for licensing documentation without purchasing the right to use the information. The development of the technology described in part by the information is the result of applying the results of many years of experience in an intensive Westinghouse effort and the expenditure of a considerable sum of money. In order for competitors of Westinghouse to duplicate this informnation, similar technical programs would have to be performed and a significant manpower effort, having the requisite talent and experience, would have to be expended. Further the deponent sayeth not.

PROPRIETARY TINFORMATION NOTICE Transmitted herewith are proprietary and/or non-proprietary versions of documents furnished to the NRC in connection with requests for generic and/or plant-specific review and approval. In order to conform to the requirements of 10 CFR 2.390 of the Commission's regulations concerning the protection of proprietary information so submitted to the NRC, the information which is proprietary in the proprietary versions is contained within brackets, and where the proprietary information has been deleted in the non-proprietary versions, only the brackets remain (the informnation that was contained within the brackets in the proprietary versions having been deleted). The justification for claiming the information so designated as proprietary is indicated in both versions by means of lower case letters (a) through (f) located as a superscript immediately following the brackets enclosing each item of information being identified as proprietary or in the margin opposite such information. These lower case letters refer to the types of informnation Westinghouse customarily holds in confidence identified in Sections (4)(ii)(a) through (4)(ii)(f) of the affidavit accompanying this transmittal pursuant to 10 CFR 2.390(b)(1). COPYRIGHT NOTICE The reports transmitted herewith each bear a Westinghouse copyright notice. The NRC is permitted to make the number of copies of the information contained in these reports which are necessary for its internal use in connection with generic and plant-specific reviews and approvals as well as the issuance, denial, amendment, transfer, renewal, modification, suspension, revocation, or violation of a license, permit, order, or regulation subject to the requirements of 10 CFR 2.390 regarding restrictions on public disclosure to the extent such information has been identified as proprietary by Westinghouse, copyright protection notwithstanding. With respect to the non-proprietary versions of these reports, the NRC is permitted to make the number of copies beyond those necessary for its internal use which are necessary in order to have one copy available for public viewing in the appropriate docket files in the public document room in Washington, DC and in local public document rooms as may be required by NRC regulations if the number of copies submitted is insufficient for this purpose. Copies made by the NRC must include the copyright notice in all instances and the proprietary notice if the original was identified as proprietary.}}

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