ML20205C725
| ML20205C725 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 03/26/1999 |
| From: | Terry C, Woodlan D TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| TXX-99082, NUDOCS 9904010341 | |
| Download: ML20205C725 (11) | |
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Log
- TXX-99082 File
- 10010.1,905.2 (clo)
Ref.
- 10CFR50.55(a)(3)(i) 7UELECTRIC 10CFR50.55(g)(5)(iii)
- c. u n,rry Senior Vice President
& PrincipalNuclear Officer March 26,1999 U. S. Nuclear Regulatory Commission j
Attn: Document Control Desk I
Washington, DC 20555
SUBJECT:
COMANCHE PEAK STEAM ELECTRIC STATION (CPSES)
DOCKET NOS. 50-445 AND 50-446 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING UNIT 1 AND UNIT 2 INSERVICE INSPECTION PROGRAM RELIEF REQUESTS E-1 AND L-1 REF: 1) TU Electric Letter, logged TXX-98041, from C. L. Terry, dated February 20,1998.
Gentlemen:
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On February 20,1998, TU Electric submitted Unit 1 and Unit 2 Relief Requests E-1 and L-1 (Reference 1). On March 19,1999, the NRC staff (Tim Polich et al.) and TU Electric (Ben Mays et al.) participated in a phone conference call to discuss open issues related to th subject relief requests. TU Electric agreed to provided a written response by March 26,1999, to requests for additionalinformation (RAl) identified during the March 19,1999, phone conference call. TU Electric's response to the RAIis Attached.
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9904010341 990326 PDR ADOCK 05000445 G
PDR c.10022
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COMANCHE PEAK St LAM ELECTRIC STATION P.O. Box 1002 Glen Rose. Texas 76043-1002
TXX-990.82 Pege 2'of 2 If you have any questions please contact Ben Mays at (254) 897-6816 or Carl Corbin at (254) 897-0121.
This communication contains no new licensing basis commitments regarding Comanche Peak Steam Electric Station Units 1 and 2.
Sincerely, C. L. Terry By:
D. R. Woodlan Docket Licensing Manager CBC/cbc -
Attachment c-E. W. Merschoff, Region IV J. I. Tapia, Region IV T. J. Polich, NRR Resident inspectors, CPSES G. Bynog, TDLR J. C. Hair, ANil i
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Attachment t2 TXX-99082 Page 1 of 9 CPSES Response to the NRC RAl's regarding Units 1 and 2 Relief Requests E-1 and L-1 l
NRC RAI 1.
In the licensee's submittal, the proposed alternative, as stated, is to use the " current ASME approved rewrite" of Subsections IWE and IWL. For the i
staff's preliminary evaluation, it was assumed that the licensee will use the latest published Edition of the Code. Verify that Comanche Peak intends to use the now published 1998 Edition of ASME Section XI, Subsectiors i
IWE and IWL. If not the 1998 Edition, what published Edition / Addenda of Section XI provides the overall basis for the proposed alternative?
TU Electric Response:
Yes, TU Electric intends to use the now published 1998 Edition of ASME Section XI, Subsections IWE and IWL.
NRC RAI 2.
The 1998 Edition eliminates the weld accessibility requirements of IWE-1231(a)(3) and IWE-1232(a)(3). Consequently,if a repair / replacement activity is performed, there is no requirement to maintain accessibility to the subject welds for examination. Explain why this change should be considered acceptable following a repair / replacement activity.
TU Electric Response.
The NRC Rulemaking (Page 41308 of Reference 1) states in part,"makes the examinations of Subsection IWE, Examination Category E-B (pressure retaining welds) and Subsection iWE, Examination Category E-F (pressure retaining dissimilar metal welds) optional. The NRC staff concludes that requiring these examinations is not appropriate. There is no evidence of problems associated with welds of this type under the given operating conditions".
As stated in the IWE commentary (Reference 2), " Subsection IWE originally contained requirements for weld examinations. Single welded butt joints had been required to remain accessible from the weld side for examination.
Subsection IWE has been revised and no longer contains any specific weld examination requirements. Therefore, accessibility requirements for embedded single sided butt joints have been eliminated" Pressure-retaining welds have been removed as a separate Examination Category in the 1998 Edition. A requirement for a general visual examination of pressure boundary welds is still contained in the 1998 Edition of Table IWE 2500-1, footnote 1 for item No. E1.10, Pressure Retaining Boundary. The 1998 Edition of IWE-1231 and IWE-1232 provide accessibility requirements for the containment pressure-retaining boundary.
l Therefore, the resulting change is consistent with NRC Rulemaking that removes i
the emphasis from weld based examinations.
f Attachmint to TXX 99082 Page 2 of 9 CPSES Response to the NRC RAl's regarding Units 1 and 2 Relief Requests E-1 and L-1 NRC RAI 3.
1998 Section XI generally refers to IWA-2000, Examination and inspection, when defining the general requirements for examinations to be performed, and for the qualification of examination personnel. The licensee's proposed alternative removes the IWA-2300 requirement to certify NDE personnel to CP-189. In addition, new Code examinations (Gen 6ral Visual and Detailed Visual) have been intro 1uced. The definition of the new Code examinations has been left up to individual licensee's, and a licensee would be allowed to define how personnel performing these examinations are to be qualified. It is presently unclear how owner-defined visual examination programs, including items such as illumination and resolution requirements, acceptance criteria, and minimum personnel qualifications, j
may be individually developed and the necessary level of consistency maintained industry-wide. The staff considers this changed (1998 Edition) requirement to be inconsistent with other Code visual examination prerequisites, and too generic in nature.
To establish that the licensee's alternative provides an acceptable level of quality and safety, details of the Comanche Peak General and Detailed Visual examination program must be evaluated. Please submit the visual program, including attributes such as:
[a]
Details of the owner-defined General Visual acceptance criteria that will be used to examine general containment surfaces, containment welds, bolting, moisture barriers, dissimilar metal welds, etc.
[b]
Describe the Detailed Visual criteria used to address augmented examinations.
[c]
Discuss how these examinations will provide the same level of quality and safety that is provided by the VT 1 and VT-3 examinations required by the 1992 Edition and Addenda.
[d]
Describe the qualification requirements for personnel performing containment visual examinations.
[e]
Describe the qualification requirements for personnel performing augmented ultrasonic examination of containment surfaces.
TU Electric Response:
[a].
The TU Electric Containment Visual Examination Program will address recording criteria that if exceeded requires review by the Responsible Individual for disposition in accordance with applicable site approved programs.
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1 Attachment to TXX-99082
.Page 3 of 9
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CPSES Response to the NRC RAl's regarding Units 1 and 2 Relief Requests E 1 and L-1 As discussed in the responses to question No.'s 2 and 9, the 1998 Edition of IWE and the NRC Rulemaking remove the emphasis from weld based examinations. Therefore, containment welds and dissimilar metal welds will be examined by General Visual examination to the same criteria as general containment surfaces. For non-coated containment surfaces this criteria was developed from VT-3 procedures that are used for examination of ASME Code Class 1,2 and 3 components such as '.he reactor vessel interior, pump casings and valve bodies. This includes -
examining for cracking, discoloration, structural distortion, weer, pitting, corrosion, gouges, dents or other surface discontinuities. For coated containment surfaces the record:ng criteria was developed from the Comanche Peak Coatings Program. This includes examining for flaking, blistering, peeling, discoloration or otner signs of distress.
As discussed in the response to question No.'s 7 and 10, pressure retaining bolting will be examined by General Visual examination. The recording criteria was developed from the VT-1 procedure that is used for ASME Code Class 1 bolting. This includes examining for: r.onaxial flaws greater than 1/4 inches in leng+h; axial flaws greater than 1 inch in length; more than one deformed or sheared thread in the zorw of thread engagement of bolts, studs or nuts; localized general corrosion that exceeds the thread root depth; bending, twisting or deformation of bolts or studs to the extent that assembly or disassembly is impaired; missing or loose bolts, studs, nuts or washers; fractured bolts, studs or nuts; degradation of protective coatings on bolting surfaces.
As discussed in the response to question No. 7, moisture barriers will be examined by General Visual examination. Moisture barriers will be examined for tears, cracks or other damage that permits intrusion of moisture through the barrier.
(b)
Detailed Visual examination criteria is developed from the VT-1 and VT-3 procedures that are used for examination of ASME Code Class 1,2 and
' 3 components. This includes examining coated and non-coated containment surfaces, bolting and moisture barriers for the same attributes addressed in 3(a] above.
(c]
The VT-3 and VT-1 inspections have been replaced by Owner (Responsible Individual) defined general and detailed visual examinations respectively. However, the definition of critical examination items and the list of critical examination attributes have not changed. The 1998 Edition provides specific examples of unacceptable conditions in IWE-2300 that were previously contained in IWE-3500. The general and detailed visual examinations are essentially equivalent to the VT-3 and VT-1 examinations in terms of assessing the structural integrity and potential for degradation to the containment system. Tne use of owner defined
r Attachment ts TXX-99082 Page 4 of 9 CPSt:$ Response to the NRC RAl's regarding Units 1 and 2 Relief Requests E-1 and L-1 examination methods allows for the involvement of qualified engineering personnel with backgrounds in areas such as containment coatings, Maintenance Rule, Appendix J, containment design, materials engineering and containment degradation mechanisrr.s. Procedures for inspection ard qualification are developed by a TU Electric NDE Level 111.
Procedures iWst be demonstrated to the ANil for capability to detect flaws and degradation levels as defined in the inspection procedures.
(d]
Personnel performing containment visual examinations will be qualified to a program developed specifically for containment examinations. As stated in the IWE (Reference 2)"Because VT-1 and VT-3 visual examination requirements have been deleted and replaced by the general and detailed visual examinations in Subsection IWE, NDE personnel need not perform these examinations ",.e general and detailed visual examinations may be performed oy engineering personnel. However, the conduct of these visual examinations must be directed by the RPE or other knowledgeabie individual." The containmer; visual examination program is developed from the guidelines of ASNT SNT-TC-1 A and ANSI N45.2.6 but is focused on visual examination arJ in particular items important to containment integrity. The SNT-TC-1 A Recommended Practice invoked by the 1986 Edition of ASME Section XI (Code of record for CPSES Units 1 and 2) for ASME Code Class 1,2 and 3 ISI examinations does not specifically address visual examinations. The required involvement of the Responsible Individual assures testing and qualification reviews will be performed such that personnel receiving conte nment visual examination certification will have a " demonstrated skill, demonstrated knowledge, documented training, and documented experience required to properly perform the duties of a specific job" as required by SNT-TC-1 A. Procedures for inspection and qualification are developed by a 7U Electric NDE Level 111. Procedures must be demonstrated to the ANil for capability to detect flaws and degradation levels as defined in the inspection procedures.
[e]
Personne) performing augmented ultrasonic examinations of containment surfaces will be qualified in accordance with written practices meeting the requirements of ASNT SNT-TC-1 A and ASME Section Xi(Edition and Addenda as applicable to the TU Electric ISI Program Plans, currently the 1988 Ed. no Ad.).
NRC RAI 4.
The 1998 Edition added paragraph IWE 2412(b) to define the examination schedule requirements if items or welds are added to the Inspection Program. Explain the circumstances that would necessitate adding welds or components to the Inspection Program of Subsection IWE. How does adding welds or components in the Subsection IWE Inspection Program differ from adding welds or components as part of a plant modification for other Class 1,2 or 3 ISI activities?
f I
l Attachment to TXX-99082 a
Nge 5 of 9 CPSES Response to the NRC RAl's regarding Units 1 and 2 Relief Requests E-1 and L-1 TU Electric Response:
It is not currently planned that any items would be added to the IWE Inspection Program. However, if items were added for any reason the 1998 Edition of IWE-2412(b) provides requirements where none previously 6. :isted in the '92 Addenda of IWE. The administrative methodology for adding items to the IWE program will be essentially the same as that for adding items to the ASME Code Class 1,2 or 3 ISI Program. The Comanche Peak ISI Program for ASME Code Class 1,2 and 3 components uses the 1986 Edition, no Addenda, of ASME Section XI which does not address the specific scheduling details contained in
'he later IWB, C, D and E Code Editions.
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NRC RAI 5.
The 1992 Edition, Subsections IWB-3100, !WC-3100, and IWE-3100 have paragraphs for inservice examinations stating that the licensee's repair / replacement program and reexamination results shall be subject to review by the enforcement authority. Additionally, evaluation analyses of flaws or areas of degradation found acceptable by engineering evaluation l
shall be submitted to, or may be subject to review by, the regulatory authority. The 1998 Edition has systematically removed these paragraphs from IWE and IWL (i.e., lWE-3415, IWE-3125, IWL-3320). The licensee's comment regarding the significance of these changes was that "there were no submittal or retention requirements changed by the deletion of the subparagraph." Explain why similar requirements remain for Class 1,2 and 3, yet are eliminated in IWE and lWL.
TU Electric Response:
The NRC Ru:emaking (Page 41312 of Reference 1) states in part, " Licensees do not have to submit to the NRC staff for approval of their containment inservice inspection program which was developed to satisfy the requirements of Subsection IWE and Subsection IWL with specified modifications and a limitation. The program elements and the required documentation shall be maintained on site for audit.".
Paragraphs IWE-3115 (typo in NRC question no. 5 shows IWE-3415), IWE-3125 and IWL-3320 from the '92 Addenda stated that certain documentation is
" subject to review" by the enforcement authorities and or regulatory authorities having jurisdiction at the plant site. It is TU Electric's understanding that ASME Section XI documentation is required to be maintained and is " subject to review" at any time. Changing the words from the '92 Addenda to the 1998 Edition does not alter our quality assurance methods for the retention of safety related records. Additionally, the change from the '92 Addenda to the 1998 Edition does not alter the involvement of the Authorized Nuclear Inservice Inspector for repair / replacement activities which are defined in IWA-4000 and IWA-2110 l
l (Duties of the inspector) j
Attachment t2 TXX-99082 Page 6 of 9 CPSES Response to the NRC RAl's regarding Units 1 and 2 Relief Requests E-1 and L-1 s
As stated in the commentaries, Subsections IWE and IWL depart from the
" standard" format ASME Code users have become accustomed to for ASME Code Class 1,2 and 3 components. The evaluation analyses of flaws as used in IWE and IWL is one of those areas. ASME Code Class 1,2 and 3 evaluations can involve detailed fracture mechanics calculations that are not applicable for IWE and IWL evaluations. In addition to normal TU Electric records retention, the NRC Rulemaking (Reference 1) provides requirements for inclusion of evaluations in the ISI Summary Report. The NRC Rulemaking (Page 41312 of
- Reference 1) states in part, "For each flaw or area of degradation identified which exceeds acceptance standards, the licensee shall provide the following in tm 6! 3ummary Report required by IWA-6000: (i) A description of each flaw or area, f.cluding the extent of degradation, and the condition that led to the degradation; (ii) The acceptability of each flaw or area and the need for additional examinations to verify that similar degradation does not exist in similar components, and; (iii) A description of necessary corrective actions."
NRC RAI 6 IWE-3500 of the 1992 Code describes general anomalies for visual examinations of containment components. If the descr: bed anomalies are discovered, the areas that are suspect shall be accepted by engineering evaluation or corrected by a repair / replacement activity. The 1998 Code has removed the requirement for engineering evaluation if the suspect area does not meet the acceptance standard for containment surfaces requiring augmented examination. Explain why the engineering evaluation is removed from IWE-3511.2, Visual Examination of Coated and Noncoated Areas (Examination Category E-C), and remains in IWE-3510.2, Visual Examination of Coated and Noncoated Areas (Examination Category E-A),
and IWE-3511.3, Ultrasonic Examination (Examination Category E-C).
Describe the course of action necessary if an augmented visual examination fails to meet the acceptance criteria using the 1998 Code.
TU Electric Response:
As discussed in the IWE commentary (Reference 2), the 1998 Edition of IWE reorganized IWE-3500 Acceptance Standards. The 1998 Edition of IWE-3122 1
contains provisions for acceptance by examination, acceptance by repair / replacement and acceptance by engineering evaluation for all components not meeting the acceptance standards of IWE-3500, including Examination Category E-C. Surface areas requiring augmented examination are further defined in paragraph IWE-1240 and require successive inspections in accordance with IWE-2420 (b).
r Attachment to TXX-99082 Page 7 of 9 CPSES Response to the NRC RAl's regarding Units 1 and 2 Relief Requests E-1 and L-1 NRC RAI 7.
The IWE rewrite submitted with the licensee's proposed alternative lists IWE-2310(e)(3) and (4) as criterla for detailed visual examination of (3) pressure retaining bolting and (4) moisture barriers. These criteria do not appear in the 1998 Edition. The 1998 Code appears to leave these components without suitable examination criteria. Is the licensee proposing to use the criteria [from 1992 Edition) submitted in the proposed alternative to augment this lack of information in the 1998 Edition?
YU Electric Response; i
As stated in the response to question No.1. TU Electric inten 's to use the published 1998 Edition of ASME Section XI, Subsections IWE and IWL. The 1998 Edition does not contain requirements for pressure retaining bolting and moisture barriers in paragraphs IWE-2310(e)(3) and (4). These requirements exist in the 1998 Edition Table !WE-2500-1, Examination Category E-A by reference from IWE-2310(b). Pressure retaining bolting is included in item No.
E1.10 per footnote (1)(d) and Moisture Barriers are contained in item No. E1.30.
As stated in the response to question 3, bolting will be examined to the acceptance criteria for VT-1 examinations.
NRC RAI 8.
lWE-2420(c), Successive Examinations, (92 Ed) requires areas containing flaws, areas of degradation, or repairs that were found acceptable by engineering evaluation, be reexamined during the next three inspection periods before it can be removed from the augmented examination requirements. This is consistent with the Subsection IWB-2420 requirements. The proposed alternative has reduced the observation time required to remove a suspect area from the augmented examination requirements. IWE-2420(c)(98 Ed) requires reexamination of areas containing flaws or areas of degradation, that have been accepted for continued service by engineering evaluation, during the next inspection period. If the suspect area is unchanged during the next period examination, the area no longer requires augmented examination. The licensee must submit a basis for why this reduction in the number of successive examinations provides an acceptable, or equivalent, level of quality and safety.
TU Electric Response:
As stated in the IWE commentary (Reference 2), "The requivements for reexamination of augmented examination areas has been revised to be consistent with Class 1 and 2 such that only one additional examination is required during the next inspection period before the item can be removed from an Owner's augmented examination program. The committee believed that this would be sufficient since a root cause analysis is required in addition to the repair plan.' As part of the repair plan, the Code requires a suitability of repair evaluation which includes a consideration of the repair over the plant's lifetime.
Attachm:nt to TXX-99082 Page 8 of 9 CPSES Response to the NRC RAl's regarding f,
Units 1 and 2 Relief Requests E-1 and L-1 Areas that have been evaluated and removed from the augmented examination program after successful completion of two examinations may be subject to augmented examination during successive Inservice inspection Intervals if an Owner determines that conditions which could cause degradation in these areas still exist."
The ability to designate an area as augmented during successive examinations ensures that the area is monitored for as long as necessary. Additionally the type of flaws that are anticipated to be detected during containment examinations will not be similar to those detected during piping examinations.
That is crack like flaws that can be evaluated with fracture mechanics methods i
for piping are unlikely to be detected nor evaluated by fracture mechanics for containment examinations.
NRC RAI 9.
Examination Category E-D, Pressure Retaining Dissimilar Metal Welds, has been removed from Table IWB 2500-1. The 1998 Edition, Examination Category E-A, does not specifically address dissimilar metal welds. 50% of the total number of dissimilar metal welds associated with the containment system were to receive a surface examination. What is the extent of dissimilar metal welds in the Comanche Peak containment structures?
How does a general visual examination provide the same acceptable level of quality and safety as a surface examination?
TU Electric Rwponse:
The NRC Rulemaking (Page 41308 of Reference 1) states in part, "makes the examinations of Subsection IWE, Examination Category E-B (pressure retaining welds) and Subsection IWE, Examination Category E-F (pressure retaining dissimilar metal welds) optional. The NRC staff concludes that requiring these examinations is not appropriate. There it no evidence of problems associated with welds of this type under the given ooerating conditions."
Pressure-retaining dissimilar metal welds have been removed as a separate Examination Category in the 1998 Edition. A requirement for a general visual examination of pressure boundary welds is still contained in the 1998 Edition of Table IWE 2500-1, footnote 1 for item No. E1.10 Pressure Retaining Boundary.
Therefore the resulting changc is consistent with the NRC Rulemaking (Reference 1) that removes the emphasis from weld based examinations.
There are some dissimilar weld meta!s at Comanche Peak. However, for the reasons stated above, the 1998 Edition examination requirements provide an acceptable level of quality and safety.
Attachment ts TXX-99082 Page 9 of 9 CPSES Response to the NRC RAl's regarding j
Units 1 and 2 Relief Requests E-1 and L-1 NRC RAI 10. Examination Category E-G, Pressure Retaining Bolting, has been removed from Table IWE 2500-1. The 1992 Edition required VT-1 visual of bolting when a connection was disassembled. The 1998 Edition requires a general visual, performed in place, with no requirement when the Joint is disassembled. The licensee should provide an argument for why not performing a VT-1 visual examination of the bolting, when disassembiad, provides an acceptable (equivalent) level of quality and safety.
TU Electric Response:
)
Prossure-retaining bolting has been removed as a separate Examination Category in the 1998 Edition. A requirement for a general visual examination of pressure boundary botting is still contained in the 1998 Edition of Table IWE 2500-1, footnote 1 for item No. E1.10 Pressure Retaining Boundary.
The philosophy for examining bolting in place is consistent with the requirements for ASME Code Class 1,2 and 3 bolting.
As stated in the IWE commentary (Reference 2), " Exposed surfaces of pressure-retaining bolting are to receive a general visual examination during each inspection period. Any evidence of degradation which could affect the containment leak-tight or structural integrity must be evaluated. Bolting which is subject to degradation shall also require augmented examination in accordance with IWE-2420(b) and (c). Bolting need not be disassembled to perform these examinations, and only those portions of bolting that are exposed to environmental conditions require examination. Local pressure tests of bolted j
and gasketed joints performed in accordance with 10CFR50, Appendix J j
demonstrate containment leak-tight integrity. These visual examinations are performed to evaluate any inservice environmental effects that could adversely affect the performance of bolted and gasketed joints on containment penetrations which have been adequately assembled and tested.
Bolting has been included in Subsection IWE because pressure-retaining bolting is not routinely addressed under current license programs (e.g.,10CFR50, Appendix B) unless the connection was disassembled for some reason. The committee believes it prudent to perform a visual examination for evidence of boric acid crystals, for example."
j References 1.
Federal Register: August 8,1996, Volume 61, Number 154, Rules and Regulations, Pages 41303-41312, Codes and Standards for Nuclear Power Plants; Subsection IWE and Subsection IWL, Final Rule.
2.
ASME Code Section XI, Subsection IWE Commentary (This is maintained by and available through the ASME organization).