ML20195G298
| ML20195G298 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 11/11/1998 |
| From: | Terry C, Walker R TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| GL-98-04, GL-98-4, TXX-98249, NUDOCS 9811200252 | |
| Download: ML20195G298 (9) | |
Text
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l FE LOG # TXX-98249 File # 10035 l
r r Ref. # 10CFR50.54(f)
GL 90'0A 1UELECTRIC l
- c. uwe nrry November 11,1998 Senior Vice President
& PrincipalNuclear Officer U. S. Nuclear Regulatory Commission Attn.: Document Control Desk l Washington, D.C. 20555-0001 l
SUBJECT:
COMANCHE PEAK STEAM ELECTRIC STATION (CPSES) l DOCKET NOS. 50-445 AND 50-446 RESPONSE TO GENERIC LETTER 98-04," POTENTIAL FOR DEGRADATION OF THE EMERGENCY CORE COOLING SYSTEM AND THE CONTAINMENT SPRAY SYSTEM AFTER A LOSS-OF-COOLANT ACCIDENT BECAUSE OF CONSTRUCTION AND PROTECTIVE COATING DEFICIENCIES AND FOREIGN MATERIAL IN CONTAINMENT" REF: 1) Generic Letter 98-04," Potential for Degradation of the Emergency Core Cooling System and the Containment Spray System after a Loss-of- )
coolant Accident Because of Construction and Protective Coating '
Deficiencies and Foreign Material in Containment",
dated July 14,1998 On July 14,1998, the Nuclear Regulatory Commission issued Generic Letter 98-04 (Reference 1). This letter provides TU Electric's response to the subject Generic Letter in Attachment 2.
This cornmunication contains no new commitments regarding CPSES Units 1 and 2.
If you have any questions, please contact Carl Corbin at (254) 897-0121.
Sincerely,
$.h.
C. L. Terry 1
w OY' 9811200252 981111 Ro'ger--. Walker PDR ADOCK 05000445 Regulatory Affairs Manager C l p P DR.
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CBC/cbc Attachments ho cc: Mr. E. W. Merschoff, Region IV Mr. J.1. Tapia, Region IV Mr. T. J. Polich, NRR Resident inspectors, CPSES i
COMANCiiE PEAK STEAM ELECTRIC STATION
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-- v i P.O.B m 1002 Glen Rose. Texas 76043-1002
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l l Attachment 1 to TXX-98249 Page 1.of 1 -
l UNITED STATES OF AMERICA l NUCLEAR REGULATORY COMMISSION l
in the Matter of )
)
Texas Utilities Electric Company ) Docket Nos. 50-445 l l ) and 50-446 l l (Comanche Peak Steam Electric )
i Station, Units 1 & 2) )
AFFIDAVIT Roger D. Walker being duly sworn, hereby deposes and says that he is the Regulatory l Affairs Manager for Comanche Peak Steam Electric Station of TU Electric, the licensee herein; that he is duly authorized to sign and file with the Nuclear Regulatory Commission this Response to Generic Letter 98-04," Potential for Degradation of the '
Emergency Core Cooling System and the Containment Spray System after a Loss-of- i coolant Accident Because of Construction and Protective Coating Deficiencies and l Foreign Materialin Containment".; that he is familiar with the content thereof; and that i i the matters set forth therein are true and correct to the best of his knowledge, information and belief.
W h*
RogeH). Walker Regulatory Affairs Manager STATE OF TEXAS )
COUNTY OF 6csywevdk )
Subscribed and sworn to before me, on this day of btUfbr.1998.
Mi k W bC w- $ Notdjy Public
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} Gato R. P0ch JOSp0040 I
- Natuy Public.Stataof Tans y My Comm.Egtres 03/16/02 >
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l Attachm:nt 2 to TXX-98249 Page 1 of 7 l NRC GL 98-04 requests information from licensee's regarding whether protective coatings inside the containment comply and conform with the current licensing basis for their facilities and whether the regulatory requirements pursuant to 10 CFR 50.46 are being met. GL 98-04 clearly defines the scope of the generic letter as being specific to Service Level 1 protective coatings inside containment.
There are no Service Level 1 protective coatings within the Containment Buildings at l
CPSES as defined by GL 98-04. Protective coatings at CPSES were de-classified to non safety-related in March 1985. NUREG 0797," Safety Evaluation Report Related to the Operation of Comanche Peak Steam Electric Station, Units 1 and 2", Supplement No. 9 provides the basis for de-classification of CPSES Containment Building protective coatings.
With respect to the exception to the Service Level 1 designation of Containment Building protective coatings provided above, TU Electric provides the following responses to the information requested per GL 98-04. Unless otherwise noted, the responses provided applies for both CPSES Units 1 and 2.
NRC GL 98-04. Reauired Information. Item 1 As a result of NRC findings in these areas and due to the importance of ensuring system functionality, within 120 days of the date of this generic letter, addressees are required to submit a written response that includes the following information:
(1) A summary of the plant-specific program or programs implemented to ensure that Service Level 1 protective coatings used inside the containment are procured, applied, and maintained in compliance with applicable regulatory requirements and the plant specific licensing basis for the facility. Include a discussion of how the plant-specific program meets the applicable criteria of 10 CFR Part 50, Appendix B, as well as Information regarding any applicable standards, plant-specific procedures, or other guidance used for: (a) controlling the procurement of coatings and paints used at the facility,(b) the qualification testing of protective coatings, and (c ) surface preparation, application, surveillance and maintenance activities for protective coatings.
Maintenance activities involve reworking degraded coatings, removing degraded coatings to sound coatings, correctly preparing the surfaces, applying new coatings, and verifying the quality of the coatings.
TU Electric Resoonse to item 1 (1)(a) Controllina the orocurement of coatings and oaints used at the facility TU Electric applies administrative and augmented quality controls on the procurement of Containment Building coating materials that provide adequate assurances that the materials purchased comply with CPSES licensing basis and regulatory commitments. Specifically, TU Electric has committed to using Containment Building protective coatings materials that are Design Basis Accident (DBA) qualified in accordance with ANSI N101.2-1972. Protective coatings that are used in radiation areas (inclusive of Containment) are selected for use based on the material test data results obtained from ANSI N512-1974 testing.
i l
Attachm:nt 2 to TXX-98249 1 Page 2 of 7
, TU Electric Engineering procedures delineate requirements for the procurement and control of Containment Building coating materials. Receipt inspection of Containment Building coating materials is performed by a qualified Coatings Engineer. Receipt inspection includes verification of the materials certificate of conformance to applicable ANSI standards by the coating manufacturer's quality assurance department.
CPSES Engineering and Maintenance coating procedures provide detailed instructions based on the coating manufacturers recommendations for the handling and storage of Containment Building coating materials once received.
l (1)(b) aualification testing of orotective coatings 1
- Containment Building protective coatings are tested in accordance with ANSI N101.2 and ANSI N512. ANSI N101.2 test results are evaluated by TU Electric Engineering using the acceptance criteria specified within the standard, TU Electric Engineering also assess test parameters used in ANSI N101.2 testing for conformance to CPSES specific DESIGN BASIS ACCIDENT (DBA) environmental conditions. ANSI N512 test results for coating materials are reviewed by TU Electric Engineering to assess suitability of the coating material for the given application.
(1)(c) surface orecaration. aoolication. surveillance and maintenance activities for orotective coatinos.
NUREG 0797, SSER No. 9 provides the licensing-basis for CPSES Containment Building protective coatings. In Appendix L to SSER No. 9, the staff relieved TU Electric from it's prior commitment to meet the positions of Reg. Guide 1.54 based on a detailed review of TU Electric's analysis on l Containment coatings. Although the standards of 10 CFR 50, Appendix B no
- longer applied to CPSES coatings, TU Electric was directed by the staff to propose a pre- and post-operational coatings program consistent with the guidelines prescribed in Appendix L of SSER No. 9.
NUREG 0797, SSER No. 21, provides the staff's acceptance of TU Electric's proposed coatings program for CPSES. The staff concluded that the CPSES coatings program met the guidelines of SSER No. 9, Appendix L which included the following essential elements:
. qualification and training of inspection personnel
- . inspection and test procedures that specify operating methods for each inspection and test, inspection equipment, the frequency of testing and inspection, the acceptance criteria for each inspection and test, and record keeping to document each inspection and test
. verification of storage and handling of protective coatings
. calibration of measuring and test equipment
. reporting, disposition, and tracking of coating degradation and deficiencies
. completion, issuance, and control of documentation 4
l Attachm:nt 2 to TXX-98249 Page 3 of 7
. maintenance and control of the Coatings Exempt Log
. methods and criteria for operational surveillance of Containment Building coatings repair procedures that ensure good workmanship and that are to be employed consistent with ALARA guidelines for radiation exposure criteria to achieve quality coating material and workmanship; namely the use of coating materials that meet the DESIGN BASIS ACCIDENT (DBA) conditions TU Electric developed the CPSES coatings program using industry recognized standards and good painting practices. These standards and practices are consistent with those recommended for use in EPRI TR-109937," Guideline on Nuclear Safety-Related Coatings" and are also endorsed by ASTM D-5163," Standard Guide for Establishing Procedures to i
Monitor the Performance of Safety Related Coatings in an Operating Nuclear l Power Plant". l The CPSES " Maintenance Coatings Program"is implemented through several site procedures that include Station Administrative Procedures, Engineering Procedures and Mechanical Maintenance (coatings / paint) Procedures.
Containment Building coatings are included within the scope of the CPSES Maintenance Coatings Program.
Containment Building coating activities consist of three primary processes:
(1) monitoring { surveillance} of applied coatings, (2) evaluation and repair of coating deficiencies identified as a result of monitoring, and (3) coating applications in support of plant modifications. The following provides an overview of these three processes:
(1) Monitorina Monitoring of Containment Building coatings is conducted at a minimum, once each fuel cycle. Monitoring primarily involves conducting a general visual examination of all assessable coated surfaces within the Containment Building. Examinations are conducted by qualified Coating Verification Engineer (s). Detailed instructions on conducting coating examinations, including deficiency reporting criteria and documentation requirements are delineated in an Engineering Procedure.
Examples of coating deficiencies that are to be identified during the monitoring process include, but are not limited to the following: uncoated (bare substrate) areas, areas exhibiting loss of adhesion (peeling / flaking /
etc.), areas exhibiting blistering, scorched or burnt coatings, pinpoint rusting, general rust through or corrosion nodules, other coating defects (e.g., low film thickness, unspecified coatings, softening of coatings, excessive mechanical damage, checking, cracking, etc.)
Identified coating deficiencies are categorized by deficiency type, quantified by size and / or relative frequency of deficient condition using industry standards, and are individually mapped for future reference. In addition, information relevant to accessibility of the deficient condition and comments l that may assist in work planning (e.g., ALARA concerns, obstructions, etc.)
are provided in the reporting process.
Attachment 2 to TXX-98249 Page 4 of 7
, Consistent with CPSES licensing commitments, emphasis is placed on items and areas of specific interest which are to be examined in detail. Examples of items / areas that require detailed examination include: samples of coatings from the Protective Coatings Exempt Log, areas adjacent to the Containment Building Recirculating Sumps, and areas in Higher Radiation Zones accessible for raoid verification.
Coating deficiencies are evaluated by the Protective Coatings Coordinator (PCC). The PCC utilizes the following considerations when evaluating and providing dispositions for each identified coating deficiency:
- ALARA Program (consults with Radiation Protection Group)
- Type and size of deficiency e impact on plant equipment and operation
- Conditions contributing to coating failure e Repair method and time required to complete repair e Location and difficulty of repairing deficiency
- Potential effect of leaving condition as-is e Notification of significant coating degradation to management The_PCC summarizes results of the evaluation process and initiates and prioritizes work requests to ensure that appropriate corrective actions are implemented based on the severity / significance for each identified coating deficiency.
(2) Reoair of Coatino Deficiencies Containment Building coating deficiencies are repaired by qualified coating applicators. Coating repair work is performed in accordance with a coatings procedure that is reviewed and approved by the Protective Coatings Coordinator. The coatings procedure utilizes coating manufacturer's technical instructions, industry recognized standards and good painting practices that provide reasonable assurance that the coatings will maintain their integrity without separating from the surfaces to which they have been applied.
Verification of primary attributes associated with in-process coating work is mandatory for all Containment Building applications by a qualified applicator.
Coating Verification Engineer (s) conduct random surveillances of in-process coating activities to ensure procedural requirements are being meet.
Additionally, the PCC establishes mandatory Hold Points for coating work of significance or work that otherwise warrants independent verification.
[3) Plant Modifications Containment Building coating work that is conducted in support of plant modifications utilizes the same procedures and processes described abova for Containment coating deficiency repairs. An Engineering procedure provides administrative controls that ensure items that are to be installed in
Attachm:nt 2 to TXX-98249 j Page 5 of 7 the. Containment Building are appropriately reviewed by the Protective 4
Coatings Coordinator to assure qualified coating materials and procedures are specified in the modification process.
NRC GL 98 04. Reouired Information. Item (2) 4 (2) Information demonstrating compliance with item (1) or item (11):
(i) For plants with licensing basis requirements for tracking the amount of unquallfled coatings inside the containment and for
] assessing the impact of potential coating debris on the operation of safety-related SSCs during a postulated DB LOCA, the following Information shall be provided to demonstrate compilance:
(a) The date and findings of the last assessment of coatings, and the planned date of the next assessment of coatings.
(b) The limit for the amount of unquallfled protective coatings allowed in the containment and how this limit is determined.
Discuss any conservatism in the method used to determine limit.
4
- (c ) If a commercial grade dedication program is used at your
- facility for dedicating commercial grade coatings for Service Level 1 applications inside the containment, discuss how the
- program adequately qualifies such a coating for Service Level 1 service. Identify which standards or other guidance are ,
currently being used to dedicate containment coatings at your '
facility; or I
(ii) For plants without the above ll:ensing basis requirements, information shall be provided to demonstrate compliance with the !
requirements of 10 CFR50.46b(5),"Long term cooling" and the i functional capability of the safety related CCS as set forth in your l licensing basis, if a licensee can demonstrate this compliance !
without quantifying the amount of unquallfled coatings, this is acceptable. The following information shall be provided: )
(a) If commercial grade coatings are being used at your facility for Service Level 1 applications, and such coatings are not dedicated or controlled under your Appendix B Quality Assurance Program, provide the regulatory and safety basis ,
for not controlling these coatings in accordance with such a !
program. Additionally, explain why the facility's licencing i basis does not require such a program.
TU Electric Resoonse to item 2 Relevant Licensino-Basis Information in SSER No. 9, the NRC staff concluded that CPSES Containment Building coatings need not meet the standards of 10 CFR 50, Appendix B. While relaxation from meeting the full burden of Appendix B standards was granted, '
the NRC staff did impose other comparable quality requirements on TU Electric in Appendix L of SSER No. 9. These quality requirements include:
use of Design Basis Accident (DBA) qualified coating materials, use of
Attachm:nt 2 to TXX-98249 Page 6 of 7 qualified application and inspection personnel, quality verification of coating work, and development of comprehensive coating procedures that ensure good workmanship. The staff reviewed and approved TU Electric's proposed coatings program containing these quality elements in Appendix L of SSER No.21.
Relevant actions required of TU Electric in Appendix M of SSER No. 9 included updating and maintaining the Coatings Exempt Log (CEL). The staff concluded in Appendix M that, "Although all coatings are now considered not safety related, the CEL shall still be maintained to separately identify allitems which did not meet the requirements in effect at the time the coating work was performed. This log will be used in planning future inspections of coatings consistent with the guidelines of Appendix L."
Based on the NRC endorsement of the CPSES's coatings program, TU Electric considers protective coatings that are applied in accordance with the approved program " qualified" for CPSES. Conversely, coatings that do not meet the requirements of, or have not been applied in accordance with this program are considered " unqualified". Containment Building unqualified coatings are tracked on the Coatings Exempt Log.
(2)(i)(a) A comprehensive visual examination of all assessable coated surfaces inside the Unit 1 Containment (approximately 610,000 square feet) was conducted between 03/21/98 and 04/18/98 during refueling outage 1RF06. 165 new coating deficiencies encompassing 407 square feet of surface area were identified during this assessment. Examples of the type of coating deficiencies identified include: uncoated / rusted substrate, loss of adhesion, blistering, checking / cracking, burnt coatings, and areas of mechanical damage. 157 of these deficiencies (394.5 sq. ft.) were dispositioned to be repaired. 192 previously identified deficiencies that were being monitored were re-evaluated and dispositioned to be repaired during this assessment period.
The next planned assessment of Containment Building coatings for Unit 1 is !
scheduled for refueling outage 1RF07 (Fall 1999).
A comprehensive visual examination of all assessable coated surfaces inside i the Unit 2 Containment (approximately 610,000 square feet) was conducted ;
between 10/25/97 and 11/28/97 during refueling outage 2RF03. 44 new l coating deficiencies encompassing 452 square feet of surface area were '
identified during this assessment. 2 of the identified deficiencies (mechanical damage related) accounted for 317 square feet of this 452 sq. ft. total. '
Examples of the type of coating deficiencies identified include: )
uncoated / rusted substrate, loss of adhesion, blistering, mudcracking, burnt '
coatings, and areas of mechanical damage. 40 of these deficiencies (450 sq.
ft.) were dispositioned to be repaired.121 previously identified deficiencies that were being monitored were re-evaluated and dispositioned to be repaired during this assessment period.
The next planned assessment of Containment Building coatings for Unit 2 is scheduled for refueling outage 2RF04 (Spring 1999).
I i
. l Attachm:nt 2 to TXX-98249 Page 7 of 7 (2)(i)(b) Appendix L of SER No. O provides results of the NRR detailed review of TU Electric's analysis regarding Containment Building coatings. The NRR staff 4 concluded,"a total failure of protective coatings inside the Containment Building would not adversely affect the performance of post-accident fluid systems. Accordingly, any deficiencies which might result in coating failures would not result in or contribute to causing, or increasing the consequences of, any design basis accident; for this reason, it is not necessarv that coatinos be cualified." Based upon this conclusion, TU Electric submits,"all protective coatings inside the Containment Building may be unqualified" The following conservatism were noted by the NRC office of Nuclear Reactor Regulation in their detailed review of TU Electric's Containment Building coatings analysis:
As a worst case, TU Electric assumed that all coating failed completely.
TU Electric assumed a more conservative manner for coating failure mode (flaking) from the standpoint of potential sump screen blockage.
TU Electric's assumption that all coatings inside the Containment Building will fail and generate debris is conservative.
TU Electric conservatively assumed 1/8-inch particles in the sump blockage analysis, since these would lead to screen blockage, and because larger debris particles are more difficult to transport.
TU Electric conservatively assumed that the paint particles would be transported, accumulating at the base of the screens with a 45-degree angle of repose for blockage estimates.
Threshold water velocity of 0.27 ft/sec for 1/8-inch paint particles calculated from far-field debris transport model is conservative compared with the velocity considered necessary to suspend and transport coal slurries of similar particle size and density.
TU Electric's transport model for the region near the sump is also conservative in considering the terminal velocity of paint chips to be 0.16 ft/sec for the tumbling chips.
Methodology utilized for calculating particle (fine debris) transport was found to be conservative.
The staff found TU Electric's estimates of fine debris volume, and of the concentrations of abrasive and non abrasive debris concentrations in the circulating coolant acceptably conservative.
(2)(i)(c) Commercial-grade dedication is not used for CPSES Containment Building protective coatings. CPSES Containment Building protective coating materials are qualified in accordance with ANSI N101.2 and N512, and have flame spread and smoke density ratings equal to, or less than 25 when tested per ASTM E-84.
(2)(li)(a) Not applicable, see response to Item (2)(i).
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