ML20236Q226
| ML20236Q226 | |
| Person / Time | |
|---|---|
| Issue date: | 06/11/1998 |
| From: | Callan L NRC OFFICE OF THE EXECUTIVE DIRECTOR FOR OPERATIONS (EDO) |
| To: | |
| Shared Package | |
| ML20236Q222 | List: |
| References | |
| SECY-91-172-C, SECY-98-136, SECY-98-136-01, SECY-98-136-1, SECY-98-136-R, NUDOCS 9807200083 | |
| Download: ML20236Q226 (9) | |
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j POLICY ISSUE (Information)
June 11.1998 SECY-98-136 EDB:
The Commissioners FROM L. Joseph Callan Executive Director for Operations
SUBJECT:
PROPOSED NRC GENERIC LETTER TITLED ' POTENTIAL FOR DEGRADATION OF THE EMERGENCY CORE COOLING SYSTEM AND THE CONTAINMENT SPRAY SYSTEM AFTER A LOSS-OF-COOL. ANT ACCIDENT BECAUSE OF CONSTRUCTION AND PROTECTIVE COATING DEFICIENCIES AND FOREIGN MATERIAL IN CONTAINMENT
- PURPOSE:
Tc inform the Commission, in accordance with the guidance in the December 20,1991, l
memorandum from Samuel J. Chilk to James M. Taylor regarding SECY-91-172, " Regulatory impact Survey Report-Final," of the staffs intent to issue the attached generic letter. The l
purpose of the generic letter is to: (1) notify addressees about problems with the material condition of Service Level 1 protective coatings inside containment, (2) require cubmission of I
information necessary to verify that licensees are complying with their plant-specific licensing bases to ensure the operability of emergency core cooling systems (ECCSs) and safety-related systems, structures, and components (SSCs), and (3) inform addressees that enforcement action will be pursued if debris is found in containment.
A copy of the proposed generic letter is attached.
CONTACTS: James A. Davis, NRR NOTE: TO BE MADE PUBLICLY AVAILABLE (301)415-2713 IN 5 WORKING DAYS FROM THE DATE OF IRIS PAPER Richard,'A. Lobel, NRR (301)415-2865
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The Commissioners -
DISCUSSION.
NRC regulations in 10 CFR 50.46 require that licensees design their ECCSs to provide long-term cooling capability so that the core temperature can be maintained at an acceptably low valde and decay heat can be removed for the extended period required by the long-lived radioactivity remaining in the core. The ECCSs take suction from suppression pools or the emergency sumps in containment. Some addressees may credit containment spray systems (CSSs) in the licensing basis for radioactive-source-term and pressure reduction. These CSSs may also take suction from the suppression pools or emergency sumps.
Foreign ma*.orials, degraded costings inside the containment that detach from their substrate, and ECCS components not consistent with their design basis, along with LOCA-generated debris, are potential common-cause failure mechanisms which may clog suction strainers, sump screens, filters, nozzles, and small-clearance flow paths in the ECCS and safety-related CSS and thereby interfeia with the long-term cooling function.
The NRC staff is not establishing a new position in this generic letter. The generic letter only requires information from licensees under the provisions of Section 182a of the Atomic Energy Act of 1954, as amended, and 10 CFR 50.54(f).
A notice of opportunity for public comment was published in the Federa/ Register. Comments were received from one industry organization and four licensees. The comments focused on:
(1) whether the generic letter imposes a backfit on older plants, (2) clarifying that coatings outside of containment should be excluded from the generic letter, (3) whether coatings should be covered by the maintenance rule, (4) the length of the period for licensees to respond to the generic letter, and (5) editorial comments. De staff has evaluated these comments and made appropriate changes to the generic lettes. Copies of the comment letters that were received are available in the Public Document Room (PDR). A copy of the staff's evaluation of the public comments is available in the NRC File Center and will be made available in the PDR after the generic letter is issued.
COORDINATION The staff presented the proposed generic letter to the Committee to Review Generic Requirements on January 30,1998, and received the Committee's Endorsement of February 5, 1998. The staff presented the proposed generic letter to the Advisory Committee on Reactor Safeguards on April 22,1997, which indicated its support for the proposed generic letter.
.e The Commissioners.
The Office of Enforcement reviewed this generic letter and has no objection to it. The OfHce of the General Counsel reviewed this generic letter and has no legal objection to it.
The staff intends to issue this generic letter 5 working days after the date of this information
, Paper.
I oseph Callan ecutive Direct r for Operations
Attachment:
Proposed NRC Generic Letter Titled " 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" DISTRIBUTION:
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June 27,1997 Mr. David L.- Meyer, Chief Rules Revie v and Directives Branch U.S. Nuclear Regulatory Conunission Mail Stop T-6D-69 Washington, DC 20555-0001
SUBJECT:
Proposed Generic Communication: 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 DeSciencies and Foreign Material in the Containment (62 Fed. Reg. 26331)
Dear Mr. Meyer:
Enclosed are comments submitted on behalf of the nuclear power industry by the Nuclear Energy Institute (NEI)1 These comments are in response to the May 13,1997 Federal Register " Notice of opportunity for public comment" concerning the subject proposed generic letter.
We appreciate the opportunity to comment on this proposed generic letter.
Please direct any questions on our comments to John Butler at (202) 739-8108.
Sincerely, David J. Modeen JCB/tmc Enclosure l
1 NEI is the organization responsible for establishing unified nuclear industry policy on matters affecting the nuclear energy industry, including regulatory aspects of generic operational and technical issues. NEI l
members include all utilities licensed to operate commercial nuclear power plants in the United States, nuclear plant designers, major architeet/ engineering firms, fuel fabrication facilities, materials licensees, and other organizations and individuals involved in the nuclear energy industry.
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Enclosure Industry Comments on Proposed Generic Communication:
Potential for Degradation of the Emergency Core Cooling System and the Containment Spray System After a Loss-of Coolant Accident l
Because of Construction and Protective Coating Deficiencies and
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Foreign Materialin the Containment l
A) Separate Generic Communications Would Provide Better Focus on IndividualIssues The proposed generic letter identifies three areas of concern:
- 1) foreign materialin containment,
- 2) design deficiencies and material condition deficiencies of ECCS structures, systems and components inside containment, and
- 3) problems with protective coatings inside containment.
With respect to the first two areas of concern, the proposed generic letter summarizes previous generir: communications and notes NRC staff expectation that licensees should have already considered possible actions to address these concerns. For the third area of cc,ncern the proposed generic letter alerts licensees to problems associated with the material condition of protective coatings inside containment and requests information to evaluate licensee programs for protective coatings.
The proposed generic letter covers a wide range of conditions which have the potential for degradation of containment recirculation capability following a Loss of Coolant Accident. In order to provide a greater focus on the requested licensee actions, we recommend the protective coating portion of the genui:
communication be separated from the remaining two areas of concern. Because the NRC is not requesting licensees to supply information pertaining to the first two issues, they are more appropriately addressed in an NRC Information Notice while the third issue remains the focus of the proposed generic letter.
B) No Single Coating Program For many licensees the control of safety-related coatings is covered in multiple plant procedures and other processes; including procurement, training, maintenance, engineering, etc. There is typically no single " coating" program.
Therefore, responses to the request for summary description of the " plant-specific program" for protective coatings willinvolve a description of applicable portions of multiple plant processes and procedures. The proposed generic letter
should be modified to acknowledge the existence of multiple plant-specific activities addressing protective coatings and the acceptability of a response which summarizes the applicable portions of plant procedures and processes which address protective coatings.
C) Localized Failures Do Not Indicate Complete Failure The proposed generic letter states that qualified coatings are.canable of adhering to their substrate during a Design Basis LOCA in order to minimize the amount which can reach the emergency sump screen or suction strainers and reduce the flow by blocking the flow area. While we agree with the statement, it is important to note that instances oflocalized coating failures do not mean complete failure of the coating system and,in ofitself, does not indicate that the containment recirculation systems were challenged. It is important that licensees have adequate processes in place to detect and remedy instances oflocalized failure before they progress to a point which could challenge proper operation of the containment recirculation systems.
D) Applicability of Codes and Standards The application of coatings requires atbntion to detail. The guidance of ANSI, ASTM or other industry standards is very helpful. However, strict adherence to j
the existing coating application standards withoutjudgment and interpretation is expensive and does not necessarily achieve the desired goal of tough j
protective coatings. In the discussion provided in the FederalRegister notice, the NRC staff acknowledges that Regulatory Guide 1.54," Quality Assurance Requirements for Protective Coatings Applied to Water-Cooled Nuclear Power Plants," references outdated documents. NRC staff must exercise judgment when evaluating the acceptability of any given licensee's coatings activities relative to these standards.
E) General Comment The proposed generic letter uses the ternis " Class I" and " Class II" coatings.
These terms are not universally used by the industry to define coatings. The use of coatings terms as defined in ANSI N101.2 and ANSI N101.4 is recommended. These terms are listed below:
Service Level 1 Coating - A coating used on any exposed surface area within the primary containment facility.
Service Level 2 Coating - A coating used on any exposed surface area located outside of containment but subject to radiation and decontamination.
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Service Level 3 Coating - A coating used on any exposed surface a[ea located outside of containment whose failure could adversely effect normal plant operation, or orderly and safe plant shut-dowm.
Clarification is also needed as to the scope of the information requested by the proposed generic letter. Specifically, does the requested information cover coatings inside containment only or all safety-related coatings?
In the third paragraph of the Protective Coatines section, the following sentence should be added: "Once in contact with sump screens or suction strainers, coating chips may impact the net positive suction head (NPSH) available to the ECC& CSS pump." This sentence assists in the explanation of the potential impact of coatings on pump performance.
The second paragraph of Appendix C lists latax and polyurethane as coatings used within the drywell and wetwell of BWRs and containments of PWRs. Both of these materials have not beci den _onstrated to meet Design Basis Accident or radiation requiremmts. If they have been used, they should be listed as unqualified. To avr
' inadvertently encouraging their use, the NRC staff should ensure that the litt, clearly denotes the lack of qualification.
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June 27,1997 Es U. S. Nuclear Regulatory Commission Chief, Rules Review and Direct;ves Branch Office of Administration Mail Stop T6-D59 Washington, DC 20555-0001
Subject:
Comments on the Proposed Generic Letter; 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 Materialin the Containment CNRO-97/00015 Entergy Operations, Inc. appreciates the opportunity to comment on the subject proposed Generic Letter. Our comments are provided below.
- 1. General Comment:
The proposed Generic Letter identifies three areas of concern:
Foreign materialin containment Design deficiencies and material condition deficiencies of ECCS structures, systems, and componants inside containment Problems with protective coatings inside containment NRC is requesting information pertaining to protective coatings, only.
Presented in the proposed format, particularly when reference is made to l
inspections and aggressive enforcement, it appears the first two issues may overshadow the protective coatings issue, it may be of greater benefit to NRC and licensees to separate the first two issues from the third in order to provide proper focus to each. Because NRC is not reQJesting information 1
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L Comments on Propos:d GL Regarding Prot:ctivo Conting D ficienciss Juns 27,1997 CNRO-97/00015 Page 2 of 5 pertaining to the first two issues, they may be presented in an Information Notice discussing their relationship to protective coatings while the third issue remains in the Generic Letter.
- 2. Protective Coatings section, third paragraph:
The following sentence should be added: "Once in contact with sump screens or suction strainers, coating chips may impact the net positive suction head (NPSH) available to the ECCS/ CSS pump." This sentence explains the potential impact of the coatings on pump performance.
- 3. Discussion section, eighth paragraph:
The proposed Generic Letter makes the following statement: "To the extent that protective coatings meet these scoping criteria (sic), they are within the scope of the maintenance rule."
NRC should recognize that coatings may not be included under the o
Maintenance Rule if they do not fall into one of the categories specified M 10CFR50.65.
- 4. Discussion section, twelfth paragraph:
The proposed Generic Letter makes the following statement: "The NRC will consider violations in this area as significant regulatory failures and will, accordingly consider categorizing inadequacies at least as Severity Level lli violations. The NRC will also consider the long history of generic communications on this issue as prior notice to licensees when the agency assesses civil penalties in accordance with..."
The proposed Generic Letter implies that determining violations and their associated severity levels has already been set and, therefore, NRC will not follow the criteria established in NUREG 1600 (Enforcement Policy). This policy for any inadequacy (minor or self-identified) could lead licensees to be less than vigorous in evaluating their protective coatings. NRC appears to base this policy on a "long history of generic communications on this issue".
While we agree there is a long history regarding ECCS problems caused by debris and foreign material, there does not appear to be a "long history" of problems with containment coatings (7 of 54 items identified in Appendices A and B; and 4 of 20 identified in Appendix E of the proposed Generic Letter).
Comm:nts on Propossd GL Regarding Protsctiva Coating Dsficisnciss June 27,1997 e
CNRO-97/00015 Page 3 of 5
- 5. Roquired Information section, first paragraph:
The Generic Letter specifies a written response within 75 days from the date of the letter. The requested information may be contained in several plant programs. A longer time period (e.g.,120 days) would be more appropriate to allow gathering the requested information from the various program sources.
- 6. Required Information section, item (1):
Item (1) states, in part " 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 applicLble standards, plant-specific procedures or other guidance used for... (c) surface preparation, application, surveillance and maintenance activities (emphasis added) for protective coatings."
Entergy interprets " maintenance activities" as rework of identified degraded coatings. The expectations of maintenance activities should be specified in j
the Generic Letter to avoid confusion.
- 7. Appcndix C, item (1):
Item (1) states, in part: " Class l Service Applications, which are applications of coatings or paints to SSCs that are essential to prevent or mitigate the consequences of postulated accidents."
This definition is inconsistent with the industry interpretation of Service Level I coatings. The statement implies only safety-related SSCs need to have qualified coatings. Generally, the SSC's function is not considered when determining if qualified coatings are needed. Any surface area, on safety-related or nonsafety-related equipment, from which failed paint could make its way to the strainers, should have Service Level I coatings. There are nonsafety-related components directly above the suppression pool (e.g.,
handrails). By the above definition, such components need not have qualified coatings.
- 8. Appendix C, footnote 1:
i Footnote 1 states: " Coatings applied to non-safety-related small-scale l
components inside the containment structure, such as small lighting fixtures or small non-safety-related power buses, are an exception to this statement."
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Comments on Propos:d GL Reg rding Prot:ctivo Coating D:fici:nci:s Juno 27,1997 CNRO-97/00015 Page 4 of 5 Paint on safety-related or ncnsafety-related equipment has no bearing on the equipment's ability to pedorm its function. This statement should be revised to allow any small-scale component to be exempted regardless of safety classification. Such a position would be consistent with the general industry interpretation of ANSI N101.4, Section 1.2.4.
In addition to the above comments, Entergy endorses the comments submitted to the NRC by Nuclear Energy Institute (NEI).
Again, thank you for the opportunity to provide our comments.
Sincerely, 3
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Comments on Propos::d GL Regarding Protectiva Coating D:ficienciss June 27,1997 CNRO-97/00015 Page 5 of 5 cc:
Mr. C. M. Dugger (W-3)
Mr. J. J. Hagan (GGNS)
Mr. C. R. Hutchinson (ANO)
Mr. J. R. McGaha (RBS)
Mr. J. W. Yelverton (ECH)
Mr. Jack N. Donohew, Project Manager (GGNS)
Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Mail Stop 13-H-3 Washington, DC 20555 Mr. George Kalman, Project Manager (ANO)
Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Mail Stop 13-H-3 Washington, DC 20555 Mr. Chandu P. Patel, Project Manager (W-3)
Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Mail Stop 13-H-3 Washington, DC 20555 Mr. David L. Wigginton, Project Manager (RBS)
Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Mail Stop 13-H-3 Washington, DC 20555 l
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SUBJECT:
Calvert Cliffs Nuclear Power Plant Unit Nos.1 & 2; Docket Nos. 50-317 & 50-318 Comments on Proposed Generic Letter; 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 the Containment (62FR26331, Mav 13.1997)
Baltimore Gas and Electric Company is pleased to provide comments on the subject proposed generic letter.
The proposed generic letter discusses Class I and Class 11 service applications. The above terms appear to come from ANSI N101.4. This is confusing in that the terms most commonly used in industry today are Service Level 1, Service Level 2, and Service Level 3.
Service Level I coatings are applied to surfaces within the containment. Service Level 2 coatings are applied outside of containment and are subject to radiation exposure and radionuclides contamination.
Service Level 111 coatings are normally applied to the interior surface of pipes, tanks, pools, and pressure retaining items. They are intended for immersion and other service cor.ditions outside of containment which, in the event of failure, could adversely affect the normal plant operation or orderly and safe shutdown of the plant. Clarification of this terminology prior to issuance would help in implementation of the generic letter.
The proposed generic letter states that protective coatings are applied to steel, aluminum, and galvanized surfaces. Baltimore Gas and Electric Company notes that it is not an industry practice to coat aluminum or galvanized surfaces.
Baltimore Gas and Electric Company concurs that coatings are applied within the containment to control both corrosion and radioactive contamination levels. However, coatings are not applied go ^. 31 - g;
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o Rulis Review and Directivrs Branch June 27,1997 Page 2 within the containment to protect surfaces from erosion and wear as is stated in the proposed generic letter.
We appreciate the opportunity to comment on the generic letter.
Should you have questions regarding this matter, we will be pleased to discuss them with you.
Very truly yours,
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CHC/SJR/ dim cc:
R. S. Fleishman, Esquire H. J. Miller, NRC J. E. Silberg, Esquire Resident inspector,NRC Document Control Desk,NRC R.1. McLean, DNR Director, Project Directorate I-1, NRC J. H. Walter, PSC A. W. Dromerick, NRC 1
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Nuclear Regulatory Commission Washington, D.C.
20555 Gentlemen:
NUCLEAR REGULATORY COMMISSION (NRC) - OPPORTUNITY FOR PUBLIC COMMENTS ON PROPOSED GENERIC LETTER (GL), " 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 THE CONTAINMENT" On May 13, 1997, the NRC published a proposed generic communication related to containment coatings for public comment (Federal Recister FR26331).
The comment period expires June 27, 1997.
TVA has been working with the Nuclear Energy Institute and the Nuclear Utility Coatings Council to provide industry comments.
We consider the investigation, evaluation, and documentation efforts required by the GL to be extensive.
Due to the level of effort required, the time allowed for responding to the GL should be extended to 120 days from the date of issuance.
The proposed GL should be revised to clarify that the actions and evaluations requested by the NRC pertain only to coatings inside primary containment, since these coatings have the potential to affect flow to the safety-related system pumps.
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Chief, Rules Review and Directives Branch Page 2 June 27, 1997 The proposed GL explicitly states that qualified coatings must be demonstrated to withstand environmental conditions without detaching from their substrates.
Since coating performance degrades toward the end of effective life, some degree of loss of adherence should be expected and included in the coating evaluations.
Loss-of-adherence is identified' and mitigated through inspection or testing to insure the quantities are not large_enough to affect safety-related system operation.
The proposed GL should acknowledge the potential for limited loss-of-adherence for qualified coatings.
We appreciate the opportunity to respond to the subject proposed generic communication.
Sincerely,
/
Pedro Salas Manager Licensing and Industry Affairs cc:
U.S. Nuclear Regulatory Commission ATTN:
Document Control Desk Washington, D.C.
20555
e, Chief, Rules Review and Directives Branch Page 3 June 27, 1997 EWW:LYM cc:
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RULES & C U C H June 30,1997 Mr. David L. Meyer, Chief Rules Review and Directives Branch Division of Administrative Servicer Office of Administration U.S. Nuclear Regulatory Commission Washington, DC 20555
Subject:
Comments Conceming Proposed Generic Letter
" 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 the Containment" (62FR26331, dated May 13,1997)
Dear Mr. Meyer:
This letter is being submitted in response to the NRC's request for comments conceming a proposed Generic Letter (GL) entitled
- 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 the Containment,"
which was published in the Federal Register (i.e.,62FR26331, dated May 13,1997). This proposed GL is intended to alert licensees about the problems with the material condition of protective coatings used inside containment and the fact that foreign material continues to be found hside nuclear power plant containments.
PECO Energy appreciates the opportunity to comment on this proposed GL and offers the following comments for consideration by the NRC.
l Comments 1
in Appendix C of the proposed GL, the NRC is intending to develop a maintenance I
standard for protective coatings. EPRIis currently undertaking a similar effort. If a description of a utility's coating maintenance program is to be requested by the NRC (as stipulated in the proposed GL), including information on " applicable standards, plant-specific procedures, or other guidance," PECO Energy recommends that the NRC allow time for EPRI to continue to develop the appropriate guidance / standards, and then allow l
I for a period of implementation.
The NRC should consider that the licensing basis for some older plants may not describe the amount of unqualified coatings applied inside the primary containment norits impact on Emergency Core Cooling System (ECCS) operation. Under these circumstances, an accounting and analysis of coating material would be considered a backfit and, thus, be evaluated for promulgation under 10 CFR 50.109.
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I June 30,1997 Page 2 The NRC should consider that some licensees are installing large-capacity ECCS pump suction strainers in response to NRC Bulletin 96-03,
- Potential Plugging of Emergency Core Cooling Suction Strainers by Debris in Boiling Water Reactors.' installation of force-capacity pump suction strainers will have a significant impact on the basis for a limit on unqualified coating materials, and may affect a licensee's strategy regarding coating maintenance.
Coating materials applied to components covered by the Maintenance Rule which are located outside of primary containment should be specifically excluded from the scope of this proposed GL. These types of components are not subject to Design Basis Accident (DBA) conditions and their failure would not increase the potential for post-LOCA degradation of the ECCS Therefore, PECO Energy recommends that these particular components not be included within the scope of the proposed GL.
If you have any questions, please do not hesitate to contact us.
Very truly yours, o
l G. A. Hunger, Jr.
Director-Licensing
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~'I Tennessee VaHey Authomy.1101 Market Street Chattanooga. Tennessee 37402 2801 November 12, 1997 Chief, Rules Review and Directives Branch U.S. Nuclear Regulatory Commission Washington, D.C.
20555-0001 Gentlemen:
NUCLEAR REGULATORY COMMISSION (NRC) - OPPORTUNITY FOR PUBLIC COMMENTS ON PROPOSED GENERIC LETTER (GL), " 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 THE CONTAINMENT" On May 13, 1997, NRC published a proposed generic communication related to containment coatings for public comment (Federal Reaister FR26331).
TVA provided comments by letter dated June 27, 1997.
On September 24, 1997, NRC met with industry representatives to discuss Electric Power Research Institute guidelines on protective coatings programs.
During the meeting, TVA comments were referenced and interpreted in a manner not intended by TVA.
This letter clarifies the original comments.
l During the meeting on September 24, 1997, the staff referred to the following TVA comment:
Since coating performance degrades toward the end of effective life, some degree of loss of adherence should be expected and included in the coating evaluations.
The phrase, toward the end" is a reference to localized loss of adherence such as flaking or peeling.
Our position is that all coatings (including qualified coatings) fail at the end of their effective life.
These failures are identified and mitigated at the earliest possible moment to insure the quantities are not large enough to affect plant safety-related operation.
We do not believe that adherence i
strength degrades in such a manner that adherence can be meaningfully measured and used to predict coating failure.
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November 12, 1997 The comment is an acknowledgment that engineered coatings can meet their safety function with some amount of localized failure.
The proposed GL considers coating failures in an absolute sense (i.e., coatings must be demonstrated to withstand environmental conditions without detaching from their substrates).
TVA believes that localized adherence failures should not be equated as complete failure of the coating system.
Sincerely,
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Mark Burzynski l
Manager l
Nuclear Licensing cc:
U.S. Nuclear Regulatory Commission ATTN:
Document Control Desk l
Washington, D.C.
20555-0001 l
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h CRGR REVIEW PACKAGE PROPOSED ACTION:
Issue a generic letter providing information on the potential for foreign material in the containments of boiling-water reactors (BWRs) and pressurized-water reactors (PWRs) to clog emergency core cooling system (ECCS) suction strainers and sump screens, respectively.
The generic letter also emphasizes the importance of maintaining the integrity of protective coatings located inside the containment during postulated design basis loss-of-coolant accident (DB LOCA) conditions.
Protective coatings inside containment that lose adhesion to their substrate surfaces during a postulated DB LOCA have the
)otential to clog the strainers in BWR suppression pools or
)WR sump designs. The revised generic letter also requests that addressees (1) describe their plant-specific coating program to ensure that Service Level 1 Coatings are procured. applied, and maintained in com)liance with applicable regulatory requirements and t1e specific licensing bases for their plant and (2) demonstrate compliance with their plant-specific licensing basis for tracking unqualified coatings.
Following endorsement by CRGR, the proposed generic letter will be issued to all U.S. nuclear power plants.
CATEGORY:
2 RESPONSE TO PUBLIC COMMENTS ON DRAFT GENERIC LETTER The following public comments were received by the NRC staff and are being resolved as indicated below.
E4E BG&E-1: The pro)osed generic letter discusses Class I and Class II service applications. T1e above term comes from ANSI 101.4. This is confusing because the terms most commonly used in industry today are Service Levels 1.
I 2, and 3.
l RESPONSE: The generic letter has been revised to use the Service Class 1, 2.
i and 3 classifications.
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t BG&E-2:
It is not industry practice to apply protective coating to aluminum or galvanized surfaces.
RESPONSE: While it may not be industry practice to apply protective coating to aluminum or galvanized surfaces, no N1C requirements bar the coating of I
these surfaces.
Regulatory Guide (RG) 1.54 and some ASTM standards mention aluminum and galvanized surfaces. Therefore. the reference to coatings that may oe applied to aluminum and galvanized surfaces has not been deleted.
BG&E-3: Coatings are not applied inside containment to protect surfaces from erosion and wear.
RESPONSE: Some nuclear plants apply coatings to surfaces such as floors and walls to protect the surfaces from excessive wear. The word ' erosion" is misleading and has been taken out of the letter.
IED PECO-1:
PECO recommends that the NRC allow time for EPRI to continue to develop the appropriate guidance and standards, and then allow for a period of implementation.
RESPONSE: NRC staff aembers met with EPRI on July 3. 1997 and September 24, 1997, to discuss the EPRI program. The NRC staff encourages the industry efforts, both underway and planned, which wil! provide guidanca to ensure adequate material condition of the Service Class 1 coatings ard an understanding of the behavior of coctings which risy fail under accident I
conditions. However, the EPRI and other inaustry efforts will not be l
completed until some time in the future.
In the mea.' time, euch licensee has a responsibility to ensure that the coatings in its ]lant ccMnly with its existing licensing bases. The generic letter has )een modified and states that the licensees may find the EPRI document useful when evaluating coatings.
PECO-2: The NRC should consider that the licensing basis for some oider plants may describe neither the amount of unqualified coatings applied inside containment nor its impact on ECCS operation.
Under these circumstances, an accounting and analysis of coating material would be a backfit under 10 CFR 50.109.
RESPONSE: As stated above in response to PECO-1 the staff expects licensees to ensure that their plants satisfy their existing licensing bases.
The licensee must ensure proper functioning of the ECCS and safety-related containment saray systems during accident conditions.
If the licensee can demonstrate t11s assurar:ce without quantifying the amount of unqualified paint this is acceptable. This discussion will be added to the generic letter.
PECO-3:
Installation of large capacity strainers will have a significant impact on the basis for a limit on unqualified coating materials, and m>.y affect the strategy regarding coating maintenance.
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RESPONSE
The staff agrees that large capacity strainers will have a significant effect on the basis for a limit on unqualified coating materials.
However, the BWROG Utility Requirements Guidance specifies a nominal amount of failed paint.
It is still the responsibility of each licensee, when sizing the ECCS suction strainers for a plant, to ensure that this number is applicable and bounding for that plant.
If not, a plant-specific amount of failed coatings must be included in the design.
However, this comment does not necessitate a change in the generic letter.
PECO-4: Coating materials applied to components covered by the maintenance rule which are outside the containment should be specifically excluded from the scope of the generic letter.
RESPONSE: The generic letter has been revised to make it clear that the responses to the generic letter apply only to Service Level I coatings inside containment. However, the generic letter states that licensees must ensure 1
that Service Class 2 and 3 coatings (those outside containment) must l
satisfactorily meet the requirements of their licensing basis.
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TVA i
TVA-1:
Investigation. evaluation, and documentation efforts required by the j
generic letter are extensive. Therefore, time required to respond to the j
generic letter should be extended to 120 days from the date of issuance.
RESPONSE: The generic letter has been changed as requested.
TVA-2: The proposed GL should be revised to clarify that the actions and evaluations requested by the NRC pertain only to coatings inside primary containment. since these coatings have the potential to affect flow to safety-related system pumps.
RESPONSE
See the response to PEC0-4.
TVA-3: The GL should acknowledge the potential for limited loss of adherence for qualified coatings.
Since coating performance degrades toward the end of effective life, some degree of loss of adherence should be expected and included in the coating evaluations.
Loss of adherence is identified and mitigated through inspections and testing to ensure the quantities are not large enough to affect safety-related system operation.
RESPONSE: The staff had additional correspondence with TVA to clarify the intent of this statement. What TVA intended to say was that localized areas may lose adhesion over time, resulting in loose or )eeling coating.
These localized areas with low adhesion do not indicate tlat the entire coating system is defective. The staff responded that licensees should evaluate their coating system to determine if the loss of adhesion is localized or broad-based. The generic letter has been modified accordingly.
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.l bel NEI-1: Separate generic communications would provide better focus on individual issues. Separate the protective coatings portion of the GL from those dealing with foreign material inside containment and design and material condition deficiencies. The latter two would more appropriately be handled by an Information Notice since the GL does not request any information.
RESPONSE: The two documents were originally separate and were combined into one document at the request of CRGR to make the document more comprehensive.
They will remain as one document.
NEI-2: There is typically no single " coatings" program. Safety-related coatings are covered in a variety of plant procedures. The proposed GL should be modified to acknowledge the existence of multiple plant-specific activities and the acceptability of a response which summarizes the applicable portions of plant procedures and processes which address protective coatings.
RESPONSE: The required summary of the coatings program has been changed to a required summary of the coatings program or programs.
NEI-3:
Instances of localized coating failures do not mean complete failure of the coating system and, in and of itself, does not indicate that the containment recirculation systems were challenged.
RESPONSE
The staff agrees that localized coating failures do not mean complete failure of the coating system.
However it is the oblication of the licensee to verify that the remaining Service Level 1 coat 1ngs remain quali fied.
NEI-4: NRC must exercise judgment when evaluating the acceptability of any given licensee's coatings activities relative to the industry standards.
RESPONSE: The NRC staff will take actions it deems appropriate in keeping with the NRC requirements.
NEI-5: The GL should use the terms " Service Level 1, 2, and 3" rather than
" Class I and Class II" (See BG&E-1).
RESPONSE: The staff agrees and the changes have been made.
NEI-6: Does the requested information cover only coatings inside containment only or all safety-related coatings?
RESPONSE: See the response to PEC0-4.
1 NEI-7:
In the third paragraph of the Protective Coatinos section, the following sentence should be added:
"Once in contact with the sump screens or suction strainers, coating chips may impact the net positive suction head (NPSH) available to the ECCS/ CSS pump." This sentence helps to explain the potential impact of coatings on pump performance.
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RESPONSE: This sentence has been added to the generic letter.
NEI-8: The second paragraph of Appendix C lists latex and polyurethane as coatings used within the drywell and wetwell of BWRs and containment of PWRs.
Neither of these materials has been demonstrated to meet design basis accident or radiation requirements.
If they have been used, they should be listed as unqualified. To avoid inadvertently encouraging their use, the NRC staff should ensure that the listing clearly denotes the lack of qualification.
RESPONSE
References to latex and polyurethane have been deleted from the generic letter.
Enteray Entergy-1:
It may be of greater benefit to NRC and licensees to separate the first two issues (foreign material inside containment and design and material condition deficiencies) from the third (problems with protective coatings) in order to provide proper focus to each (See NEI-1).
RESPONSE: The two documents were originally separate and were combined into one document. They will remain as one document.
Entergy-2:
In the third paragraph of the Protective Coatinas section. the following sentence should be added:
"Once in contact with the sump screens or suction strainers, coating chips may impact the net positive suction head (NPSH) available to the ECCS/ CSS pump." This sentence helps explain the potential impact of coatings on pump performance (See NEI-7).
RESPONSE: This sentence has been added to the generic letter.
Entergy-3:
NRC should recognize that coatings may D01 be included under the maintenance rule if they do not fall into one of the categories specified in 10 CFR 50.65.
RESPONSE: The NRC staff has discussed Service Level I coatings with the Maintenance Rule Section and agreement was reached that Service Level I coatings fall under the maintenance rule.
Entergy-4: GL implies that violations and their associated severity levels has already been set and, therefore. NRC will not follow the criteria established in NUREG-1600 (Enforcement Policy). This policy for any inadequacy (minor or self-identified) could lead licensees to be less vigorous in evaluating their protective coatings.
RESPONSE: The generic letter has been modified to clarify this point.
Entergy-5: There is a long history of ECCS problems caused by debris and foreign material: there does not appear to be a long history of problems with coatings.
Finally, coatings have not actually been challanged by the design basis events under consideration.
RESPONSE: There have recently been incidents involving coatings at Zion.
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l Clinton, and other plants. This has increased the awareness of coatings by the NRC staff. EPRI. ASTM and NEI.
In addition, coating problems have not always been reported to the NRC.
Entergy-6: A longer time period would be more appropriate to permit gathering the required information from various program sources (e.g.,120 days).
(See TVA-1)
RESPONSE: The generic letter has been revised to extend the response period to 120 days.
Entergy-7:
Entergy interprets " maintenance activities" (as discussed in the Reauired Information section. Item (1)) as rework of identified degraded I
The expectations of maintenance Ectivities should be specified in the GL to avoid confusion.
RESPONSE: The following sentence will be added to the generic letter:
" Maintenance activities involve reworking degraded coatings, removing degraded coatings to sound coatings, preparing the surfaces, appliying new coatings, and verifiying the coatings' quality."
Entergy-8: The definition of Service Level I coatings is inconsistent with the industry interpretation of Service Level 1 coatings.
The statement in the GL (Appendix C. Item (1)) implies that only safety-related SSCs need to have qualified coatings.
RESPONSE: This has been corrected.
Entergy-9: Footnote 1 of Appendix C states: " Coatings applied to non-safety-related small scale components inside the containment structure, such as small lighting fixtures or small non-safety-related power buses, are an exception to this statement."
Paint on safety-related or non-safety-related equipment has no bearing on the equipment's ability to perform its function.
This statement should be revised to allow any small-scale component to be exempted regardless of the safety classification.
Such a position would be consistent with the general industry interpretation of ANSI N101.4. Section 1.2.4.
RESPONSE: The footnote has been taken out of the generic letter because the reference to the footnote has been removed from the generic letter.
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