ML20012E158

Clarifies 880624 Response to NRC Generic Ltr 88-05, Boric Acid Corrosion of Carbon Steel Reactor Pressure Boundary Components in PWR Plants.

ML20012E158
Person / Time
Site:	Comanche Peak
Issue date:	03/23/1990
From:	Beck W TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC)
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
GL-88-05, GL-88-5, TXX-90110, NUDOCS 9003300144
Download: ML20012E158 (5)

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(([ 123 - Ref. # Generic Letter 88-05 filELECTRIC

" March 23, 1990

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U. S. Nuclear Regulatory Commission -!

Attn: Document' Control Desk Washington, D. C. 20555 '

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SUBJECT:

COMANCHE' PEAK STEAM ELECTRIC STATION (CF3ES)

DOCKET-NOS.150 445 1i41 50-446 -t REVIEED RESPONSE TO NRC GENERIC LETTER 88-05 BORIC ACID CORROSION OF CARBON STEEL REACTOR PRESSURE BOUNDARY COMPONENTS IN PWR PLANTS REF: TU Electric. letter TXX-88481 from Mr. William J. Cahill Jr. to U. S. NRC dated June 24, 1988 1 Gentlemen:

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.The referenced letter provided the CPSES response to the NRC Ge.-ic Letter 88-05, " Boric Acid Corrosion of Carbon Steel Reactor Pressure Boundary Components in FWR. Plants.". TU. Electric has recently re-evaluated this program L and determined.that following portions of the previous response require

'i clarification'or' change.-

' Generic Letter Item 2 L " Procedures for locating small coolant leaks (1.e.,' leakage rates at'less than technical specification limits). It issimportantlto establish the potential.

path of the leaking coolant and the reactor. pressure boundary components .it 'is likely to contact. This information.is impor+ ant in determining the interaction between the leaking coolant and reactor coolant pressure boundary L materials." .

Previous Response to Item 2 7

CPSES currently has procedures for performance of leak inspections that identify leakage rates below the technical specification limits. . Appropriate 8 CPSES Integrated Plant Operation, System Operating and Operations Department Administration procedures address actions taken during inspections for leakage '

inside and outside containment under different plant conditions. Engineering Testing procedures address the performance of surveillances for leakage for the life of the plant. Applicable Operations Testing and Station Administrative procedures are in place which identify methods that are used to control leakage and steps to be performed when identified. Applicable station personnel will also be made aware of the steps to perform when boric acid

. corrosion is found even when not inspecting for it specifically.

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,4-When leakage and its leskage path are identified and located, appropriate station personnel shall originate a work request.per CPSESfwork document-procedures to.. identify. the conditions to the' CPSES maintenance department. -

The work document procedure will-be revised to incorporate provisions to i prevent. removal of evidence of leakage prior ta performing any required  ;

engineering examinations.

L l Revised Response ta_ Item 2

' Delete the second paragraph.

Discussion:

The first paragraph of the response to Item 2 adequately addresses the Generic letter Item 2. _The_ subject of the second paragraph is addressed in the revised response to Item _3.

Generic Letter Item 3

" Methods for conducting examinations and performing engineering evaluations to establish the impact on the-reactor coolant pressure boundary when' leakage is located. This should include procedures to promptly gather the necessary' information for an engineering evaluation before the removal of evidence of leakage, such as boric ac'u crystal buildup." -

Previous ResDonce to Item 3 CPSES currently has a program (operations failure analysis program) applicable.

for examining and evaluating reactor coolant pressure boundary leaks.

Enhancements'to this program vill be made in order-to include guidelines to address boric acid corrosion.

CPSES will maintain a trending program applicable to boric acid corrosion.

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The Operations failure analysis program and the trending. program will be used

• to-determine if a= reactor coolant pressure boundary component has been subjected to boric acid corrosion. This will include documenting the examination, evaluation and corrective action for susceptible components. I Revised PasDonse to Item 3 CPSES has implemented procedures for examining and evaluating the impact of leakage or evidence of boric acid corrosion on the carbon steel reactor

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coolant pressure boundary components. These procedures include documentation, t .. examination, evaluation and corrective action requirements. Controls are in 1 '

place to ensure that the necessary information is gathered for an engineering evaluation before the removal of evidence of leakage, such as boric acid crystal buildup. .

Discussion:

This revised paragraph has incorporated the intent of sne second paragraph

.of the previous response to item 2 which is deleted above. In addition.

'TU Electric has determined that neither the trending ner the failure analysis 4

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. Pege 3 of 4 program provide the most effective method to evaluate / examine all occurrences ~I of boric acid leakage. Rather, such events are better addressed by the '

revised problem identification and evaluation processes at CPSES. These processes provide the methods for identifying and evaluating the impact.of -

boric acid M kage, corrosion and associated leakage-paths, as well as the corrective masures to assure continued integrity of the reactor coolant pressure boundary. Depending on the severity of leakage or corrosion, these processes'could lead to the performance _of root cause analysis, if appropriate. Therefore, reference to a specific boric acid failure analysis

• or trending program has been' deleted.

Generic Letter Item 4

" Corrective actions to prevent recurrences of this type of corrosion. This '

should include any modifications to be introduced in the present design or operating procedures of the plant that (a) reduce the probability of primary l coolant leaks to the locations where they may cause corrosion damage and (b) entail the. w of suitable corrosion resistant materials or the application of protective coatings / claddings."

Previous ResDonse to Item 4 ,

CPSES will review industry operating experience for boric acid corrosion prior to June 1,_1989. Boric acid corrosion affected components discovered at CPSES will be evaluated by utilizing the failure analysis program. Any approprittt design modifications that reduce corrosion will be initiated. These design  ;

modifications may consist of replacing components subject to boric acid corrosion with more corrosion-resistant parts or the application of protective coatings / claddings.

Revised Responte to Item 4 CPSES has reviewed available industry operating experience and determined that there was-no generic boric acid corrosion issues which require changes to r CPSES design. Boric acid' corrosion affected components discovered at.CPSES l will be evaluated on a case-by-case basis to determine if design modifications L or other appropriate actions are required. These design modifications may I consist of replacing components subject to boric acid corrosion with more corrosion-resistant parts or the application of protective coatings / claddings

[, and/or other design considerations which would reduce the probability of future leakage.

l' Discussion:

As. indicated above, CPSES has completed a review of boric acid corrosion industry . operating experience. No recommended modifications were identified.

The reference to a " failure analysis program" has also been removed since l'

TV Electric's approach is to identify and correct the problem prior to its causing a failure. For those cases where TV Electric identifies significanc degradation of carbon steel reactor coolant pressure boundary components as a result of boric acid corrosion. TU Electric will perform an engineering evaluation, including any appropriate root cause analysis, to identify both programmatic and hardware corrective actions.

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.CPSES'will enh:nce the current corrosion monit'oring program to minimize  !

degradation of the reactor coolant pressure boundary due to boric acid  !

corrosion. CPSES will develop and implement the program plan for Unit 1 by l June 1, 1989 and for Unit 2 prior to Unit 2 fuel load. Records of the program

! plan and results of the implementation of the program will be available for l your review at the CPSES site after the respective Units 1 and 2 fuel load.

Revised Concludina Paraaracht

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CPSES has implemented the procedural controls described above prior to the

' introduction of boric acid into the affected Unit 1 piping and compon'snts.

Unit 2 controls will be implemented similarly. Records associated with the implementation of these procedural controls are available for your review at the CPSES site for Unit I and will be available for Unit 2 after Unit 2 fuel load. .

Discussion:

Monitoring for boric acid corrosion has not been incorporated into the

" Corrosion Monitoring Program" because the Corrosion Monitoring Program addresses only the' internal corrosion of piping and vessels. Also, the practical' milestones for implementation are given, i.e., the implementing.

procedures for Unit I were put in place after June 1,1989, but prior to the introduction of boric acid into the components and piping identified to having the potential .for boric acid interaction with carbon steel reactor coolant

~ pressure boundary components. The initial response date of June 1, 1989, for developing and implementing the program plan for Unit 1, was based on the estimated fuel load date at the time of issuance of the letter.

Sincerely.

William J. Cahill, Jr.

s By: '

Jd(n W. Beck Vice President, Nuclear Engineering MCP/vid Attachment c - Mr. R. D. Martin, Region IV Resident Inspectors, CPSES (3)

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-UNITED STATES OF AMERICA-NUCLEAR REGULATORY COMMISSION

,. , s In the Matter of )

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L, Texas Utilities Electric Company ) Docket Nos. 50 445

) 50-446- *

(Comanche. Peak Steam Electric - ) _;

' Station,. Units 1 & 2) )

AFFIDAVII .j

.i l- John W. Beck being duly sworn, hereby deposes and'says that he is

! Vice President, Nuclear Engineering of TU Electric, the lead Applicant herein: '

that he -is duly authorized to sign and file with the Nuclear Regulatory- '

Commission this revised . response to NRC Generic Letter 88-05; that he is i l~ familiar _with the_ content thereof and that the matters set forth~therein are l- true and correct to the best of1 his knowledge, information and belief.

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Joff/ W. Beck W.k ~~

Vice President, Nuclear Engineerin6 1,

STATE OF TEXAS )

COUNTYSOF M )?

E Subscribed and sworn to befor me, a Notary Public, in and for M M , on L this ' o? 3 day of- 42P / , 1990. -

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L Notary Public (./ M My commission expires: .3 93 .

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