ML19318D227

Forwards Rept on Insp Program Re Sys Performance Which Was Initiated in Response to IE Insp Rept 50-327/80-15.Insp Program Should Ensure Sys Performance Will Not Be Degraded

ML19318D227
Person / Time
Site:	Sequoyah
Issue date:	06/27/1980
From:	Mills L TENNESSEE VALLEY AUTHORITY
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
NUDOCS 8007080220
Download: ML19318D227 (12)

Text

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~_4 TENNESSEE VALLEY AUTHORITY CH ATTANOOGA. TENNESSEE 374ot 400 Chestnut Street Tower II

• June 27, 1980 Mr. James F O'Reilly, Director Office of Ins ction and Enforcement U.S. Luclear ' ulatory Commission aegion II - Suit 3100 101 Marietta Stree Atlanta, Georgia 3 03

Dear Mr. O'Reilly:

SUqUOYAli hbCLEAR PLANT UNIT 1 - NRC-01E REGION II LETTER RII:LH 50-327/80 INSPECTION REPORT - ADDITIONAL INFORMATION ON INFRACTION The subject letter dated March 21, 1980, cited TVA with one infraction 1 in accordance with 10 CFR 2.201. A response to that infraction was submitted on June 12, lWO. Enclosed is a report on the inspection program initiated as a result of that infraction.

TVA is confident that the inspection program specified in the enclosure

. is adequate to ensure systeu performance will not be degraded. The con-servatism used in design, conbined with the formal controls used in construction and operation, are sufficient to prevent even random failures of individual components from degradin overall system per-formance under worst case conditions.  !

l TVA believes the inspection and analyses performed so far are sufficient to demonstrate that the piping and piping support systems on Sequoyah unit 1 are fundamentally sound and that low-power operation of the unit would be unaffected by even the most severe discrepancies that could be found.

If you have any questions concerning this matter, please get in touca with D. L. Lambert at FTS 857-2581.

Very truly yours, TENUESSEE VALLEY AUTHORITY L. M. Mills, Manager Nuclear Regulation and Safety Enclosure fsol 3 1

cc: Mr. Victor Stallo, Jr., Director (Enclosure) l Office of Inspection and Enforcement l U.S. Nuclear Regulatory Commission /[

Washington, DC 20555 An cual Opportunity E. m er 8007080 2k

ENCLOSURE 3

SEQUOYAH NUCLEAR PLANT UNIT 1 INFRACTION 327/80-15 INSPECTION FINDINGS I. Introduction An inspection was conducted by the Nuclear Regulatory Commission on April 23-25, 1980, to determine Sequoyah Nuclear Plant unit 1 compliance with IE Bulletin 79-14, " Seismic Analyses for As-Built Safety-Related Piping Systems." The results of this inspection indicated to the in'spector that TVA's program of verifying the proper installation of piping supports ,

had not been properly implemented in the systems inspected.

• A Confirmation of Action letter was issued to TVA on April 29 by James P. O'Reilly, Director of Office of Inspection and Enforcement fo~r Region II. The letter listed the following specific requirements.

1. Determine the cause of the problem in implementing your piping

• and support program, including the reasons for the failure of your quality assurance program to identify the problem.

2. Inspect a representative sample of pipe supports on each safety-related system inside containment to verify proper installation.

The percentage to be inspected will be based on the findings from.the determinations in paragraph 1 above and following

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• discussions with this office.

3. Select at least one isometric drawing from each of eight safety-related systems inside containment and verify that all requirements of IE Bulletin 79-14 are met. -

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4. Upon completion of the above, provide us with your inspection findings, schedule for completion of the inspection of the remainder of the safety-related supports outside containment, and proposed corrective actions.

A followup letter to Mr. O'Reilly from L. M. Mills on May 6,1980, requested that item 3 be revised as follows.

Select at least one isometric drawing from each of eight safety-related systems inside containment and verify proper installation of pipe supports. Select at least one isometric drawing fror. each of eight safety-related systems outside containment and verify that all the requirements of IE Bulletin 79-14 are met. These eight systems shall include the residual heat removal (RHR), auxiliary feedwater (AFW), safety injection (SI), and upper-head injection (UHI) systems.

The following reports the results of the inspection program established by TVA to comply with the requirements of the Confirmation of Action letter, ,

and is l'ntended as the final response to that letter. -TVA proposes further 1 inspections to be performed, and a final response to IE Bulletin 79-14 will be issued upon completion o'f the subject inspections.

II. Inspection Findings l

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- i A. Description of Inspection Program <#

l An inspection program was established which exceeded the requirements I specified in the Confirmation of Action letter. The program was

. intended to ensure that any significant problems on safety systems i

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. S inside containment were found and corrected.- All significant physical discrepancies identified by the program will be corrected before initial criticality.

Maintenance Instruction 6.17, " Instructions for the Implementation of NRC OIE Bulletin 79-14," provided the original program for inspection

,and review of supports and configuration. In addition, a walkthrough i

inspection of the safety-related supports inside containment was 1

performed. Division of Nuclear Power (NUC PR) certified inspectors ' '

I performed the inspections required by MI-6.17. Division of Construction i

(CCNST) certified inspectors and Division of Engineering Design (EN DES) engineers assisted in performing verifications on items -

where questions arose.

, The inspection program consisted of the following.

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1. Inspection of Supports on Safety-Related Systems Inside Containment A detailed inspection was performed on approximately 22 percent of engineered supports installed inside containment, as shown on the major isometrics for the 12 systems specified. This inspection included:

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a. All supports on one isometric analysis drawing for the j following systems:

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. l (1) Reactor coolant ..

(2) Residual heat removal , 1 (3) Safety injection l

(4) Chemica,1 and volume control (5) Auxiliary feedwater (6) Main steam (7) Component cooling <

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(8) Main feedwater j Also included-in this portion of the inspection were checks to l I

see that supports that had been voided had in fact been removed.

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b. On 4 additional systems, at least 20 hangers for each . 1 system were randomly selected from the appropriate isometric for inspection. Those systems were:

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l (1) Upper-head injection l

(2) Containment spray (3) Steam generator blowdown l

(4) Emergency raw cooling water  !

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c. In cases where piping from one of'the systems being inspected  ;

passed through a support that also included piping other than those included in the identified isometrics, the l

entire " gang hanger" was inspected for all systems affected.

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2. Isometric Walkdown Inspection Inside Containment In order to ensure that potential problem supports inside 1

containment were. discovered and corrected, walkdown inspections of major isometrics on the 12 safety-related systems inside containment were performed. These inspections consisted of inspecting the piping configuration and approximate support location against the latest revision of the analysis isometric.

Specific checks were made to ensure'that (1). piping and valve ,

configuration was as shown, (2) supports were installed in the proper location and were functional, and (3) to identify missing or additional supports. In general, dimensional checks were not made unless a discrepancy was suspected; and then a more det' ailed inspection was performed.

9 Walkdown dnspections were made_ by teams of NUC PR and CONST certified inspectors, supported by EN DES analysis engineers; and results were reviewed by CONST engineers and EN DES analysis engineers.

3. Detailed Hanger Inspection Outside Containment

.o Outside containment, the same 12 systems plus the fuel pool

. cooling system were inspected to the same level of detail as those inside centainment. .Again, at least one isometric was selected for each system; and all supports shown were subjected to a detailed configuration inspection.

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4. Piping Configuration Inspections on Eight Isometrics Outside ..

Containment The same portions of piping systems outside containment that received detailed hanger inspection were inspected to the full extent of IE Bulletin 79-14, including pipe run geometry; support and restraint design, locations, function, and clearance; embedments; pipe attachments; and valve and valve operator locations and weights. ,

B. Description of Review of Data Obtained Each individual data package, including marked up copies of drawings showing the condition as found by inspectors, was reviewed in detail by a series of engineers. An initial screening was done by a site engineer to ensure that appropriate data was prop'erly recorded and any obvious discrepancies were flagged. All data packages were then given to a team of design engineers, onsite specifically for this review. The design engineers analyzed as necessary to determine whether the support was acceptable. Problems that could not be handled onsite were sent to EN DES in Knoxville for further evaluation.

Problem hangers were evaluated in light o' Technical Specifications and appropriate action statements were invoked where applicable.

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s An additional review was performed on all data packages for the detail hanger inspection inside containment. A team of engineers, one each from EN .T.S, CONST, and NUC PR, reviewed in careful detail all discrepancies to determine the specific type of problem and the cause for that problem. The information obtained from this review was used to determine what further checks, if any, were required to ensure all potential problems'could,be identified and corrected.

This provided the basis for performing the additional walkdowns inside containment using isometric analys'is drawings and is also the .

basis for determining further inspection requirements.

Criteria used for determining the acceptability of a deficiency were extremely conservative. In general, discrepancies were analyzed on an individual basis within the bounds of existing analysis. A total reanalysis of the entire isometric problem was not done to determine acceptability. Therefore, as-found conditions that might be slightly i

out of tolerance were frequently determined to be unacceptable, even though a more detailed analysis of the apparent discrepancies may show many discrepancies to be inconsequential.

C. Discussion of Findings The results of the inspection program described revealed that the Quality Assurance Program is essentially sound. Discrepancies found were randomly distributed through several phases of the design, construction, and operation process, and did not fall into any one

category to a degree necessary to be identified as a trer.d er to -'

indicate a breakdown in the program. The program as it presently exists has evolved over the past six years, and controls were not always as formal as they are now. The inspection program being performed was designed to uncover the types of problems expected to result from the evolutionary process, and examination of inspection findings has verified that those types of problems are being found.

Areas where problems were identified on.Sequoyah unit 1 can be summarized as a need for:

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1. Improvement of communications between the design engineer and

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constructor with regard to acceptance criteria, especially as related to clearances.

2. Increased formalization of lesign interface controls, especially with regard to the link between field modifications and subsequent reanalysis.

3. Expanding the inspection program to cover overall system configuration, as w'll as the full details of discrete pieces, l l

as is presently done.

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- , l TVA is confident that the inspection progr'am specified herein is 1

fully adequate to ensure overall system performance will not be  !

degraded. The conservatism used in design, combined with the formal I

controls used in construction and operation, are sufficient to prevent i

even random failures of individual components from degrading overall l l

system performance under worse case conditions.

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'III. Schedule for Completion of Inspection and Corrective Action TVA believes the inspectioc rad salyses performed so far are sufficient to demonstrate that the piping and piping support systems on Sequoyah unit 1 are lundamentally soind, and that low-power operation of the unit -

would be unaffected by even the most severa discrepancies that could be found.

TVA believes that additic:.ai inspections are necessary to provide further ,

assurance that the plant can be operated safely at full power. The inspection program will consist of the following.

n. Perform isometric walkdown inspections associated with the remain'ing safety-related systems inside containment.

B. Perform isometric walkdown inspections associated with the safety systems outside containment.

C. Inspect three supports on each side of rotating equipment for proper clearance.

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D. Perform a walkdown inspection of supports on piping 2-1/2 inches or larger that were analyzed with the alternate criteria method on the ERCW, component cooling, waste disposal, CVCS, fuel pool cooling, and fire protection systems in class I structures. Systems not )

included are ice condenser glycol, auxiliary boiler, primary water, and roof drain systems, since they perform no safety function.

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E. Perform valve and material verifications on the eight isometrics inspected outside containment.

F. Perform valve and material input information verifications on

. rigorously analyzed systems on a sample basis to consist of three valves for each isometric and material verification at three welds for each isometric.

G. Formal procedures will be written to ensure that discrepancies found -

are appropriately reviewed at.d technical specification action statements invoked, if appropriate, within 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> from the time the design

- engineer performing the review is notified of the discrepancy. This is in accordance with IE Bulletin 79-14.

Of the inspections specified, all but item D will be completed before 30 offective full-power days fuel burnup on unit 1. Item D will he coupleted before restart from the first refueling outage. This is ,

justified based on the inherent conservatisu of the alternat'e' criteria method. Thirty effective full-power days is a power history at which a very low fission product inventory is accumulated, and decay heat levels present in the core will be low. *

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All discrepancies that have a definite potential for causing a loss of pressureboundaryduringaseismicevektandthoseinaccessiblesupports classified as having a minimum potential for causing a loss of pressure boundary will be repaired before initial criticality.

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TVA believes that the program described above is fully adequate to ensure safe operation of Sequoyah unit 1.

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