ML20206J597

Forwards Response to NRC Re Violations Noted in Insp Repts 50-327/86-62 & 50-328/86-62.Corrective Actions: Problem Identification Rept SQNEE86177 Issued on 861208 to Address Improper Sample Line Routing for Hydrogen Analyzer

ML20206J597
Person / Time
Site:	Sequoyah
Issue date:	04/08/1987
From:	Gridley R TENNESSEE VALLEY AUTHORITY
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 8704160130
Download: ML20206J597 (5)

Text

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TENNESSEE VALLEY AUTHORITY r CH ATTANOOGA, TENNESSEE 374o1 SN 157B Lookout Place APR 081987 i

U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555 Gentlemen:

In the Matter of ) Docket Nos. 50-327 Tennessee Valley Authority ) 50-328 SEQUOYAH NUCLEAR PLANT (SQN) UNITS 1 AND 2 - NRC-OIE REGION II INSPECTION REPORT NOS. 50-327/86-62 AND 50-328/86 RESPONSE TO VIOLATIONS Enclosed is our response to G. G. Zech's March 4,1987 letter to S. A. White which transmitted Notice of Violation Nos. 50-327/86-62-02 and 50-328/86-62-09 for SQN.

! Additionally, the fourth paragraph of G. G. Zech's letter to S. A. White referenced above identifies several items which Region II considers restart for SQN unit 2. Included in item 4 of that paragraph is "the Engineering Change Notice Closeout and FSAR update items addressed in the December 18, 1986 NRC letter." These items, tracked in the subject inspection report as Inspector Follow-up Items (IFIs) 50-328/86-62-02 and 50-328/86-62-13, were previously addressed in a letter from me to J. Nelson Grace dated February 3, 1987. As explained in our February 3, 1987 letter, resolution of ECN closeout and the FSAR update

( items is not associated with SQN restart.

If you have any questions, please get in touch with M. R. Harding at 615/870-6422.

To the best of my knowledge, I declare the statements contained herein are complete and true.

Very truly yours, TENNESSEE VALLEY AUTHORITY

- e R. Cridley, irector Nuclear Saf ty and Licensing Enclosure cc: See page 2 50 7 Ikho$k o

96, An Equal Opportunity Employer d I

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t U.S. Nuclear Regulatory Commission /\PR th81987 cc (Enclosure):

Mr. G. G. Zech, Assistant Director Regional Inspections Division of TVA Projects office of Special Projects U.S. Nuclear Regulatory Commission 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323 Sequoyah Resident Inspector Sequoyah Nuclear Plant 2600 Igou Ferry Road Soddy Daisy, Tennessee 37379 4-i 1

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i 1 ENCLOSURE RESPONSE - NRC-0IE INSPECTION REPORT NOS. 50-327/86-62 AND 50-328/86-62 GARY G. ZECH'S LETTER TO S. A. WHITE DATED MARCH 4, 1987 i

j Violation 50-327/86-62-02 and 50-328/86-62-09 i

10 CFR 50, Appendix B, Criterion III, as implemented by TVA's QA Topical Report TVA-TR-75-1 A, Rev. 8, paragraphs 17.1.3 and 17.2.3, requires that 1 measures be established and implemented to ensure that regulatory and design basis requirements are correctly translated into specifications, l

drawings, procedures and instructions.

Contrary to the above, critical installation requirements contained in the a

vendor's manual for the Consip Delphi, Inc. hydrogen monitors regarding sample line slope and insulation requirements were neither translated into the TVA installation nor appropriately dispositioned, i

This is a Severity Level IV Violation (Supplement I) and applies to

] Units 1 and 2.

I 1. Admission or Denial Of The Violation B

TVA admits the violation occurred as stated.

l 2. Reason For The Violation TVA received and approved the vendor instruction manual for the Consip Delphi, Inc., K-III hydrogen analyzer with installation instructions on December 19, 1978. The manual contained one page of

installation instructions which stated in part: " Connect the sample inlet and return lines to the analyzer cubicles. The large hole is provided to allow the insulation on the incoming line to extend all the way to the valve. The sample lines should be run in such a way that condensation will not be trapped and the return line should not

, be run vertieally a total of more than thirty feet." Also included in the instruction manual was Drawing No. 041020. " Piping and Instrumentation Diagram," showing incoming sample lines insulated.

Drawing No. 041020 was approved by TVA before placing it in the instruction manual.

The installation instructions in the vendor manuals were vague, were judged to be generic in nature, and were considered not applicable to SQN since SQN has an ice condenser containment. With an' ice condenser, the amount of steam present would be much less than '

non-ice-condenser containments when sampling begins 30 minutes after an accident. It was assumed that, since the lines would contain a flowing sample, the condensation would remain entrained in the sample gas. This conclusion proved to be incorrect. The sample line flow is not sufficient to entrain condensation in the sample, and pools of i

condensation'may be allowed to collect in the low points.

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In the case of the hydrogen analyzer, the lack'of clear installation instructions in the vendor manual and vendor-supplied drawings required the designer to make engineering evaluations of the sample line installation. Therefore, TVA admits that because of the ambiguous and brief' nature of the installation instructions, they were not properly dispositioned. However, as discussed in noction three of'this response, TVA is confident that the analyzers are fully operable. Furthermore, TVA is confident that this was an isolated incident and does not represent a programmatic deficiency.

3. Corrective Steps Taken and Results Achieved Problem Identification Report (PIR) SQNEEB86177 was-initiated December 8, 1986, to address the apparent improper sample line routing for the hydrogen analyzer. That PIR resulted in an analysis of the sample line routing and a subsequent calculation which evaluated the effect of condensation on the accuracy of the analyzer. This calculation shows that the effect of moisture condensation on the accuracy is a maximum of +0.5-percent hydrogen initially and within 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> drops to +0.2-percent hydrogen for the remainder of the accident period. This calculation-is conservative since it considers that all moisture in the sample condenses. In-actuality, the sample will cool only to saturation and the actual-error will be smaller. The vendor has recently verified that as much as six feet of moisture traps can be tolerated in the sample lines without affecting the analyzer accuracy. A.recent field inspection of the system shows the existence of one four-foot.and one six-inch condensation trap.

Additionally, this calculation has shown that the operability of the analyzers is not impaired since the amount of condensation is low and the effect of condensation on analyzer accuracy is small.

Furthermore, the sample pumps will pull 27 feet of water vacuum, and any condensation that does occur will be pulled through the sample lines to the moisture trap located upstream of the hydrogen analyzer detector. The collected condensate is returned to the' suction of the sample pump (located downstream of the analyzer detector). Since the gas sample is cooled (for pump seal protection) to a temperature .that will condense most of the sample moisture, the sample pump is designed to pump water continuously. Therefore, to pump this collected condensate back to containment along with the gas sample is within the design of the system. Based on the above evaluations,'TVA is confiden* that the analyzers are fully operable and no modificatico4 or further corrective actions are required. '

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4. Corrective Steps Which Will Be Taken To Avoid Further Violations TVA has procedures in place which require that all evaluations, judgments, and calculations be documented, reviewed and approved before being allowed into the design or the installation drawings.

TVA is confident that the procedures in place are adequate to prevent further violations of this type to occur.

5. Date When Full Compliance Will Be Achieved With the above procedures, SQN is in complete compliance.

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