ST-HL-AE-2843, First Interim Part 21 & Deficiency Rept Re Elastomer Diaphragms Contained in Comsip Delphi Containment Hydrogen Analyzers.Initially Reported on 881012.Unit 1 Regulator Replaced.Next Rept Will Be Submitted by 881216

First Interim Part 21 & Deficiency Rept Re Elastomer Diaphragms Contained in Comsip Delphi Containment Hydrogen Analyzers.Initially Reported on 881012.Unit 1 Regulator Replaced.Next Rept Will Be Submitted by 881216

ML20206E694
Person / Time
Site:	South Texas
Issue date:	11/14/1988
From:	Goldberg J HOUSTON LIGHTING & POWER CO.
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
REF-PT21-88, REF-PT21-88-150-000 PT21-88-150, PT21-88-150-000, ST-HL-AE-2843, NUDOCS 8811180163
Download: ML20206E694 (5)

Text

6 The Light company P.O. Box 1700 liouston. Texas 77001 (713) 228 9211 llouston Lighting 8e Power. _ - - - .- ..- - -. - - . . ~.. -----

November 14, 1988 ST-HL AE 2843 File No.: G12.443, G2.2 10CFR50.55(e)

U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 205

South Texas Proj ect Electric Generating Station Units 1 and 2 Docket Nos. STN 50 498, STN 50-499 First Interim Report Concerning Containment Hydrogen Analyzers On October 12, 1988 pursuant to 10CFR50.55(e) and 10CFR21, HL&P notified your office of an item concerning the Containment Hydrogen Analyzers.

Attached is the First Interim Report concerning this item. Our next report will be submitted by December 16, 1988.

If you should have any questions on this matter, please contact Mr.

M. F. Polishak at (512) 972 7071.

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J. H. Goldberg Group Vice President, Nuclear KM0/hg Attr,Sants: First Interim Report Concerning Containment Hydrogen Analyzers 9911180163 881114 POR S

ADOCK 05000490 I/./NRC/cy PDC f6[ I I

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A Sul,sidiary of Ilouston Industrin incorporatal l

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Ilouston Lighting & Power C<nupany L 2

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Regional Administrator, Region IV- Rufus S. Scott Nuclear Regulatory Commission Associate General Counsel 611 Ryan Plaza Drive, Suite 1000 Houston Lighting 6 Power Company Arlington, TX 76011 P. O. Box 1700 Houston, TX 77001 George Dick, Project Manager U.S. Nuclear Regulatory Co,nmission INPO Washington, DC 20555 Records Center 1100 Circle 75 Parkway Jack E. Boss Atlanta, CA 30339 3064 Senior Resident Inspector / Operations c/o U.S. Nuclear Regulatory Dr. Joseph M. Hendrie Commission 50 Bellport Lane P. O. Box 97.0 Bellport, NY 11713 Bay City, TX 77414 J. I. Tapia Senior Resident Inspector / Construction c/o U.S. Nuclear Regulatory Commission P. O. Box 910 Bay City, TX 77414 J. R. Newman, Esquire Newman & Holtzinger, P.C.

1615 L Street, N.W.

Warhington, DC 20036 R. L. Range /R. P. Verret Contral Power & Light Company P. O. Box 2121 Corpus Christi. TX '/8403 R. John Miner (2 copies)

Chief Oporating Officer City of Austin Electric Utility 721 Barton Springs Road Austin, TX 78704 R. J. Costello/M. T. Hardt City Public Service Board P. O. Box 1771 San Antonio, TX 76296 Revised 08/24/88 l

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. Attachment 1 ST-HL AE 2843 File No.: G12.443, G2.2 Page 1 of 3 First Interim Report Concerning Containment Hydrogen Analyzers I. Summary '

During startup testing on Unit 2, it was identified that the flow' regulators (6) furnished with the Comsip Delphi Containment Hydrogen Analyzers contained elastomer diaphragms. Also, one (1) of the flow regulators on Unit 1 contained an elastomer diaphragm. These flow regulators are located in a heated compartment of the Hydrogen Aaalyzer for sampling analysis. The flow regulators were qualified for 40 years with stainless steel diaphragms. The current equipment technical manual '

specifies diaphragus made of stainless steel; however, the flow regulators were not supplied with stainless steel diaphragms. The

• analyzers provide the Reactor Containment Building hydrogen concentration to the Control Room and provide continuous indication to tha operator for manually starting the Hydrogen Recombiners. Following a design basis accident, failure of the flow regulator because of unqualified diaphragms would prevent proper operation of the Hydrogen Analyzers. The inability to obtain an accurate hydrogen concentration could result in unsafe combustible levels of hydrogen inside containment and thus compromise containment integrity if the recombiners are not started when required.

Therefore, HL&P has determined that this deficiency if left uncorrected could have adversely affected the ability to mitigate an accident. This item is reportable pursuant to 10CFR50.55(e) and 10CFR21.

II. Description of the Deficiency The Comsip Delphi Hydrogen Analyzers were shipped with elastomer flow regulator diaphragms in 1979. The original equipment qualification plan indicated that the elastomer diaphragms were to have a 5 year design life. Subsequent to the developmant of the equipment qualification plan, Comsip submitted documentation in Harch, 1983 identifying to HL&P that the flow regulators located in a staled heated compartment were provided with stainless steel diaphragas. In this submittal, Comsip did not identify that the diaphragms currently installed in STP equipment were elastomer in conflict with their previously submitted design documentation. This later documentation was subsequently used by Wyle Laboratories as a basis for their qualification analysis which states a 40 year qualified life for the flow regulator with a stainless steel diaphragm.

The hydrogen analyzers were insta11eo with the elastomer diaphragms as

! originally shipped. Review of the equipment history revealed that five of the six flow regulators (3 per Hydrogen Analyzer) in Unit I had been i replaced in 1937 due to excessive leakage. The replacement regulators purchased from Comsip were properly specified with stainless steel diaphragms.

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Attachment 1 ST-HL-AE-2843 File No.: G12.443, C2.2 Page 2 of 3 F

General Design Criterion 41 of 10CFR50, Appendix A requires that systems to control the concentrations of hydrogen and other substances which may be released into containment be provided te casure containment integrity is maintained following an accident. The Class 1E hydrogen analyzers are designed to provide continuous indication of the Reactor Containment Building hydrogen concentration levels to the Control Room and form the basis for manually starting the hydrogen recombiners. The recombiners are started when the hydrogen levels approach 3.5% by volume.

Following a design basis accident, it was conservatively assumed that failure of these flow regulators due to the use of the unqualified diaphragms could cause the regulators to fail fully open. In this position, the monitors would indicate a lower hydrogen concentration than actually exists inside containment. Unsafe levels of hydrogen (4 percent by volume is specified as the lower combustible limit of hydrogen in air) may be reached following a LOCA because proper operator action would not be taken to start the hydrogen recombiners due to inaccurate indication i of hydrogen concentration levels. Also, sheuld the recombiners be started with a concentration above the 4 percent by volume limit due to inaccurate indication, containment integ.ity may be compromised.

Although sampling capability exists to determine hydrogen concentration levels following an accident, there is no procedural guidance to ensure sampilng of the cont tinment atmosphere at specified intervals.

Therefore, th' potential existed to exceed the 4 percent by volume limit.

III. Corrective Action The remaining Unit 1 ilow regulator has been replaced with a regulator containing a stainless steel diaphragm. Unit 2 regulators with stainless steel diaphragms will be installed prior to fuel load.

IV. Recurrence Control The Comstp Delphi hydrogen analyzer operation / maintenance manual reflects stainles s steel diaphragms for these regulators. Any future replacement regulator purchases will be stainless steel, i This deficiency has been evaluated and it has been determined that this event is solely attributable to Comsip Delphi documentation. No HL&P recurrence control neasures are required. A review of Comsip Delphi equipment supplied for use at STP will be performed to determined if similar deficiencies exist. The result of this evaluation and further recurrence control measures will be addressed in the Final Report.

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I Attachment 1 ST-HL-AE-2843 File No.: G12.443, G2.2 Page 3 of 3 V. Safaty Analysis Following a design basis accident, the hydrogen concentration inside containment may exceed the 4 percent by volume limit as a result of inaccurate indication by the hydrogen analyzers. Prol.or operator action may not be taken to start the Hydrogen Recombiners. Ui. safe combustible levels of hydrogen may compromise the integrity of the F.eactor Containment Building. Therefore, HL&P has concluded that this deficiency could result in a substantial safety hazard if icft uncorrected, ana is reportable pursuant to 10CFR50.5S(e) and 10CFR21.

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