ML20043G569

LER 90-007-00:on 900515,determined That Concentration of Old Bottle of Ammonia Span Gas Not within Spec Causing Ammonia Trip Setting to Be Nonconservative.Caused by Incorrect Certification by Vendor.Bottle replaced.W/900615 Ltr

ML20043G569
Person / Time
Site:	Vermont Yankee File:NorthStar Vermont Yankee icon.png
Issue date:	06/15/1990
From:	Pelletier J, Reid D VERMONT YANKEE NUCLEAR POWER CORP.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-90-007, LER-90-7, VYV-90-208, NUDOCS 9006200442
Download: ML20043G569 (5)

Text

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VERMONT YANKIcic NUCLEAR POWER CORPORATION P. O. BOX 157 GOVEltNOR !!UNT ROAD VERNON, VERMONT 05354 June 15, 1990 VYV# 90-208 U.S. Nuclear Regulatory Commission Document Control Desk Washington, D.C. 20555

REFERENCE:

Operating License DPR-28 Docket No. 50-271 Reportable Occurrence No. LER 90 07

Dear Sirs:

9 As defined by 10CFR50.73, we are reporting the attached Reportable Occurrence as LER 90-07.

Very truly yours, VERMONT YANKEE NUCLEAR POWER CORPORATION Donald A. Reid Plant Manager cc: Regional Administrator USNRC Region I 475 Allendale Road King of Prussia, PA 19406 9006200442 900615 PDR S

ADOCK 05000271 PDC

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NRC F rm* 366 U.S. NUCLEAR REGULATORY COMMISSION APkROVED OMS NO.3150-0104 (6-89)

• EXPIRES 4/30/92 ESTIMATED BURDEN PER RESPONSE TO COMPLY WITH THIS INFORMATION COLLECTION REQUEST:

50.0 HRS. FORWARD COMMENTU REGARDING t LICENSEE EVENT REPORT (LER) BURDEN ESTIMATE TO THE RECORDS AND REPORTS MANAGEMENT BRANCH (P-530), U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555, AND TO THE PAPERWORK REDUCTION PROJECT (3160-0104), OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON. DC 20603.

FACILITY NAME (5) DOCKET NO. (8) PAGE (*)

VERMONT YANKEE NUCLEAR POWER STATION Ol5l0l010l2l7l1 0 l 110F l 0 l 4 TITLE (*) Toxic Gas Monitor Ammonia Gas Trip Point Error Due to Wrong Concentration in Span Gas Bottle EVENT DATE (5) LER NUMBER (*) REPORT DATE (') OTHER FACILITIES INVOLVED (*)_

MONTH DAY YEAR YEAR SEQ. # REV# MONTH DAY YEAR FACILITY NAMES DOCKET NO.(S) 0 5 0 0 0 0l5 1l5 9l0 9l0 -

010l7 -

0l0 0l6 1l5 9l0 0 5 0 0 0 OPERATING THIS REPORT IS SUBMITTED PURGUANT TO REQ'MTS OF 10CFR 4: / ONL OR MORE ()

MODE (*) N 20.402(b) __ 20.405(c) __ 50.73(a)(2)(iv) __ 73.71(b)

POWER __ 20.405(a)(1)(I) __ 50.36(c)(1) __ 50.73(a)(2)(v) __ 73.71(c) >

LEVEL ($*) Il d 0 20.405(a)(1)(II) __ 50.36(c)(2) __ 50.73(a)(2)(vii) __

OTHER:

............... _ 20.405(a)(1)(III) _x 50.73(a)(2)(I) __ 50.73(a)(2)(viii)(A)

............... ._ 20.405(a)(1)(iv) __ 50.73(a)(2)(II) __ 50.73(a)(2)(viii)(B)

,.,............ 20.405(a)(1)(v) 50.73(a)(2)(III) 50.73(a)(2)(x)

LICENSEE CONTACT FOR THIS LER (se)

NAME TELEPHONE NO.

AREA CODE JAMES P. PELLETIER, PLANT MANAGER dd2 2ld7l-l7l7l1l1 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT ('*)

CAUSE SYST COMPNT MFR REPORTABLE ..... CAUSE SYGT COMPNT MFR REPORTABLE ......

TO NPRDS ..... TO NPRDS ......

N/A l lll lll l N/A l lll lll ll N/A l lll lll l . N/A l lll lll . l SUPPLEMENTAL REPORT EXPECTED ($*) EXPECTED M0 DA YR SUBMISSION

~~l YES (If ves, complete EXPECTED SUDMISSION DATE) x l NO DATE ($5) l l l ABSTRACT (Limit to 1400 spaces, i.e., approx. fifteen single-space typewritten lines) ($*)

On 4/19/90, with the plant at 100% steady state power, Instrument and Control spe-cialists were performing an ammonia span gas bottle changeout for the toxic gas monitor (EIIS=45) (TGM). Once the new bottle was in place, the concentration of the gas was me: Cured. The measured concentration of the new span gas bottle was less than its certified c ncentration and outside of the allowable tolerance. The old bottle was placed back in c rvice and the new bottle sent out for analysis.

The results of the analysis on the new bottle confirmed that the concentration was within the tolerance allowed and was subsequently returned for use. Based upon this, on 5/15/90, it was determined that the concentration of the old bottle was not within speci-fication which caused the ammonia trip setting to be non-conservative from the period 1-29-90 to 5-14-90.

The new span gas bottle was immediately installed and the instruments recalibrated.

The root cause of the event is the incorrect certification by the vendor of the con-centration of ammonia in the span aas previous 1v supplied.

NRC Form 366 (6-09)

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. t NRC F;rm,366A U.S. NUCLEAR REGULATORY COMMISSION APPROVED OMS NO.3150-0104 l (6-89) EXPIRES 4/30/92 ESTIMATED BURDEN PER RESPONSE TO COMPLY i

WITH THIS INFORMATION COLLECTION REQUEST:

50.0 HRS. FORWARD COMMENTS REGARDING LICENSEE EVENT REPORT (LER) BURDEN ESTIMATE TO THE RECORDS AND REPORTS TEXT CONTINUATION MANAGEMENT BRANCH (P-530), U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555, AND TO THE PAPERWORK REDUCTION PROJECT (3160-0104), OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, DC 20603.

UTILITY NAME (') DOCKET NO. (8) LER NUMBER (*) PAGE (*)

YEAR SEO. # REV#

t VERMONT YANKEE _ NUCLEAR POWER STATION d d d d d 2l 7l 1 9l0 -

0l0l7 -

0l0 d2 0F d4 TEXT (If more space is required, use additional NRC Form 366A) (5')

DESCRIPTION OF EVENT On 4/19/90, Instrument and Control specialists were performing a changeout of the ammonia span gas bottle for the toxic gas monitor system. Prior to the changeout, the ana-lyzer was calibrated to the standard that was currently in use, which was certified to 266 ppm ammonia.

A new spar gas bottle was installed which was certified to contain 277 ppm ammonia.

Per procedure, the new span gas is compared to the old standard before the analyzers are r calibrated. From that comparison, it was determined that the new span gas concentration was reading 211 ppm 24% lower than it was certified for.

The new ammonia span gas bottle was returned to the vendor for retesting. On 5/14/90, the. retested bottle was released f rom Quality Control with a re-certification of 281 ppm ammonia. This bottle was again installed in the toxic gas monitor and when compared to the old span gas bottle it indicated 213 ppm which is also 24% lower than it was cer-tified for.

Based on this, on 5/15/90 it was determined that the old span gas bottle was incorrectly certified. This resulted in a non-conservative indication and trip setting, of the toxic gas monitor.

A similar problem with span gas concentration had previously been identified during bottle changeout in 1989. At that time one of the corrective actions was to revise the pro-

-c: dure to require a calibration to the old standard before the change and a comparison of th) analyzer indication af ter change of the span gas. This revision was in review at the time the span gas was changed in January but had not yet been approved and no comparison was performed at that time.

CAUSE OF EVENT The root cause of the event is the incorrect certification by the vendor of the con-c;ntration of ammonia in the span gas previously supplied.

A major contributing f actor in the event is the reactivity of the ammonia gas which C;kes analysis of the gas at the low concentrations required extremely difficult.

Another contributor was that the procedure revision initiated due to prior concerns with the concentration of new span gas bottles was not in place at the time of the span gas rcplacement in January. At that time there were no procedural requirements to compare span NRC Form 366A (6-89) -

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NRC FCr3 366A U.S. NUCLEAR REGULATORY COMMISSION APPROVED OMS NO.3150-0104 (6-89) ' EXPIRES 4/30/92 ESTIMATED BURDEN PER RESPONSE TO COMPLY  !

f WITH THIS INFORMATION COLLECTION REQUEST:

50.0 HRS. FORWARD COMMENTS REGARDING LICENSEE EVENT REPORT (LER) BURDEN ESTIMATE TO THE RECORDS AND REPORTS TEXT CONTINUATION MANAGEMENT BRANCH (P-530), U.S. NUCLEAR l REGULATORY COMMISSION, WASHINGTON, DC 20555, AND TO THE PAPERWORK REDUCTION PROJECT (3160-0104), OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, DC 20603.

UTILITY NAME (') DOCKET NO. (*) LER_ NUMBER (*) PAGE (a)

YEAR SEO. # REV#

VERMONT YANKEE NUCLEAR POWER STATION d d d d d 2l 7l 1 910 -

0l0l7 -

0l0 d3 0F d4 TEXT (If more space is required, use additional NRC Form 366A) ()

gases during bottle replacement and subsequently the difference in concentration was not identified when the span gas was replaced. This revision since has been approved and was re:ponsible for the identification of this event.

ANALYSIS OF EVENT The discrepancy in the gas concentration of the original bottle caused the alarm set-p int to be greater than that allowed by tech specs. The tech spec. requirement is for the toxic gas monitor to alarm at a concentration of 75 ppm of ammonia gas. With the lower thin certified gas concentration, the actual trip point was 80.87 ppm, While the setpoint was above the tech, spec, requirement, the toxicity level as rcferenced by Reg. Guide 1.78 is 100 ppm for ammonia. Therefore, the toxic gas monitor system would have tripped and performed its function well before any toxic ammonia gas levels were reached.

Based on the above, there were no potential health or safety implications to plant-personnel or the public.

CORRECTIVE ACTIONS The immediate corrective actions were:

1. The span gas bottle was changed with the new one that had been tested, and verified by a second test to be correct.

2. The instruments were recalibrated to agree with the concentration in the new span gas.

Long term corrective actions:

1. Return the bottle that was removed to the vendor for further testing to determine the actual concentration.

2. Complete a vendor evaluation, by our Quality Assurance Department, to determine the continuing acceptability of their product.

3. Pursue an evaluation to justify the elimination of the toxic gas monitor system.

This subject has already been discussed with NRR. -

NRC Form 366A (6-89)

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. , *o NRC Form 366A U.S. NUCLEAR REGULATORY COMMISSION APPROVED OMS NO.3150-0104 (6-89)' EXPIRES 4/30/92

• ESTIMATED BURDEN PER RESPONSE TO COMPLY WITH THIS INFORMATION COLLECTION REQUEST:

50.0 HRS. FORWARD COMMENTS REGARDING LICENSEE EVENT REPORT (LER) BURDEN ESTIMATE TO THE RECORDS AND REPORTS TEXT CONTINUATION MANAGEMENT BRANCH (P-530), U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555, AND TO THE PAPERWORK REDUCTION P90 JECT (3160-0104), OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, DC 20603.

UTILITY NAME (') DOCKET NO. g*) LER NUMBER (*) PAGE (*)

YEAR SEQ. # REV#

VERMONT YANKEE NUCLEAR POWLR STATION d d d d d 2l 7] I 9l0 -

0l0l7 -

0l0 d4 0F d4 TEXT (If more space is required, use additional NRC Form 366A)-(i')

Since the corrective actions implemented due to previously identified discrepancies in gas concentration were inst!wmental in identifying this event, they are felt to be suf-ficient to prevent recurrence and no additional corrective actions besides those above are necessary.

ADDITIONAL INFORMATION A similar incident was reported in 1987 as LER BT-03.

i NRC Form 366A (6-89)

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