ML20028H843

LER 90-024-00:on 901228,pretreatment Monitoring Station Offgas Samples Not Collected & Analyzed within 4 H of Increased Fission Gas Release.Caused by Misinterpretation of Tech Specs.Personnel instructed.W/910125 Ltr

ML20028H843
Person / Time
Site:	Hatch
Issue date:	01/27/1991
From:	Hairston W, Tipps S GEORGIA POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
HL-1447, LER-90-024, LER-90-24, NUDOCS 9101300283
Download: ML20028H843 (8)

Text

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'Geoga Power Company

. ,, . 333 P;edmont Avera;e ,

- Atlanta Georgia 30308-Telephors' 404 526 3195 -

, Mahrq Addrets

~ 40 hverness Center Parkwtw Post 0+fce Box 1295

.- D rtrWegham. Alabama 35201 Wephone 205 868 Sa81 tw sounern etexinc svsMn

' W. G. Hairston, lH -

Senior Vice hesident

_ Hucier Opera!.ons l

HL-1447 0000216 January 25, 1991 U.S. Nuclear l Regulatory Commission ATIN:. Document Control Desk Washington, D.C.- 20555-PLANT =E. I. HATCH - UNITS 1, 2

.NRC DOCKETS-50-321, 50-366 OPERATING LICENSES OPR-57, NPF-5

' LICENSEE EVENT REPORT' 0FFGAS SAMPLES NOT COLLECTED AND ANALYZED AS' REQUIRED BY-TECHNICAL SPECIFICATIONS ,

Gentlemeni In' 'accordance with the -requirements 'of 10 -CFR 50.73(a)(2)(i),

Georgia Power Company (GPC) is' submitting 'the enclosed Licensee Event

. Report-(LER) concerning Offgas Samples that were not collected 'and analyzed as crequired by the Technica1' Specifications, This event occurred at LPlant Hatch'- Units 1 and 2. -

If you have any questions in -this regard,-please call this office.

Sincerely, tJ, h. /(wb$J.h--

W. G. Hairston, III WGH/rw.-

Enclosure:

LER 50-321/1990-24

=c:- (See next page.)

91o1300283 91o127 I

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, Georgia Power A U.S. Nuclear Regulatory Commission January 25, 1991 Page Two c: .G_qoraia Power Company Mr. H. L. Sumner, General Manager - Nuclear Plant Mr. J. D. Heidt, Manager Engineering and Licensing - Hatch NORMS V.S. Nuclear Reaulatory Commission. Washinoton. D.C.

Mr. K. Jabbour, Licensing Project Manager - Hatch U.S. Nuclear Reaulatory Commission. Reaion 11 Mr. S. D. Ebneter, Regional Administrator Mr. L. D. Wert, Senior Resident Inspector - Hatch

U.S. WCLEAk LECAAIJ1 CONS 513 AMMD C4 C. 3NM

%(DP)U orm L% EXP12ES: 4/30/92 LICENSEE EVENT REPORT (LER) fACILIII hake (1) 00CAEI hvM6ER (2) F Af F rTi PIM E ilATQl, UNIT 1 05000321 L lg, l 6 IITLE (<.)

0FFCAS SAMPLES NC7r COLIELTED AND ANALYZED AS Rf1711 RED BY TECINICAL SPECIFICATIONS EVEh! DATE (5) LER huMBER (6) REPORI DATE (7) OlhER FACILti!ES lhv0LVED (8)

Mozih DAV YEAk YLAR SEQ HUT i REV MONIH DAY VEAR FACILl!Y NAMES DOCAEI hum 8ER(S)

PIR C llATQi, UNIT 2 05000366 12 28 90 90 024 00 01 27 91 05000 IHis kEPoki is $4Ml 'IED PURSUAhi 10 H:E REQUIREMEhls of 10 CfR (11)

OPERAT!hc ~

MODE (9) 1 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 i 00 20.405(a)(1)(II) 50.36(c)(2) 50.73(a)(2)(vil) OTHER (Specify in

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20.405(a)(1)(lit) T 50.73(a)(2)(1) 50.73(a)(2)(vill)(A) Abstract betow)

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20.405(a)(1)(iv) ~~

50.73(a)(2)(lf) -

50.73(a)(2)(viii)(B) 20.40$(a)(1)(v) 50.73(a)(2)(til) 50.73(a)(2)(x)

LICENSEE CONIACf FOR THis LER (li) 4AME TELEPMohE huMBER NREA CODE STEEN B. TIPPS. MANAGER NUCLEAR SAFF!rY AND COMPLIANCE. IIATOI 912 367-7851 COMPLETE ONE LihE FOR EACH FAILURE DESCRIBED IN THis REPORT (13)

COMPONENT MAkUFAC. R P RT CAUSE SYSTEM COMPONENT AC* I CAUSE BYSTEM yUR ppDS M9gA NU[g R Efp SUFFLEMENIAL REPORT EXPECIED (14) MohiH DAV VEAR EXPECTED SUBMISSION

] YES(if yes, complete EXPECTED SUBMISSION DATE) DATE (15)

% NO AF.STRACI (16)

On 12/28/90 at approximately 0800 CST, Unit 1 and Unit 2 were in the Run mode at an approximate p0wer level of 2436 C&'T (approximately 100% rated thermal power). At that time, it was determined the requirements of Unit 1 Technical Specifications Section 4.15.2.7.2.b and Unit 2 Technical Specifications Section 4.11.2.7.2.b had not been met. Specifically, representative samples of gases at the pretreatment monitoring station were not always collected and analyzed within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> of an increase of greater than 50% in a nominal steady-state fission gas release value as required by the aforementioned Technical Specifications. It is highly unlikely any Technical Specifications offgas pretreatment activity limits were exceeded. The fission gas release values were a small fraction of the limit, and samples were routinely collected and analyzed to confirm the calibration of the pretreatment monitors.

The cause of this event was a misinterpretation of the Technical Specifications requirements. Contributing to the event were ambiguous Technical Specifications.

Corrective actions include providing the correct interpretation of the requirements to Chemistry personnel, issuing a Technical Specifications Clarification, and reviewing Chemistry procedures.

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TEXT CONTINUATION r,ACILITY NAME (1) DOCKET NUMBER (2) LER NUMBER (5) PAGE (3)

YEAR SEQ hum REV PLN G HATCH,' UNIT 1 05000321 90 024 00 2 0F 6 ILu PLANT AND SYSTEM IDENTIFICATION-General Electric Boiling Water Reactor Energy Industry Identification System codes are identified in the text as -(EIIS-

-Code XX).

SUKMARY OF EVENT On 12/28/90 at approximately 0800 CST, Unit 1 and Unit 2 were in the Run mode at an approximate power '1evel of 2436 CMVT (approximately 100% rated thermal-

~

power). At that time, it was determined the requirements of Unit- 1 Technical Specifications Section 4.15 2.7.2.b and Unit 2 Technical Specifications Section 4.11.2.7.2.b had not been met. Specifically, representative samples of gases at the pretreatment monitoring station were not always collected and analyzed within-4 hours of an increase of greater than 50% in a nominal steady state fission gas release _value as required by the aforementioned Technical <

Specifications. It_is highly unlikely any Technical Specifications offgas

_pretreatment activity 1imits were exceeded. The fission gas release values were-

~

a cmall-fraction of the limit, and samples were. routinely collected and analyzed '

to confirm the calibration of_the pretreatment monitors. .

The cause of_this event was a misinterpretation of the Technical Specifications requirements. Contributing to the event were ambiguous Technical Specifications.

Corrective' actions: include providing the correct. interpretation of'the requirements to Chemistry' personnel,-issuing a Technical Specifications Clarification, and reviewing Chemistry procedures.

DESCRIPTION '0F THE EVENT During a routine audit, plant Safety Audit and Engineering Review personnel reviewedf a sample of Unit 1 and Unit 2 offgas ^protreatment activity data sheets -

for 1990. Plant Chemistry personnel complete these_ data-sheets once per day, recording the pretreatment monitor (EIIS, Code IL) reading,' calculating the current activity release rate, and comparing the current: release rate with a nominal steady-state release rate. This is done in order to determine whether the release rate has increased by more -than -50% over the nominal steady-state release ~ rate and whether a sample of gases at the_ pretreatment monitoring ,

station must be _ collected and analyzed. These_ actions are performed to meet the requirements of Unit 1 Technical Specifications ~Section 4.15.2.7.2.b and Unit 2 Technical Specifications section 4.11.2.7.2.b.

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TEXT CONTINUATION i f,ACILITY NAME (1) DOCKET NUMBER (2) LER NUMBER (5) PAGE (3)

VEAR SLO hum REV PI/Nr llATCil, UNIT 1 0500G321 90 024 00 3 or 6 IEXI The. review of the sample of Unit 1 and Unit 21990 data sheets showed samples were not collected and analyzed within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> of determining the release rate had increased by greater than 50% over the nominal steady state release rate.

For Unit 1, 24 days of data sere reviewed. On two of those days the release rate was more than 50% higher than the nominal steady-state value, yet no samples were collected and analyzed. For Unit 2, 31 days of data were reviewed. Again, on two of those days the release rate was mee than 50% higher than the nominal steady state value and no samples were collected and analyzed.

Af ter being notified by Safety Audit and Engineering Review personnel of this problem, plant Nuclear Safety and Compliance personnel expanded the review to include. Unit 1 and Unit 2 data sheets from'1988, 1989, and 1990. Approximately 718 days of Unit i data sheets were reviewed, representing over 60% of the data shoots completed for this 3-year period. It was determined one sample should have been collected and analyzed but was not. Similarly, approximately 687 days of Unit 2 data sheets were reviewed. This also represented over 60% of the data sheets completed for 1988, 1989, and 1990. It was determined five samples should have been collected and analyzed, but only two actually were, i The offgas sample is used to ensure the pretreatment monitor reading and setpoint accurately reflect the offgas activity. The pretreatment activity for those periods in which samples should have been collected and analyzed, but were not, was less than 50,000 uCi/second. This is less.than 21% of the Technical Specifications limit of 240,000 uC1/second. Furthermore, pretreatment gases were collected and analyzed routinely. Although these routine samples did not meet the requirements of Unit 1 Technical Specifications Section 4.15.2.7.2.b or Unit 2 Technical Specifications Section 4.11.2.7.2.b, they did help to ensure the pretreatment monitors were accurately reflecting the pretreatment activity levels. Therefore, it is highly unlikely any Technical-Specifications offgas pretreatment activity limits were exceeded.

CAUSE OF Tile EVENT The cause of this event was a misinterpretation of the Technical Specifications requirements. Contributing to the misinterpretation were ambigucus requirements concerning the nominal stet.dy state fission gas release value. Plant Chemistry

personnel felt the Specifications allowed them the ficxibility to recalculate the nominal steady-state value following a gradual increase in the activity level withNt first collecting ard analyzing a pretreatment sample. The Specifications do not address-how and when to calculate the nominal steady-state

.value or when it may be updated.

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TEXT CONTINUATION l F,ACILITY NAME (1) DOCKET NUMBER (2) Ll4 NUMBER (5) PAGE (3)

TEAR 5EQ hVM REV Pl#TT llATQl, UNIT 1 0500-0321 90 024 00 4 0F 6 I IEXT Chemistry personnel also felt the-Specifications all. owed them to factor out known causes such as changes in offgas system fica rate and moisture in the system which affect pretreatment activity levels. _The Specifications allow changes in activity Icvels caused by changes in thermal power to be factored out. It was felt this allowance could logically be extended to include other known factors which'might affect calculated activity levels. Consequently, samples were not collected and analyzed when pretreatment activity increased by greater than 50% over a nominal steady-state value when the increase was attributable to a known cause..

REPORTABILITY ANALYSIS AND SAFETY ASSESSMENT This report is required by 10 CFR 50.73(a)(2)(1) because a condition existed which was prohibited by the~ plant's Technical Specifications. Specifically, the requirements of Unit 1 Technical Specifications Section 4.15.2.7.2.b and Unit 2 Technical Specifications Section 4.11.2.7.2.b were not met. On at least eight occasions in the past 3 years, pretreatment gas samples were not collected and analyzed when the data showed an increase in activity levels of greater than 50%

over a nominal steady-state release value.

Noncondensible radioactive offgas is continuously removed from the main condenser by the air ejector during plant operation, The offgas is routed through the Offgas Recombiner Charcoal System (EIIS Code WF) where it is treated before release through the Main Stack. Radiation monitors are located before and after the charcoal adsorbers in the offgas system. They are known as the pretreatment monitor and the post-treatment monitor, respectively.

The protreatment monitor continuously monitors the input to the charcoal adsorbers. This monitor is used to provide an alarm on high radiation to assist-in ensuring. Technical Specification pretreatment activity limits are not exceeded. It displays an mR/ hour value. The Technical Specifications limit at the pretreatment monitor is-expressed in uC1/second, thus, the monitor reading must be converted from mR/ hour to uCi/second. This is done by calculating a conversion factor, called the k-factor, from a sample of the off 6 as to convert--

from mR/ hour to uCi/second for any given offgas flow expressed in cubic feet / minute.

. The k factor- serves two major purposes: it' allows a direct. reading from the' monitor to be readily converted to a value which can be compared to the Technical Specifications limit, and it allows the calculation of an alarm setpoint in mR/ hour equivalent to the limit of 240,000 uC1/second. The

'k-factor, however, is dependent on the mix of radioactive isotopes in the offgas. The mix is subject to change during large increases in offgas activity; therefore, the k factor is also subject to change under these conditions.

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TEXT CONTINUATION FACILITY NAME (1) DOCKET NUMBER (2) LER NUMBER (5) FAGE (3)

TEAR SEQ hum REW PLRTT llATW, UNIT 1 05000321 90 024 00 5 0F (,

TTu In order to ensure the k factor is current and correct and the pretreatment monitor reading and setpoint accurately reflect the offgas activity, the Technical Specifications require a gas sample to be collected and analyzed whenever there is a large increase in the pretreatment monitor reading. This is defined as an increase of greater than 50% as compared to a nominal steady state value. In the event described in this report, a gas sample was not collected and analyzed after every increase of greater than 50%. At least eight times in the last 3 years, activity increased by 50% over a nominal steady state value and no sampic was collected and analyzed.

It is highly unlikely, however, that Technical Specifications limits were violated as a result of this event. In all eight cases, pretreatment activity was less than 50,000 uCi/second. This is less than 21% of the limit of 240,000 uCi/second. The k factor would have to have been almost five times higher than the one in use at those times for the limit to have been unknowingly reached.

This could not have been the case because the k-factor is relatively stable at activity levels below approximately 100,000 uC1/second. In other words, increases in activity levels of 50% or more would not significantly affect the k-factor as long as the absolute activity level remained below approximately 100,000 uci/second.

Additionally, routine offgas samples were collected and analyzed. This was done about once per week. Any changes in the k-factor would have been noted when these samples were analyzed. While this did not meet the Technical Specification requirements, it did help ensure the k factor and, hence, the pretreatment monitor reading and alarm setpoint were current and correct. Since the increases in offgas activity levels, in general, were gradual and not step changes, the routine offgas samples provided a degree of confidence the pretreatment monitors were accurately reflecting the activity levels.

Based on the above discussion, it is concluded this event had no adverse effect on nuclear safety or public health and safety.

CORRECTIVF ACTIONS As an interim action, Chemistry personnel were instructed by their management to collect and analyze an offgas sample if the activity increases by 50% over the calculated nominal steady-state value regardless of the reason for the increase / difference. This was done by 1/8/91.

A Technical Specification Clarification will be issued per approved plant procedures by 1/31/91. The Clarification will resolve any ambiguities in the Specifications and provide clear instructions concerning implementation of the Specifications including how to calculate a nominal steady-state value, what to do with the results of the sample analysis, and when a new nominal vslue may be calculated and used.

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LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION r.ACILITY NAME (1) DOCKET NUMBER (2). LER NUMBER (5) PAGE (3)

YEAR SEQ huh REV PIAVI HATCH, UNIT 1 05000321 90 024 00 6 0F 6 TEu Appropriate Chemistry procedures will be reviewed and revised as needed to implement the Clarification. The procedures will be reviewed and any necessary revisions issued by 3/15/91.

ADDITIONAL INFORMATION No plant systems other than the offgas pretreatment monitor were affected by this event.

No failed components caused or resulted from this event.

Previous similar events in the last 2 years in which Technical Specifications required samples were not collected and/or analyzed in accordance with the Specifications were reported in the following LERs:

50 321/1989-002, dated 02/28/89 50 321/1989 013, dated 10/31/89 50 321/1990 009, dated 06/15/90 50 321/1990-023, dated 01/19/91 50 366/1989-001, dated 02/02/89 50-366/1989 003, dated 08/22/89 50-366/1990-011, dated 11/29/90 50 366/1990 013, dated 01/18/91 Corrective actions for these events could not have prevented this event because the root causes were different. The previous events were caused by inadequate procedures and/or personnel error whereas this event was caused by a misinterpretation of the sampling and analysis requirements.

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