Text

Forwards LER 80-067/01T-0
	ML19345A964
Person / Time
Site:	Fort Saint Vrain
Issue date:	11/20/1980
From:	Warembourg D; PUBLIC SERVICE CO. OF COLORADO
To:	Seyfrit K; NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML19345A965	List: ML19345A964; ML19345A969;
References
	P-80405, NUDOCS 8011250495
	Download: ML19345A964 (8)
	v • d • e

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-u l 16805 ROAD 19%

PLATTEVILLE, COLOR ADO 80651 i . e,

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l l Novembe r 20, 1980 [

Fort St. Vrain ;

, "! C.~1 Unit No. 1 i P-dO405 l

Mr. Karl V. Seyfrit, Director !

Nuclear Regulatory Comission

. Region IV Office of Inspection and Enforcement 611 Ryan Plaza Drive

, Suite 1000 Arlington, Texas 76012

]

Reference:

Facility Operating License

, No. DPR-34 Docket No. 50-267 1

Dear Mr. Seyfrit:

Enclosed please find a copy of Reportable Occurrence Report No. 50-267/

1 80-67, Preliminary, submitted per the requirements of Technical Specifi-

] cation AC 7.5.2(a)2.

) Also, please find enclosed one copy of the Licensee Event Report for Reportable Occurrence Report No. 50-267/S0-67. '

t Very truly yours, 1

$u Don Warembourg Manager, Nuclear Production l

DW/cis j

Enclosure ec: Director, MIPC l

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! S

/ / .

( 801125041 5

REPORT DATE: November 20, 1980 RE?CRTABLE OCCURRENCE 80-67 Determined ISSUE O OCCURRENCE DATE: November 7,1980 Page 1 of 7 FORT ST. 7 RAIN NUCLEAR GENERATING STATION PUBLIC SERVICE CCMPANY OF CCLORADO 16805 *.' ELD COU'ITY ROAD 19 1/2 PLATTEVILLE, COLCRADO 80651 REPORT NO. 50-267/80-67/01-T-0 Preliminary IDENTIFICATION OF OCCL"dRENCE :

On Friday, November 7,1980, at 0740 hours0.00856 days 0.206 hours 0.00122 weeks 2.8157e-4 months , it was determined that the con-centration of tritium in an unrestricted area following radioactive liquid release number 412, which was made on October 23, 1980, exceeded the limit specified in LCO 4.3.2(a) . At the ti=e of the occurrence, the plant was operating at less than 2*: thermal power.

Ihis event is reportable per Fort St. Vrain Technical Specification AC 7.5.2(a)2.

CONDITIONS PRIOR TO OCCL*RRENCE:

The conditions prior to occurrence or at the time of reportability deter-aination are not germane to this report.

DESCRIPTION CF OCCURRENCE :

During an analysis by plant personnel of the results of samples associated with radioactive liquid waste release nu=ber 412, it was determined that the concentration of tritium in an unrestricted area exceeded the limit specified in LCO 4.3.2(a).

Refer to Figure 1. Effluents from the reactor building sump ( A ) and the liquid waste system ( @S ) are discharged to a ec==on line ( C ) leading to the Goosequill Ditch ( @ ). Circulating water blowdown ( E ) is ad-mitted for dilution purposes prior to the effluent reaching ~he Goosequill Ditch.

Radiation noni: ors RIS-6212 and RIS-6213 ( @ and h ) in the com-mon discharge line alarm at preset values on high activity in ef fluent dis-charged from either the reactor building sumr or the liquid waste system and provide a signal rip :he liquid waste transfer pumps ( @ ), close HV-6212 ( , and -he release is f rom the reacter 1- tilding su=p, close MV-7204-2 ( ), thus terminating the release.

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REPORTABLE OCCURRENCE 80-67 '

! ISSUE O Page 2 of 7 i

. DESCRIPTION OF l OCCURRENCE: (Cont'd) :

I Circulating water blowdown flow is monitored by flow switch FSL-4101 ( C6 )

and at a preset value of low blowdown flev provides a signal to close HV-6212 and to trip the liquid waste transfer pumps and reactor building sump pumps

( (2) ) ([__a j> on Figure 1) . ,

? Under normal conditions, discharge f rom the reactor building sump (System 72)

} is at a flow rate less than or equal to 10 gpm. However, discharges at a

! rate in excess of 10 gpm (up to a maximum of approximately 50 gpm with one r reactor building sump pump in service) can be made, provided the su=p con-i' tents are previously analy:ed to assure compliance with LCO 4.3.2 and 4.3.3.

_ Flow rate is then increased by opening a bypass ( (}) ) in parallel with the radiation monitors. Under these conditions, a proportionate sample ficu con-tinues to pass through the radiation monitors to provide a means for termi-nation of the release on high activity by closing HV-6212 and HV-7204-2 and .

directing the effluent to the liquid waste system via HV-7204-1 ( 9 ).

Releases from the liquid waste system (System 62) are governed by the require-i ments of Technical Specification LCO 4.8.2. Prior to release, a maximum dis-charge rate is estaolished based on radionuclide concentrations in the liquid waste effluent. Based on the calculated release rate, it may be necessary to a increase the blowdown flow to greater than the nominal 1100 gpm to provide sufficient dilution to assure that radionuclides in concentrations greater than MPC are not released to unrestricted areas. It may also be necessary

}' to change the trip setpoints of the radiation monitora or to reduce the al-i levable release rate to assure that the discharge is within the specified 11=1ts.

However, the design of the liquid waste system did not take into account the effects of an oil separator ( (@) ) in the discharge line coc=en to the reactor building sump and liquid waste discharge system. The oil separator i

has a capacity of approx 1=ately 3200 gallons; the normal volume of a liquid !

waste release is in the range of 2200 to 2300 gallons. As detailed in Re-portable Occurrence 80-52, it is conceivable that a good portion of the volume of a liquid waste release could be held up in the oil separator down-4 s tream of the monitoring equipment.

j Furthermore, if a release f rom the reactor building su=p were to be made f ol-loving a liquid waste release at a release rate higher than that allowable for the liquid waste release, the radioactive liquid which had been held up in the oil separator would be released at an unacceptable release race.

This higher release race would result in a s= aller dilution f actor than originally calculated for the liquid waste release. This reduced dilution could result in discharges to the unrestricted area in excess of the allowable ,

j tadionuclide concentrations contained in LCO 4.S.2(a) .

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REPORTABLE OCCURRENCE 80-67 ISSUE 0 Page 3 of 7 DESCRIPTION OF OCCURR E' ICE : (Cont'd) :

In order to ensure against a possible violation of the limits of LCO 4.3.2(a) as a result of the above-rencioned circumstances, Deviation 180-445 to Sur-2 veillance Procedure SR 5.8.2be-it, " Radioactive Liquid Effluent System Instru-

, mentation Functional Test" was prepared and was subsequently approved by the Plant Operations Review Committee on October 10, 1980. This deviation calls for initiating a 6000 gallon release f rom the reactor building sump immediately after terminating a liquid waste release. (See corrective action 41 of R0 80-52.) The release rate from the sump is to be less than or equal to the release rate authorized f or the liquid waste release. This procedure has been f ollowed on liquid waste releases =ade subsequent to October 10.

In addition to the above flush of the oil separator, on October 21, 1980, an order was placed in the Health Physics Order Book calling for the collection 2

of cooling tower blowdown samples once per two hours during the last half of the liquid waste release and f or the entire duration of the reactor building sump release (see corrective action #2 of RO 80-52) .

Liquid waste release number 412 was initiated at 1730 hours0.02 days 0.481 hours 0.00286 weeks 6.58265e-4 months on Oc tober 22, 1980, and secured at 0623 hours0.00721 days 0.173 hours 0.00103 weeks 2.370515e-4 months on October 23, 1980. The reco= mended release rate was 3.0 gps, with a cooling tower blowdown (dilution) rate of 2300 gps.

Subsequent analysis indicated a calculated release race of 2.6 gpm and a calculated blowdown rate of 2733 gpm. Due to an apparent clog in the reactor building su=p discharge line, the flush was not begun until approx 1matelv 1645 hours0.019 days 0.457 hours 0.00272 weeks 6.259225e-4 months on October 23, and was secured at 1300 hours0.015 days 0.361 hours 0.00215 weeks 4.9465e-4 months on October 24. The reactor building sump flow rate was adjusted by operations personnel so tSct the sump flow rate recorder, FR-7216, read approxt=ately 3 gpm. Subsequent to the oil separator flush, an analysis of the reactor building sump flow integrator, FIQ-7215, indicated that the flush had been performed at an average release rate of 4.3 g;m,1.8 gpm greater than the recommended re-lease rate.

Health Physics personnel collected liquid samples, per the Health Physics Order, during the liquid waste release and subsequent flush. Subsequent analysis of the sample taken at 1800 hours0.0208 days 0.5 hours 0.00298 weeks 6.849e-4 months on October 23 indicated a tritium concentration in the unrestricted area of 3.23E-3 C1/cc. The limiting con-centration of tritium per LCO 4.3.2(a) is 3.00E-3 Ci/cc in the unrestricted area. Results of samples taken prior to and subsequent to the 1300 hours0.015 days 0.361 hours 0.00215 weeks 4.9465e-4 months sample indicated tritium concentrations within the limit of LCO 4.S.2(a).

It should be noted that the saaple indicating a concentration of tritium ex-ceeding the limit of LCO 4.S.2(a) was taken from the Goosequill Ditch, con-sidered to be in the unrestricted area although located on Public Service Company of Colorado property. Thc Goosequill Ditch flows into a 25 acre farm pond, also on Company property, the overflow of which drains into the South Platte River. The additional dilution provided by the pond enaures that the concentration of liquid flowing into the South Platte River is with-in the limits of LCO 4.S.2(a).

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REPORTABLEOCCUkRENCE80-67 ISSUE O j Page 4 of 7 3

APPARENT CAUSE l OF OCCURRENCE: ;

, 1 Deviation 80-445 to SR 5.8.2bc-M was inadequate as written to avoid problems arising from the design of the reactor building sump discharge system.

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! ANALYSIS OF OCCURRE' ICE:

Deviation 80-445 to Surveillance Procedure Number SR 5.3.2bc-M was written to address the concerns raised in Reportable Occurrence RO 80-52 with respect

to the possibility of exceeding the limits of LCO 4.3.2(a), concentrations of l radioactive liquid in an unrestricted area. The deviation calls for a 6000 gallon flush of the oil separator in the discharge line common to the ,

reacter building sump and liquid waste discharge systems, following a radi- !

onceive liquid waste release, at a rate Icss than or equal to the recommended

liquid waste release rate. '

Following liquid waste release number 412, operations personnel. correctly i i

' followed the requirements of SR 3.3.2bc-M and lef t HV-6212 ( C4 ) in the open position. Upon initiation of the reactor building sump release, oper-ations personnel agcin correctly followed SR 5.8.2be-M and attempted to con-trol the release rate by throttling the controller for EV-6212 HC-6212,

located on the 4771' elevation of the Reactor Building, by hand, while a Re-actor Operator in the Control Room observed the flow rate meter FR-6217.

( FR-6217 is a linear flow rate recorder with a range of 0 - 125 gpm, in,cre-

! mented by 2.5 gpm. Accurate confirmation of a small (less than 5 gpm) re-lease rate using FR-6217 is not possible. This inability to accurately es-

cablish the 3.0 gpm allowable release rate from the reactor building sump contributed to exceeding the limit of LCO 4.3.2(a).

I Another problem area involves the possibility of obstructions in the reactor

! building sump discharge system, as noted under the " Description of Occurrence" 3

Portion of this report. It is possible that the sump flow rate could be es-tablished while an obstruction existed in the discharge line. Subsequently,

the obstruction could clear itself, resulting in a higher than allowable dis-

charge race.

p A Design Change Action Request has been submitted to the Nuclear Project

. Department proposing a bypass line around ;he oil separator, but has not received final approval (see corrective action 9 3 of Reportable occur-rence R0 30-52).

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REPORTA3LE OCCURRENCE 80-67 ISSUE O Page 5 of 7 CORRECTIVE ACTION:

Interin corrective action taken irriediately upon discovery of the occurrence involved an informal change to SR 5.8.2bc 't, calling for the Reactor Operators to establish the reactor building sump flow rate using su=p flow integrator FIQ-6216 and periodically evaluate the flow rate and adjust as necessary to ensure an acceptable flow rate from the sump.

Station Management is assessing possible additional corrective action. The results of this review will be reported in a supplemental report.

FAILURE DATA /SD11LAR REPORTED OCCURRENCES:

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1 REPORTABLE OCCURRE' ICE 80-67 I5 SUE O l Page 7 of 7 l Prepared By: J S4 A > ','-

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Frederick J. Sorstj 3enior Plant Engineer Reviewed By: / . sw gd.W.Gahm v Technical Services Supervisor Revteued By: D. /Y) />]JC [L ;Qyyyy Frank !!. !La thie v/

Operations Manager Approved 3y: / Mwdw Don Warenbourg ,f Manager, :uclear Preduction

ML19345A964

Text

Reference:

Dear Mr. Seyfrit:

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