05000267/LER-1980-052, Forwards LER 80-052/01L-0

Forwards LER 80-052/01L-0

ML19347B657
Person / Time
Site:	Fort Saint Vrain
Issue date:	10/09/1980
From:	Warembourg D PUBLIC SERVICE CO. OF COLORADO
To:	Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML19347B658	List: 05000267/LER-1980-052, Forwards LER 80-052/01L-0 05000267/LER-1980-052-01, /01L-0:on 800925,found That Releases from Reactor Bldg Sump Following Releases from Radioactive Liquid Waste Sys Could Result in Excessive Radionuclide Concentrations. Caused by Capacity & Location of Oil Separator
References
P-80362, NUDOCS 8010150505
Download: ML19347B657 (8)

LER-1980-052, Forwards LER 80-052/01L-0

Event date:
Report date:
2671980052R00 - NRC Website

text

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PLATTEVILLE, COLOR ADO 80651 C

October 9, 1980 Fort St. Vrain Unit No.1 P-80362 Mr. Karl V. Seyfrit, Director Nuclear Regulatory Commist. ion 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

Dear Mr., Seyfrit:

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

80-52, Preliminary, submitted per che requirements of Technical Specifi-cation AC 7.5.2(a)9.

Also, please find enclosed one copy of the Licensee Event Report for Reportable Occurrence Report No. 50-267/80-52.

Very truly yours, W

Don Warembourg

/

Manager, Nuclear Production DN/cls Enclosure

~ cc: Director, MIPC 8'0101505

REPORT DATE:

October 9, 1980 REPORTABLE OCCURRENCE 80-52 De te rmined ISSUE O OCCURRENCE DATE:

Seotember 25, 1980 Page 1 of 7 FORT ST. VRAIN NUCLEAR GENERATING STATION PUBLIC SERVICE COMPANY OF COLORADO 16805 WELD COUNTY ROAD 191/2 PLATIEVILLE, COLORADO 80651 REPORT NO. 50-267 / 80-52/01-L-0 Preliminary IDENTIFICATION OF OCCURRENCE:

On Thursday, September 25,1980, at 0840 hours0.00972 days <br />0.233 hours <br />0.00139 weeks <br />3.1962e-4 months <br />, while the plant was in a scheduled shutdown condition, it was determined that due to the retention time of the oil separetor in the line concon to both the reactor building sump and the radioactive liquid waste effluent discharge system, releases from the reactor building sump following releases from the radioactive lig-uid waste system could potentially result in radionuclide concentrations in excess of the values specified in Table II, Column 2,10CFR20, Appendix 3, for unrestricted areas.

This is reportable per Fort St. Vrain Technical Specification AC 7.5.2(a)9.

CONDITIONS PRIOR TO OCCURRENCE:

The conditions prior to occurrence or at time of reportability determination are not applicable to this report.

DESCRIPTION OF GCCURRENCE:

During an analysis by plant personnel of the results of samples associated with a previous liquid waste release, it was determined that, due to the lo-cation and capacity of the oil separator in the line common to radioactive if quid waste and reactor building sump discharge, the possibility exists that under certain conditions liquid waste with a radionuclide concentration in excess of =aximum permissible concentration ('TC) as specified in Table II, Column 2,10CFR20, Appendix B could be discharged to the unrestricted area.

Refer to Figure 1.

Ef f' ents f rom the reactor building su=p ( A ) and the liquid waste system (

) are discharged to a common line ( C ) leading to the Goosequill Dite D

).

Circulating water blowdown ( E ) is ad-mitted for dilution purposes prior to the effluent raaching *Se,oosecuill Ditch. Radiation monitors RIS-6212 and RIS-6213 ( 1 and 2 ) in the com-

=en discharge line alarm at preset values on high activity in effluent dis-charged-f rom either the reactor building sump or the liquid waste system, an rovide a signal t; trip the liquid waste transfer pu=ps, close HV-6212

-(

) and, if the release is from the reactor building sump, close HV-7204-2,

(.

) thus terminating the release.

REPORTABLE OCCURRENCE 80-52 ISSUE O Page 2 of 7 DESCRIPTION OF OCCURRENCE:

(Cont'd)

Circulating water blowdown flow is monitored by a flow switch FSL-4101 ( 5 )

and at a preset value of low blowdown flow provides a signal to close HV-6.12, and to trip the liquid waste transfer pumps and reactor building sump pumps

((]$> on Figure 1).

Releases from the liquid waste system (System 62) are governed by the require-cents of Technical Specification LCO 4.8.2.

Prior to release, a maximum dis-I r

charge rate is established based on radionuclide concentrations in the liquid waste effluent. Based on the calculated release rate, it may be necessary to increase the. blowdown flow to greater than the nominal 1100 gpm to pro-r vide 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 monitors or to reduce the allowable release rate to assure that the discharge is within the specified limits.

Under normal conditions, discharge from 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 30 gpm with one reactor building sump pump in service) can be made provided the sump contents are prev 1ously l analyzed to assure compliance with CO 4.8.2 and

4. 8. 3.

Flow rate is. then increased by opening a bypass ( 6 ) in parallel j

with the radiaticn monitors. Under these conditions, a proportionate sample flow continues to pass through the radiation monitors to provide a means for termination of the release on high activity by closing HV-6212 and EV-s'04-2

,i and -directing the effluent to the liquid waste system via HV-7204-1 ( 7

).

J However, the ' design of *his system did not take.into account the effects of an oil separator ( 8 -) in the discharge line common to the reactor building sump and liquid waste discharge. The oil. separator has a capacity of approximately 3200 gallons; and, because the normal volume of a liquid waste release is in the range of 2200 to 2300 gallons, it is conceivable,

]

depending on mixing and dilution factors, that a good portion of the volume

. of a liquid waste release could be held up in the oil separator downstream of the monitoring equipment.

If a release from the reactor building ~ sump were initiated at an allevable higher

. flow rate following the liquid waste release postulated above, the volume of radioactive liquid retained in the oil separator would be mixed with the sung effluent and. subsequently discharged to the unrestricted area, v1rh possible radionuclide concentrations in excess of MPC.

j

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REPORTABLE OCCIRRENCE 80-52 l

ISSUE O l

Page 3 o f 7 l

APPARENT CAUSE OF OCCURRENCE:

Design The potential problem described in this report is a result of the holding capacity of the oil separator and its location in a line common to the lig-uid waste system and the reactor building sump.

l The initial request to the Nuclear Steam System Supplier '

installation

(

of the oil separator calltl for the separator to be instailed in the dis-l charge line of the reactor building sump pumps at e oint ahead of the tee at valves HV-7204-1 and HV-7204-2 (refer to point F o f Figure 1). The request also specified that the oil separator be provided with a drain bach to the sump and a bypass for use in draining if the sumo were called upon to handle radioactively contaminated water.

As can be seen frem the location of the oil separator on Figure 1, the above referenced design requests were not adhered to.

ANALYSIS OF OCCURRENCE:

In September,1970, Public Service Company of Colorado requested that the Nuclear S team System Supplier provide an oil separator in the discharge line from the reactor building sump pumps. It was assumed that the sump would accumulate oil due to its location below the Helium Circulator Handling Turntable and associated hydraulically driven equipment. Without an oil separator, any oil discharged f rom.the sump would be discharged either to the cooling tower blewdown or, if high activity were present, to the liquid waste system.

A subsequent inspection by the Environmental Protection Agency detected a quantity of oil in the ditch carrying water from the building drains. The concern over the possibility that the oil might have originated in the reactor building sump provided further substantiation of the need for an oil sepa-

rator, t

Because oil contamination of the liquid waste system would cause serious I

cleanup problems, Public Service Company requested that the oil separator be installed ahead of the tee at valves HV-7204-1 and HV-7204-2.

Installation at this point would have assured that oil would be removed from the sump effluent prior to. discharge either to the cooling tower blowdown or to the liquid waste system.

m d

REPORTABLE OCCURRENCE 80-32' ISSUE O

'! age 4 of 7 i

1 2

ANALYSIS OF OCCURRENCE (Cont' d) l Provision of ~the bypass requested by Public Service Company would have pre-cluded the possibility of radioactively contaminated water being held up in the oil separator. The lack of a bypass, as well as the inclusion of the separator in a line common to System 62 and System 72 provided a potential

_ for holdup of radioactively contaminated water and subsequent' discharge to i

che unrestricted area at rates in excess of those required to assure com-i pliance with Technical Specifications.

CORRECTIVE ~

1 ACTION:

Interim corrective action as a result of this situation is as follows:

1.

Procedure changes have been implemented to prescribe a release from

. the reactor building sump following a discharge fron the liquid waste system at the same flow rate prescribed for the System 62 release until approximately 6000 gallons of effluent are discharged through the oil separator to assure no releases in concentrations greater than MFC occur.

2.

Sampling and radiochemical analysis of cooling tower blowdown and

.farn pond effluent has been performed on a routine basis, with no releases-in excess of :!?C identified. The routine sampling pro-gram also includes sampling and analysis of liquid waste effluent before, during, and af ter each Liquid waste release.

In addition to the above sampling programs currently in effect, samples will be taken at the cooling tower blowdown diversion box at frequent intervals during the entire release to determine the adequacy of the procedure changes and the time at which the impact of the radio-active liquid effluent occurs at the diversion box.

3.

A design change action request has been submitted to the Nuclear Project Department to resolve the problem caused by the location of the oil separator.

The results will be included in a future supplemental report.

i l

FAILURE DATA /SIMILAR REPORTED OCCURRENCES:

None i.

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e REPORTA3LE OCCURRENCE 80-52 ISSUE O Page 5 of 7 PROGRASC!ATIC IMPACT:

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l REPORTA3LE OCCIPRENCE 80-52 ISSUE O Page 7 of 7 1

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Prepared By:

de h.2cI)

Cathy C/ Hirsch Technical Services Technician a

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Reviewed By:

[

,4y 7'e. Wf Chhm chnical Services Supervisor t

i Reviewed By:

Frank M. Mathie Operations !anager i

Approved By:

M gu _ L Don Warembourg g

Manager, Nuclear Produenon 4

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