ML20101U362

Forwards Summary of 920617 Meeting Between PSC & Co Dept of Health Water Quality Control Division & Radiation Control Division Re Effluent Releases During Decommissioning & Util Decommissioning Plans

ML20101U362
Person / Time
Site:	Fort Saint Vrain
Issue date:	07/14/1992
From:	Warembourg D PUBLIC SERVICE CO. OF COLORADO
To:	Weiss S NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation
References
P-92247, NUDOCS 9207220394
Download: ML20101U362 (36)

Text

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@ 16805 WCR 191/2; Platteville, Colorado 80651 Public Service'

=A July _14,1992

.1 Fort St. Vrain Unit No.1

.P-92247-U. S. Nuclear Regulatory Commission ATTN: Document Control Desk S

D. C, 20555

% jmour H. Weiss, Director A'IT t

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, awer Reactor, Decommissioning and o

. nmental Project Directorate

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SUMMARY

OF JUNE 17,1992 MEETING WITH STATE OF COIDRADO REGARDING EFFLUENT RELEASES DURING DECOMMISSIONING -

REFERENCE:

- PSC Letter, Warembourg to Director of NRR, dated April 30, 1992 (P-92181)'

Dear Dr. Weiss:

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Attached for your information is a summary of a meeting held on June 17, 1992, between Public Service Company of Colorado (PSC) and representatives of the Colorado Department of Health (CDH)_ Water Quality Control Division and Radiation Control

- Division.

This meeting was held to familiarize representatives of the CDH _with PSC's plans to decommission Fort St. Vrain (FSV), with particular emphasis on the release of tritium in liquid effluents.- The CDH Radiation Control Division has been involved in previous discussions involving FSV decommissioning plans,' and has regularly received copies of related _ correspondence with the NRC. The CDH Water Quality Control Division is currently in the process of renewing the FSV wastewater dischnrge permit, f

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.9207220394 920714 I

-PDR _ADOCK-05000267 P.

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P-92247 -

July 14,1992 Page 2 The attached meeting summary is provided in support of the FSV Environmental Report Supplement for Decommissioning, previously submitted via the referenced letter. The CDH administers Environmental Piotection Agency (EPA) programs and is responsible for surface water quality PSC described its plans to release tritium into downstream surface waters, where both the State standard and the EPA Safe Drinking Water Standard (40 CFR 141) limit tritium concentration to 20,000 pCi/1 PSC discussed its procedural controls and enhanced monitoring program for FSV decommissioning to ensure compliance with all applicable regulations. Sevaal items that were identified for further investigation will be resolved as part of the discharge permit renewal process, which is currently scheduled to be complete prior to flooding the PCRV with shield water.

The CDH participants in this meeting were provided with a copy of the attached meeting summary for review. The Water Qua!ity Control Division agreed with the summary as written and indicated that additional clarification may be requested from PSC on several issues. If you have any questions regarding the attached information, please contact Mr.

M. H. Holmes at (303) 620-1701.

Sincerely, _

dh d JY75unk Dona!d W. Warembourg Manager, Nuclear Operations DWW/SWC cc:

Regional Administrator, Region IV Mr. J. B. Baird Senior Resident Inspectar Fort St. Vrain Mr. Robert M. Quillin, Director Radiation Control Division Colorado Department of Health Ms. Pat Nelson Industrial Unit Chief Permits & Enforcement Division Colorado Department of Health

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51EETING SUh1 MARY This is a summary of the meeting held on June 17, 1992 between Public Service Company of Colorado (PSC) anci representatives of the Colorado Department of Health (CDH), Water Quality Control Divsion (WQCD) and Radiation Control Division (RCD).

Attendees were as follows:

Pat Nelson CDH, WQCD, Industrial Unit Chief Don Holmer CDH,WQCD Ken Weaver CDH, RCD Mike Nichoff PSC, Engineering Manager Mike Holmes PSC, Nuclear Licensing Manager Ted Borst FSC, Radittion Protection Manager Marty Deniston PSC, Operations Manager Terry Staley PSC, Nuclear Engineering Peter Cohlmia PSC, Unit Manager, Environmental Programs Dave Fetterolf PSC, Applied Sciences Jesse Brungardt PSC, Environmental Services Ed Parsons Westinghouse Scientific Ecology Group Jim Johnson Colorado State University Sam Chesnutt PSC, Nuclear Licensing Denotes those present for tour of effluent release path

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A copy of the meeting handouts / slides is attached.

Background

The purpose of the meeting was to familiarize representat ves of the Colorada i

Department of Health with PSC's plans te decommission Fort St. Vrain, with particular emphasis on the release of radioactive liquid effluents. Don Holmer and Pat Nelson of the CDH, WQCD are in the process of renewing the wastewater discharge permit for Fort St. Vrain. The renewal of this permit is being managed by PSC's Environmental Services organization, under Pete Cohlmia.

Ken Weaver of the CDH, RCD has historically been one of the State contacts for nuclear issues, and his office receives copies of all PSC correspondence with the NRC.

1

2 Meeting Overview PSC described their plans for dismantlement and decontarnination of the FSV Prestressed Concrete Reactor Vessel (PCRV). These plans include filling the internal cavity of the PCRV with shield water to provide shielding for decommissioning workers and reduce airborne contamination. Shield water will leach tritiu n from graphite ref!c r blocks, and this tritiated water will be released into the environment as liquid effluent.

PSC also described the liquid effluent release pathway and its commitment to ensure that releases are within the following limits:

Effluent concentrations in unrestricted areas will be within 10 CFR 20 Maximum Permissible Concentrations (MPCs),

Doses to individual members of the public will be within the limits of 10 CFR 50, Appendix I, and Concentrations of tritium in downstream surface waters and in ground water will be within the limits of the EPA Safe Drinking Water Standard in 40 CFR 141.

PSC indicated that its best estimate is that 500 curies of tritium will be released into the shield water.

This estimate is based on an activation analysis of internal core components and on graphite teach testing conducted by the British. PSC also stated that if the tritium released into the shield water is greater than this best estimate, they have established that up to 8000 curies of tritium could be released as liquid effluent over a period of about two years, within the above limitations.

PSC described the analyses p.rformed to assess the impacts on the general public from various potential radiological exposure pathways. These analyses are documented in the l

Environmental Report Supplement for Decommissioning and they demonstrate that PSC's plans are in compliance with the above limitations. PSC also discussed an enhanced monitoring program to demonstrate that downstream surface water tritium concentrations are within the EPA Safe Drinking Water Standard (20,000 pCi/1) and several possible sampling locations were discussed.

PSC described that the Offsite Dose Calculation Manual (ODCM) is the primary administrative control over effluent releases. The ODCM is currently being revised to reflect decommissioning requirements. PSC committed to ensure that the ODCM and the implementing procedures for the ODCM include: (1) these release concentration limits, (2) methods of calculating dilution flow requirements, (3) methods to account for river flow rates and upstream tritium concentrations to ensure that the downstream tritium concentration will be within the 20,000 pCill limitation, and (4) river sampling l

requirements, as needed to ensure and document compliance with each of the above limitations.

I

3 Discussion Much of the discussion centered around the methods of assuring that tritium concentrations in downstream surface water would be maintained below the EPA Safe Drinking Water Standard. PSC described its plans to base effluent release rates on river flows, so that the calculated concentration of tritium in the river would ha than 20,000 pCi/1, and to then perform downstream sampling to monitor for compno.ee. The CDH indicated that their normal practice is to assign a maximum release rate based on a 3-year minimum stream flow. The Environmental Report Supplement discussed typical release rates that would be possible with nominal (or average) river How rates. PSC agreed to provide the CDH with calculations that supported the discussions in the ER Supplement.

PSC conducted a tour of the liquid efnuent release path, from the point where diluted liquid effluent enters the Goosequill Ditch in the unrestricted area, along the Goosequill Ditch for about 8700 feet to the farm pond, and to the outlet of the farm pond. The tour also included the downstream sampling location that has been normally used during the FSV Radiological Environmental Enitoring Program. This location is readily accessible at a public bridge 5 miles downstream of the point where the farm pond outlet discharge enters the S. Platte River. This location has access to power for a continuous sampler.

The tour attendees were also shown alternate sample locations closer to the plant. These offer varying degrees of accessibility on a year round basis and various levels of mixing flows from the S. Platte River and St. Vrain Creek; however, they do not have good access to power. Dr. Johnson from CSU indicated that tritium does not plate out of the stream or deposit in river bottom sediments, so the 5-mile downstream sample location would provide representative, well-mixed river water samples. It was agreed that a continuous sampler would be better than taking grab samples. Both PSC and the CDH agreed to consider the relative merits and considerations involved with the various monitoring locations.

The CDH was also interested in other radionuclides that would be discharged as liquid effluent. They indicated that in addition to the NRC's authority for regulating radioactive effluent releases, there are State Standards on three radionuclides (these limits were later determined to be 20,000 pCi/l tritium, 30 pCill Cs-134, and 8 pCi/l Sr-90). PSC indicated that they only expect to see Co-60, Cs-137, and Fe-55, in addition to tritium.

The shield water system demineralizers will remove all radionuclides except tritium, to average concentration levels that are less than approximately 1 percent of the 10 CFR 20 Maximum Permissible Concentrations. PSC also discussed the ion exchange effect of clay sediments in the bottom of the ditches and the farm pond, that will further removt.

these radionuclides to negligible umounts. PSC agreed to provide estimates to the CDH of the range of concentrations of Co-60, Cs 137, and Fe-55 that are expected to be in the ligt.id waste holdup tanks prior to release. Noting that the concentrations in the liquid waste holdup tanks are prior to onsite dilution and would not be released to unrestricted

4 areas, PSC stated that these radionuclide concentration estimates should not be evaluated against drinkmg water standards. PSC also agreed to provide the distribution coefficient that describes the ion exchange phenomenon in clay ditch sediments.

The CDH indicated that the renewal of the FSV discharge permit was a priority project, and that a draft permit should be posted for comment by the fourth quarter of 1992.

This would be followed by a 30-day public comment period. The CDH also noted that the regulatory climate has changed since the last FSV permit was written. There is greater general interest in water discharge permits, and PSC should not be surprised if outside comments are received.

PSC indicated that certain chemical treatment processes would be used in '.he shield water, as biocides and corrosion inhibitors. PSC agreed to discuss these chemicals and

. th9 amounts expected to be used during decommissioning in a separate letter.

Several other topics diwussed included storm water discharge permits and sampling for l

PCBs. PSC stated that PCBs are net a problem at FSV and agreed to provide a one-time analysis of liquid effluent to confirm this fact.

At the conclusion of the meeting, PSC stated that they would prepare a set of minutes to document the meeting and that these minutes would be provided to the NRC, Ken Weaver agreed to contact Pete Erickson of the NRC and discuss the CDH review of FSV decommissioning plans, a

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4 EFFLUENT RELEASE REGULATIONS Liquid Effluent Will Be Released In Accordance With Regulations 10 CFR 20 Maximum Permissible Concentration (MPC) in Goosequill Ditch (3 G3 pCi/ml; 3 E-6 Ci/1; 3 E+6 pCi/l) 10 CFR 50 Appendix I dose limits for.aembers of the public (3 mrem / year; 1.5 mrem!qtr)

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EFFLUENT RELEASE PLANS i

PSC Plans to Release 500 Curies of Tritit. i Over About 200 Days, Based on Activation Analysis and British Test Data In Event Actual Tritium in Shield Water is Greater, PSC Could Release Up To 8000 Cuties of Tritiurn In Accordance With Above Regulations, Over About a 2 Year Period Release Will Be via Normal Effluent Release Pathway Rc! case Will Be Monitored By Enhanced Sampling and Analysis Program

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LIQUID EFFLUENT FLOWPATil Liquid Effluent is Released at Approximately 1.4 to 10 gpm This Release Water is Diluted By 1100 to 2000 gpm Blowdown Flow, To less Than 10 CFR 20 MPC (3 E 3 pCl/ml). This is Concentration in Goosequill Ditch and Farr,) Pond, to S. Platte River Release Point.

To Reduce Farm Pond Outlet Water to 20,000 pCi/l (2 E 5 pCi/ml) in Surface Water, a Dilution Factor of 150 is Required.

Nominal River Flow Downstream of Confluence of St. Vrain and S. Platte is 283,000 gpm. To Achieve Dilution Factor of 150, 1880 gpm Can Be Released via the Goosequill Ditch Effluent is Further Diluted in Ground Water (Gilcrest Town Water Supply). CS's calculations Indicate Tritium Concentrations Of Approximately 1000 pCi/l (1 E-6 pCi/ml).

EXPOSURE PATIIWAYS Drinking Water From Gilerest Town Water Supply at 1000 pCi/l Ingesting Garden Vegetables Irrigated With River Water at 20,000 pCi/l Ingesting Meat or Milk From Cows or Goats Pastured in Fields irrigated With River Water at 20,000 pCill Ingesting Watchwl From River Water at 20,000 pCi/l Ingesting Fish in River Water at 20,000 pCi/l l

DOSE CONSEQUENCES OF RELEASES Maximally Expmed Individual Would Receive:

0.54 mrem over 200 days of 500 Curie Release 0.99 mrem / year for 8000 Curie Release Integrav 1 Dose to Population Within 50 Miles:

1.2 person rem over 200 days of 500 Curie Release 2.8 person-rem / year for 8000 Curie Release Doset Are Within Regulatory Limits (3 mrem / year, 1.5 mrem /qtr)

Doses Are Less Than 9 person-rem / year Originally Evaluated in the Final Environmental Statement for Plant Operation A--

A_____-___.___________-_m.___

_______m

ADMINISTRATIVE CONTROLS ON RELEASES Releases Will Be Made in Accordance With Off Site Dose Calculation Manual (ODCM)

ODCM is Required By Plant Technical Specifications ODCM Will Require Calculation of Allowable Release Rate Based on:

Tritium Concentration in Release Water Dilution Flow in Goosequill Ditch River Flow in S. Platte River Upstream Tritium Concentration in S. Platte River s

. man

t ENIIANCED MONITORING PROGRAh!

During Tritium Releases, PSC/CSU Will Perform:

Weckly hionitoring of Continuous Sampler on Farm Pond Weekly hionitoring of Groundwater in Adjacent Farm Wells and in Gilcrest Water Supply Daily hionitoring of Surface Water in S. Platte River, Downstream and Upstream For First 3 hionths, Weekly Thereafter lacreased Goosequill Ditch Surveillance to Clear hioss and Debris

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