ML20204G230

Rev 4 to PGE-1063, Suppl to Applicants Environ Rept - Post Operating License Stage

ML20204G230
Person / Time
Site:	Trojan File:Portland General Electric icon.png
Issue date:	03/18/1999
From:	PORTLAND GENERAL ELECTRIC CO.
To:
Shared Package
ML20204G184	List: ML20204G178 ML20204G230
References
PGE-1063, PGE-1063-R04, PGE-1063-R4, NUDOCS 9903260111
Download: ML20204G230 (20)

Text

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i Portland General Electric Supplement to Applicant's Environmental f Report i-4

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s Post Operating License Stage Trojan Nuclear Power Station Revision 4 Q "

9903260111 990318 PDR ADOCK 05000344 W PM

L Table of Contents 1 Introduction and Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 l 2 Plant Site and Surrounding Areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 2.1 Location of the Plant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 2.2 Description of Plant Site . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 2.3 Human Activities in the Environs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.4 Geology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . , , , , , , , , y g 2.5 Hydrology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 l 1

2.6 Meteorology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 2.7 B i ota . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 2.8 Other Environmental Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 3 Deco m missioning Pla ns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 3.1 Selection of Decommissioning Alternative . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 3.2 Decommissioning Schedule . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 3.3 Interim Operation in Permanently Defueled Status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 3.4 Plant Dismantlement Activities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 4 Environmental Effects of Decommissioning Activities . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 4.1 Effects on Human Activities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 4.2 Effects on Terrain, Vegetation and Wildlife . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 l 4.3 Effects on Adjacent Waters and Aquatic Life . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 i

! 4.4 Effects of Released Radioactive Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 t

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~ 4.5 Effects of Released Chemical and Sanitary Wastes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 l 1

i 4.6 Radioactive Waste . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 l l

1 4.7 Other Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 l 4.8 Summary of Environmental Effects of Decommissioning Activities . . . . . . . . . . . . . . . . . 24 5 Environmental Effects of Accidents and Decommissioning Events . . . . . . . . . . . . . . . . 25  !

5.1 Radioactive Release from a L' bsystem or Component . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 5.2 Fuel Handling Accidents Outside Contaiment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 5.3 Loss of Spent Fuel Heat Removal Capability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 5.4 Decommissioning Events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 6 Environmental Monitoring Activities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 6.1 Final Radiation Survey and Release Criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 O '6.2 Environmental Radiological Surveillance Plan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . , . 29

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7 Environ mental Approvals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 7.1 Federal Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 7.2 Stnte and Local Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 1

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List of Tables and Figures Tables: )

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Table 2.3-1 Population of Cities Within a 50-Mile Radius of Trojan Site - 2000 Population and l Over Table 2.3-2 Agricultural Land Use in Columbia and Cowlitz Counties Table 2.3-3 1993 Land Use Census Table 6.1-1 (Deleted) l l

l Figures:

l Figure 2.2-1. Site Location Figure 2.2-2 Site and Exclusion Area Figure 2.3-1 1990 Population Distribution Within 10 Miles Figure 2.3-2 2000 Projected Population Distribution Within 10 Miles Figure 2.3-3 2010 Projected Population Distribution Within 10 Miles Figure 2.4-1 Geologic Map Figure 2.4-2 Site Geologic Sections Figure 2.4-3 Geologic Section l

l Figure 2.5-1 Surface Hydrology Figure 2.5-2 Ground Water Table Contours Figure 2.5-3 Geologic Section Through Trojan Site Showing Piezometric Section I

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List of ENective Pages ,

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j Page Number Revision l Title page March 1999 Executive Sumary Original

il through v March 1999 I through 3. Original 1

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Figure 2.2-1 and 2.2 2 Original i

I j 4 through 9 Original l 1 Figure 2.3-1 through 2.3-3 Original i

j 10 and 11 Original i Figure 2.4-1 through 2.4-3 Original 4

12 through 14 Original Figure 2.5-1 through 2.5-3 Original f 15 Original

.! 16 and 17 September 1996 e

i 18 November 1996 i

i Figure 3.2-1 . November 1996

. 19 through 33 March 1999 y ., Revision 4

ENVIRONMENTAL REPORTSUPPLEMENT. POST OPERA TING LICENSE STAGE 3.3 Interim Operation in Permanently Defueled Status The' spent ful is currently stored in the spent fuel storage pool at the Trojan site. Operation of

. the spent fuel pool is currently governed by the provisions of the Trojan Technical Specifications.

It is planned to relocate the spent nuclear fuel currently stored in the Spent Fuel Pool to an Independent Spent Fuel Storage Installation (ISFSI). This is technically not a decommissioning activity. It is discussed in this section because it is an integral part of the decommissioning option selected. Use of an ISFSI has been determined to be the most economical method for temporary storage of the spent nuclear fuel until a federal repository is available. The specific ISFSI design that will be used at Trojan has not yet been selected. Howcr x, typically such an installation provides for the storage of a concrete vault, steel canister, or concrete canister.

10 CFR Part 72 specifies the requirements, procedures, and criteria for issuance of a license associated with an ISFSI. Current plans provide for licensing and constructing an ISFSI with relocation of the spent nuclear fuel and high level radioactive waste to the ISFSI to be completed -

by mid-1998.

While the spent nuclear fuel is stored in the Spent Fuel Pool, only limited decommissioning activities will be conducted, and any activity with a potential adverse affect on the safe storage of spent nuclear fuel will be prohibited. ' Some additional component removal and disposal activities may take place during this time. Following relocation of the spent nuclear fuel to the ISFSI, decontamination and dismantlement of structures, systems and components throughout

/~ the facility may proceed with no adverse impact on the safe storage of the spent nuclear fuel.

O} 3.4 Plant Dismantiement Activities During the decontamination and dismantlement phase, contaminated systems will be removed, packaged, and shipped to a low-level radioactive waste disposal facility. Decontamination of plant structures is expected to be completed concurrently with the equipment and system removal process. Structure decontamination will include a variety of techniques, ranging from washing to selective removal of contaminated concrete. Although not required for termination of the 10 CFR Part 50 license, some removal and disposal of hazardous / industrial waste materials, such as asbestos, may take place while decontamination and dismantlement are occurring. Hazardous materials will be handled and disposed ofin accordance with applicable state and Federal regulations. It is anticipated that some building demolition may atro occur during this time.

These activities are scheduled to begin in mid-1998, after relocation of spent nuclear fuel to the ISFSI, and continue through 2001.

During the decontamination activities, remediation control radiological surveys will be performed to monitor the effectiveness of the decontamination efforts. As the decontamination phase is ending, a detailed plan for the final radiological survey will be developed as described in Section 6.1. l

] The purpose'of this survey is to determine the final condition of the site and to support the i request for termination of the 10 CFR Part 50 license. This survey will document that the j radiological conditions are within the previously established limits. l 19 Revision 4 i

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i ENY1RONMENTAL REPORTSUPPLEMENT- POST OPERA TING UCENSE STAGE '

4 Environmental Effects of Decommissioning Activities 4.1 Effects on Human Activities l

• Approximately 140 acres of the site are currently set aside for recreational uses. Included in this I is a 28-acre recreational lake. Picnic areas, hiking and bicycle paths, and parking facilities are

, provided in this area.

I The site is in an area that has experienced construction of several large industrial facilities in addition to the construction of Trojan. There are the facilities required to accommodate many additional temporary workers that may be required for decommissioning activities. The number of workers is expected to be less than the number typically employed during a refueling and i

maintenance outage. Some skilled workers live in the nearby communities of Longview, Kelso, i Rainier and St. Helens. Most of those who come from Portland - the largest source of skilled j

craft labor - prefer to commute rather than relocate. There are no significant adverse impacts

. expected on temporary housing or schcols as a result of the decommissioning activities.

Property taxes from the operation of Trojan have had a positive impact on the area surrounding l the plant. The combined consolidated levies oflocal property tax is approximately $2.9 million

per year. The local property tax revenues may be significantly reduced as a result of the shutdown and decommissioning of Trojan.

! 4.2 Ettects on Terrain, Vegetadon and Wildlife k The decommissioning' activities will take place on the previously developed areas of the plant i

J site. Those areas of the site which have been left in their natural state will not be disturbed by activities required for decommissioning. Thus there will be no effect on the existing terrain or

} vegetation in the undeveloped areas of the site.

Waterfowl will not be materially affected by decommissioning activities.. The whistimg swans are sufficiently distant from the site of decommissioning activities that they will experience no i

discernible effect. Ducks and shore birds located in the reflection and recreation lakes will also be unaffected by decommissioning activities.

i 4.3 Effects on Adjacent Waters and Aquatic Life Decommissioning activities will not require any construction activities on the Columbia River i

shore line or river bottom. A barge-unloading area was constructed at the site during initial plant construction and will be used during decommissioning for shipment of certain large components.

l Neer Creek, a small stream flowing into and through the recreation lake, will not be materially disturbed by decommissioning activities. Given that the decommissioning work will be done in the developed areas of the site, the lakes on the site and the aquatic life therein will not be adversely affe ted by decommissioning activities.

4.4 Effects of Released Radioactive Materials Gaseous Radioactive Effluents Production of gaseous radioactive waste at Trojan ceased when the facility was permanently shutdown. Since that time radioactive gasses that resided in the gaseous radioactive waste O processing system have been processed and released in accordance with the restrictions 20 Revision 4

l ENVIRONMENTAL REPORTSUPPLEMENT- POST OPERA TING IJCENSESTAGE \

facility operating license. Decommissioning and dismantlement activities will not generate or D l result in the release of additional gaseous radioactive nuerials and the installed gaseoa

( radioactive waste treatment system will not be used during the decommissioning activities.

l Radioactive airbome particulate matter will be generated during some dismantlement activities.

HEPA filtration systems in plant building exhaust ventilation will be used to limit the release of l l

such airbome particulates. Temporary ventilation and filtration systems may be used to replace  !

or supplement the installed plant systems to minimize the spread of radioactive particulate contamination. Minor gaseous activity continues to be released from the spent fuel (Kr-85 l escaping from micropores in the fuel cladding) and spent fuel pool (tritium released during spent fuel pool evaporation). Plant procedures will control the monitoring, sampling and release of gaseous radioactive effluents during decommissioning activities. l l

Liauid Radioactive Effluents Decontamination processes, cutting operations and draining ofplant systems during decommissioning will generate additional liquid radioactive waste. Portions of the existing liquid radioactive waste treatment system will be used to process this waste prior to release.

Additional temporary waste water processing systems may also be utilized during decommissioning. Plant procedures will control the monitoring, sampling and release ofliquid radioactive effluents during decommissioning activities.

The methodology and parameters used in the calculation of offsite doses resulting from radioactive gaseous and liquid effluents, in the calculation of gaseous and liquid effluent -

fm monitoring alarm and trip setpoints, and in the conduct of the Radiological Environmental (j Monitoring Program are contained in the Offsite Dose Calculation Manual (ODCM). The ODCM also contains the Radioactive Efflent Controls Program and the Radiological Envirorunental Monitoring Program.

4.5 Effects of Released Chemical and Sanitary Wastes During operation of the Trojan plant, water from the Columbia River was used to provide makeup to the natural draft cooling tower and to provide cooling for plant equipment. Some chemicals were used in the plant's once through cooling system and in the water recirculated through the plant cooling tower to prevent the buildup of scale, corrosion deposits, sediment and organic growth. These chemicals included sulfuric acid to overcome the scaling properties of the river water; chorine to eliminate biological fouling and sodium bisulfite to eliminate residual chlorine in water prior to its return to the river. The use of these chemicals was controlled to minimize any impact on the quality of the water retumed to the Columbia River. Discharges to the Columbia River were made in accordance with the limitations and conditions in the National Pollutant Discharge Elimination System (NPDES) Waste Discharge Permit issued to the plant.

With the permanent shutdown of the Trojan plant, the circulating water system and cooling tower are no longer used and blowdown flow from this system is no longer discharged to the Columbia River. This has eliminated the discharge of small quantities of Nacl and NaHSO 3that resulted from the elimination of residual chlorine in the blowdown by the addition of sodium bisulfite.

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ENYlRONMENTAL REPORTSUPPLEMENT- POST OPERA TING LICENSE STAGE The plant's Service Water System remains in service to provide makeup water for the spent fuel l f '

storage pool. The shutdown of the plant has greatly reduced the demand for water from this system. Chlorination of this system (and the neutralization of the residual chlorine) will be l  ;

performed as needed. The impact of this chlorination on the water discharged to the Columbia l River is reduced from previous levels, however, due to the reduced flow requirements and the l elimination of regular periodic chlorination. '

l Discharges originating from blowdown of the reactor coolant system and miscellaneous steam leaks and drains from the plant secondary system have also been eliminated as a result of the permanent shutdown of the plant.

With the plant permanently defueled, the water use is less than when the plant was operating.

Water is drawn from two wells on site and the Columbia River. The estimated maximum usage j

from the wells is 26,925 gpd for potable water and for the demineralized water system, with l'

plans to use an additional 43,200 gpd for potable water, backup fire protection, and air compressor bearing cooling water. The estimated maximum plant usage from the Columbia River is 42,600 gpm (40,000 gpm for the service water system,2,000 gpm for the fire system, and 600 gpm for the screen wash system).

The daily average minimum flow of the Columbia River at Trojan is approximately 120,000 cubic feet per second. The discharge is at the bottom of the river in a manner providing an

average 120-fold dilution by the time the effluent reaches the river surface. Further dilution of the discharge occurs rapidly in the river. Within 12,000 feet of the discharge, complete mixing is

! expected.

The original Trojan environmental report noted that chemicals from the plant, aner dilution by river water, would cause only a slight increase in the concentration ofelements and compounds which already existed in the river. The report concluded that the waste discharge from the Trojan plant would have a negligible effect on the chemical composition of the Rainier drinking water and cause no adverse effects on human health from this source. The report also concluded that chemical wastes from Trojan would have a negligible biological impact on the environment of the Columbia River or on the area surrounding the plant. These conclusions have subsequently 1 been supported by the continuing monitoring of the environment in the vicinity of Trojan. The permanent shutdown of Trojan has further reduced any chemical discharges from the levels that resulted from plant operation. Any chemical discharges resulting from decommissioning activities will be made in accordance with the limitations and conditions of the NPDES Waste Discharge Permit issued to the plant.

l During plant operatior various chemicals were also present in the cooling tower driR. These consisted basically ofinsoluble salts. Chlorine was also present in the cooling tower dria within the cooling tower structure. An asbestos cement material was used for constmetion of po:tions of the cooling tower internals. As stated in the original Trojan environmental report, there'were

no measurable environmental effects expected due to operation of the cooling tower. However, since the cessation of plant operations, the cooling tower is no longer in use and release of any chemicals contained in the cooling tower drin has also ceased.

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ENVIRONMENTAL REPORTSUPPLEMLVT- POST OPERA TING LICENSE STAGE The Trojan sewage waste treatment plant collects drainage of sanitary waste from various site

/O , facilities as well as the recreation park. A sequential batch wastewater treatment plant was V placed into service in November 1989. This plant is rated at 75,000 gallons per day. It replaced a 25,000 gallon per day extended aeration treatment facility which has subsequently been dismantled. The new facility provides wastewater treatment through batch reaction in an aerated mixed liquor media followed with solids removal by settling and disaffection with hypoclorite prior to discharge. This plant has sufficient capacity to accommodate the expected work force that will be required during dismantling activities. The size of the expected work force is

[ expected to be less than the number typically employed during a refueling and maintenance outage.

4.6 Radioactive Waste 4

Radiation exposure to members of the public due to decommissioning activities will be limited to the direct radiation exposure associated with the shipment oflow-level radioactive waste for burial. NUREG-0586 estimates this radiation exposure to total 20.6 person-rem. The estimetM cumulative radiation exposure to the public is the sum of the small individual radiation exposures that are assumed to occur when members of the public are in the vicinity of a low-level radioactive waste shipment (truck) for brief periods. The packaging and amount ofradioactive

, waste in each shipment is restricted by NRC regulations (10 CFR 71) and Department of Transportation (DOT) regulations (49 CFR 170-189).

4 The NUREG-0586 estimate for radiation exposure to the public was based on the shipment of an estimated volume of 18,340 m3 oflow-level radioactive waste for burial. The current estimate of the volume oflow-level radioactive waste to be shipped from the Trojan site for burial is 2

312,558 ft' or 8,849 m , The currently estimated low-level radioactive waste shipments from the

Trojan facility are well within the bounds of the waste shipment volume estimated in NUREG-0586. The steam generators and pressurizer comprise approximately 1069 m' of this total. The current decommissioning plan calls for shipment of the steam generators via barge on the Columbia River from the Trojan site to a point near the final burial site. Since the number of members of the public who would be in the proximity of such shipments would be significantly less than that associated with transportation by truck, this will result in even lower levels of  !

i public exposure than those assumed in NUREG-0586. The cumulative radiation exposure to the public is expected to be within the bounds of those previously estimated by the NRC, and the low levels of radiation exposure associated with individual low-level radioactive waste shipments will be limited in compliance with NRC and DOT regulations.

4.7 OtherEffects The total estimated occupational radiation exposure associated with the planned decommissioning activities at the Trojan facility is 591 person-rem. This is well within the bounds of the estimated total occupational exposure of 1,115 person rem contained in the NRC's generic environmental impact statement. The estimated occupational radiation exposure is also within the NRC's revised estimate of 931 person-rem contained in NUREG/CR-5884, " Revised Analyses of Decommissioning for the Reference Pressurized Water Reactor Power Station." The occupational radiation dose to any individual worker will be limited by federal regulations and Trojan administrative procedures. The NRC published a revision to its occupational radiation 23 Revision 4

ENVIRONMENTAL REPORTSUPPLEMENT- POST OPERA TING LICENSE STAGE protection regulations in 1991. These revised federal regulations, which became effective on O January 1,1994, contain strict limitwn the amount of radiation exposure to individual workers at nuclear power plants. These regulations, in combination with Trojan administrative procedures, will also be applicable during decommissioning activities. The emnulative occupational radiation dose associated with decommissioning activities for facilities such as Trojan has been evaluated and found to be acceptable and the radiation doses to individuals will be in compliance with the latest federal regulations and Trojan administrative procedures.

Transmission lines in the vicinity of the Trojan site will be unaffected by decommissioning activities.

A natural area cbmprises about half of the total site area. This area consist of most of the river's edge (tPling about 3/4 of a mile), portions of the riparian woodlands and hardwood forest, hills and bluirs r + the west edge of the site, and former agricultural and wetlands in the north central portion of the site. These areas will not be adversely affected by decommissioning activities.

Tne site is located in a 634-acre area remote from either commercial or residential construction.

Bounded by the Columbia River on the east and U. S. Highway 30 on the west. During initial plant construction, the normal construction noise had no measurable effect on the environment.

No effect was discemed on the whistling swans or on the ducks and shore birds using the reflection and recreation lake as a habitat. Sound levels during decommissioning activities are

, not expected to exceed those that were present during initial plant construction.

4.8 Summary of Environmental Effects of Decommissioning Activities The original environmental report for Trojan demonstrated that the construction and operation of the Trojan plant would result in no unacceptable effects on the environment. The change in the environmental impact due to decommissioning of Trojan is generally favorable. In most cases,  ;

decommissioning eliminates or further reduces the already small environmental effects that have been associated with operation of the facility. There are certain environmental effects which will be increased due to decommissioning activities. These include the occupational radiation <

exposure necessary for decommissioning activities, the radiation exposure to the public associated with transportation oflow-level radioactive waste, and the commitment of small amounts ofland at the burial site for disposal of this low-level radioactive waste. However, these estimated effects for the proposed Trojan decommissioning are well within those which have been previously evaluated by the NRC on a generic basis. Therefore, the proposed decommissioning of the Trojan facility will have no unacceptable impacts on the environment.

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ENVIRONMENTAL REPORTSUPPLEMENT- POST OPERA TING LICENSE STAGE 5 Environmental Effects of Accidents and Decommissioning Events The original Trojan environmental report evaluated the environmental impact of postulated accidents and occurrences, however remote, that could occur during the operating life of the Trojan Nuclear Plant. The evaluation followed the guidelines given in the AEC document " Scope of Applicants' Environmental Reports with Respect to Transportation, Transmission Lines, and ,

Accidents" issued on September 1,1971. The results of that evaluation concluded that the consequences of the postulated accidents and occurrences would have no significant adverse environmental effects.

With the cessation ofpower operation of the Trojan reactor and removal of the nuclear fuel from the reactor vessel, most of these postulated accidents are no longer possible. For the few accidents which remain applicable, the consequences are significantly less than were postulated during plant operation. This is the result of radioactive decay of the spent iael and other radioactive materials which has occurred and continues to occur since the end of plant operations. PGE prept.wi a revised safety analysis report to specifically addmss those accidents which remain applicable in the permanently defueled condition. This analyses, "Defueled Safety Analysis Report" (DSAR), was submitted to the NRC on October 7,1993. The results of potential accidents evaluated in the DSAR are described in the following sections. These potential accidents include a) radioactive release from a subsystem or component, b) fuel i handling accidents, and c) loss of spent fuel decay removal capability.

As concludal in the initial environmental report, the potential environmental impact remains insignificant and inconsequential and the maximum man-rem realistically established as a msult of any accident is well within the increment of exposure to the general public corresponding to variations in natural background.

The decommissioning plan includes the anJysis of events which could be postulated to occur during decommissioning activities and which could result in the release of radioactive materials.

These events are described in Section 5.4 5.1 Radioactive Release from a Subsystem or Component The reactor coolant system and secondary system are no longer operated at elevated temperature or pressure. Therefore, releases to the environment from these systems were not considered.

During plant operation, the Waste Gas Decay Tank (WGDT) permitted the decay of accumulated radioactive gases prior to their release as a means of reducing the normal release of radioactive materials to the atmosphere. The principal contents of the WGDT were noble gases krypton and xenon generated from fission, the particulate daughters of the krypton and xenon isotopes, and trace quantities of halogens. These noble gases are no longer generated at the Trojan facility and the WGDT has been vented. Therefore, a rupture of the WGDT is no longer a possible accident for Trojan.

Postulated releases due to a liquid tank failure were considered. A postulated release of the contents of a Chemical and Volume Control System (CVCS) holdup tank was evaluated. This tank has the highest potential atmospheric release source due to its large volume. The tank was O, conservatively assumed to contain reactor coolant that had decayed for 40 week 25 Revision 4

4 ENVIRONMENTAL REPORTSUPPLEMENT- POST OPERA TING llCENSE STAGE operation of the Trojan facility. This conservatively bounds any liquid releases that could occur during defueled operations or decommissioning activities.

DSAR analyses concluded that the potential radioactive releases from a subsyster. ar component are conservatively bounded by the results of a postulated fuel handling accident discussed in the following section.

5.2 FuelHandling Accidents Outside Containment The possibility of a spent fuel handling accident is very remote due to the administrative controls and physical limitations imposed on fuel handling operations. However, a spent fuel assembly is a significant source of radioactive material and possible accidents involving spent fuel assembly damage was evaluated in the DSAR. Due to radioactive decay of the spent fuel, the potential consequences of such a postulated event are less that those previously calculated to occur during power operation. Although more than two years have elapsed since the end ofpower operations at Trojan, the DSAR analyses conservatively assumed a decay time of six months.

The results of the DSAR analyses indicate the potential radiation dose to at individual at the exclusion area boundary am an extremely small fraction of the 10 CFR 100 limits and are well below the EPA Early Phase Protective Action Guideline (PAG) levels.'

5.3 Loss of Spent Fuel Heat Reinoval Capability The spent fuel pool (SFP) and SFP cooling system are designed to maintain the SFP temperature at or below 140 F. The SFP is also designed to maintain fuel cladding integrity in the event that i forced cooling is lost. In the event that forced cooling is lost, cooling occurs by boiling at the surface of the SFP with evaporative losses being made up by a supply of makeup water.

The DSAR evaluated a number of scenarios, including the loss of SFP forced cooling concurrent with a partial loss of SFP water inventory. These analyses indicated that sufficient time is l

available to restore a makeup water source to the SFP prior to any uncovery of spent fuel.

Therefore, there are no radioactive releases associated with this postulated event.

5.4 Decommissioning Events The Trojan Decommissioning Plan has further analyzed a number of potential events which could be postulated to occur during decommissioning activities and result in the release of radioactive materials. The decommissioning activities evaluated included events with the potential for liquid and/or airborne radioactive releases.

During decommissioning activities, contaminated liquids will primarily be generated inside buildings. If there is leakage of these contaminated liquids, the liquid would flow to the floor ,

and equipment drain system, and would be disposed of through the normal plant discharge  !

system, which is a monitored release pathway. Engineering and/or administrative controls will be established to ensure the quantity of radioactive liquids stored within plant buildings do not exceed the capacity of the available liquid waste processing equipment.

- Administrative controls contain restrictions on the amounts of radioactive material that may be stored in temporary tanks (tanks used for temporary storage ofcontaminated liquids located 6

DSAR Section 6.2," FUEL HANDLING ACCIDENT" 1 26 Revision 4

ENY1RONMENTAL REPORTSUPPLEMENT- POST OPERA TING LICENSE STAGE n ex+erior to buildings). These restrictions ensure that potential liquid releases from such G temporary tanks are within the limits of 10 CFR 20, Appendix B, at the nearest potable water and surface water supply in unrestricted areas. Storage ofliquid wastes during decommissioning ,

activities will be subject to these same restrictions, or alternatively, the wastes will be stored such that releases would be contained i'y appropriate engineered features such as dikes, dams, and '

overflows routed to plant drains.

The potential consequences of such events are less than the calculated doses at the exclusion area boundary from an airborne release of radioactive material.

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The events that could involve airborne releases were grouped into one of four categories:

1. Decommission activity events, including decontamination, dismantlement, and materials handling events.

2. Loss of support system events, including loss of offsite power, cooling water, and 1 compressed air. -

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3. Fires and explosions. '

4. External events (earthquake, external flooding, tornadoes and extreme winds, volcanic j 4

activity, lightning, and toxic chemical events).

The potential consequences of such events at the exclusion area boundary are less than the EPA PAGs and less than the preventive PAGs established by the Food and Drug Administration for low impact protective actions (0.5 rem TEDE, bone marrow CDE, or other organ CDE, and 1.5 O

rem thyroid CDE).

Offsite radiological events related to decommissioning activities are. limited to those associated with the shipment of radioactive materials. Radioactive shipments will be made in accordance with the applicable regulatory requirements. The radioactive waste management program and the Nuclear Quality Assurance Program ensure compliance with these requirements.

Compliance with these requirements ensures that both the probability and the consequences of an offsite event do not significantly affect the public health and safety.

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ENVIRONMENTAL REPORTSUPPLEMENT. POST OPERA TING LICENSE STA GE 6 Environmental Monitoring Activities 6.1. Final Radiation Survey and Release Criteria

} Final Survey Plan i

After completion of decommissioning a,ctivities, PGE will conduct a final radiation survey of the Trojan site to verify that surface contamination levels, concentrations ofradioactive materials in  !

the soil and water, and direct radiation levels have been reduced to levels that will allow release i p of the site for unrestricted access.

l Radiation monitoring instruments used during the conduct of the final radiation survey will be selected as appropriate for the physical and environmental conditions and the type ofradiation being measured. The radiation surveys will be performed by properly trained individuals using calibrated survey instruments. The survey instrumentation will be controlled by specific procedures that define accuracy requirements, and calibration techniques.

Applicable portions of the Trojan Nuclear Quality Assurance Program, described in topical report PGE-8010, " Portland General Electric (PGE) Nuclear Quality Assurance Program," will

be implemented during the conduct of the final survey plan and periodic audits will be performed in accordance with the Nuclear Quality Assurance Program to verify survey activities comply with established procedures an'd applicable aspects of the Nuclear Quality Assurance l Program.

! Final Relemme Criteria

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The final release criteria is contained in PGE-1078, " Trojan Nuclear Plant License Termination l

Plan," which is a supplement to the DSAR. The Trojan Nuclear Plant License Termination Plan l

is required by 10 CFR 50.82 to demonstrate that the Trojan facility and site nill meet the l radiological criteria for license termination. The Plan describes the scope and methodology of l the final survey process, quality assurance measures, access control procedures, and how l i

' implementation of the Plan will demonstrate that the plant and site meet the 10 CFR 20.1402 l criteria for unrestricted release of the site. l DOcurnentation -

i PGE will prepare a final survey report. This report will provide a complete record of the l

radiological status of the site and comparison to the established guidelines for termination of the i

license. The report will also contain sufficient information to enable an independent re-creation and evaluation of the survey and the results derived from the survey. PGE will submit the final j report to the NRC.

! After it is determined that the site meets the release criteria for unrestricted use by the

. performance of the final status survey, the report on the final survey results will be submitted to

! the NRC.

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ENY1RONMENTAL REPORTSUPPLEMENT. POST OPERA TING LICENSE STAGE l

,. 6.2 EnvironmentalRadiologicalSurveillanceProgram b' The Technical Specifications, contained in the facility's license, require that PGE monitor the environment in the vicinity of the site to detect the presence of radioactive materials.7 The results of the surveillance program are compiled on an annual basis and submitted to the NRC.

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The environmental radiological surveillance program includes the monitoring, sampling, analysis, and reporting of radiation and radionuclides in the environment in accordance with the methodology and parameters in the ODCM.

There is no indication that the operation of Trojan has had a radiological impact on the environs around the site.

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.. i IN NMM REPORTSUPPLEMENT-POSTOPERATINGIJCENSESTAGE O. -

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ENVIRONMENTAL REPORTSUPPLEMENT- POST OPERA TING LICENSE STAGE 7 Environmental Approvals 7d FederalRequirements 10 CFR 50.82, " Application for termination oflicense", is the principal federal regulation governing decommissioning ofpower reactors. The regulation requires that utilities apply for termination of their operating license within two years following the permanent end of reactor operations. The rule also requires that utilities submit a proposed decommissioning plan along l with the application for termination oflicense. The Trojan facility formally ceased operation on ,

January 27,1993. PGE submitted an application for termination of the 10 CFR Part 50 license I and a proposed decommissioning plan to the NRC on or before January 27,1995.

In accordance with 10 CFR 50.82, the proposed decommissioning plan contains:

1. A description of the chosen decommissioning alternative and a description of the l activities involved.

2. . A description of controls and limits on procedures and equipment to protect occupational and public health and safety.

3. A description of the planned final radiation survey.

4. An updated cost estimate arid comparison with the present funds set aside for decommissioning, and the plan for assuring the availability of adequate funds for completion ofdecommissioning.

5. A description of the technical specifications, quality assurance provisions and physical security plan provisions in place during decommissioning.

NRC regulations

• define " decommissioning" as those activities "...to remove (the reactor) safely l from service and reduce residual radioactivity to a level that permits release of the property for unrestricted use and termination oflicense." Under this definition, decommissioning does not include the removal or disposal of nonradioactive structures beyond that necessary to allow unrestricted access to the site. Therefore, such activities are beyond the scope of this supplement to the Trojan environmental report.

10 CFR 51.53, " Supplement to environmental report," requires that a uti!ity applying for j authorization to decommission a nuclear power reactor submit a supplement to the environmental l report to address the post operating license stage of the facility. This report should reflect any l

new information or significant environmental change associated with the proposed decommissioning activities. This report is intended to satisfy this requirement.

l- A new rule covering explicit radiological criteria for decommissioning remains under development by the NRC at this time. The NRC published a proposed rule for comment in

! August 1994? Pending publication of a final rule, the existing guidance documents along with l l available draft criteria have been used in development of the proposed site release criteria for the Trojan decommissioning plan.

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10 CFR 50.2, " Definitions" 59 FR 43200, " Radiological Criteria for Decommissioning", August 22,1994 31 Revision 4

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ENVIRONMENTAL REPORTSUPPLEMENT- POST OPERA TING LICENSE STAGE Radioactive waste treatment systems will process liquid waste by holdup, filtration, evaporation, and demineralization. Discharges will be treated and sampled to insure that they are within the limits established in the Commission's regulations,10 CFR Part 20 and the provisions of the facility license.

10 CFR 71, "Fackaging and Transportation of Radioactive Materials", contains regulations governing the packaging ofradioactive materials for shipment from the Trojan site.

7.2 State andLocalRequirements The State of Oregon regulations applicable to the decommissioning ofnuclear installations are contained in Oregon Administrative Rules (OAR) 345, Division 26.

OAR 345-26-320 and OAR 345-26-330 require Oregon Department of Energy review and approval of an Environmental and Effluent Monitoring Program, and a Radiological Environmental and Effluent Monitoring Program, respectively. These regulations also govern changes to those programs.

OAR 345-26-370 provides standards for Energy Facilities Siting Council approval of the proposed decommissioning plan. The Council will review the proposed decommissioning plan to verify that the proposed activities will not adversely affect the health and safety of the public or the environment. The Council will ensure that the plan contains criteria for the free release of materials and the area, and, after decommissioning, the exposure rate at one meter from all surfaces in the facility buildings and outdoor areas shall be 5 R/hr or less above the background.

(q/ OAR 345-26-370 requires that the Decommissioning Plan contain the following:

1. The plan must contain provisions that require removal from the site of all radioactive waste on a schedule acceptable to the Council. Spent nuclear fuel and other radioactive materials that must be disposed ofin a Federally approved facility may be stored on the site until such a Federally approved facility will take the fuel and these radioactive materials.

2. The plan must contain an acceptable program for monitoring and controlling effluents to ensure compliance with applicable state and federal limits. This program may be incorporated by reference, ifit has previously been approved by the Council.

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3. The plan must contain a program for radiological monitoring to ensure the environment is not being adversely affected. This program may be incorporated by reference, it has previously been approved by the Council.

4. The plan must contain provisions for removal or control of hazardous waste that are consistent with applicable Federal and State regulations.

5. An analysis'of decommissioning alternatives shall be provided with the plan, satisfactory to the Council. This analysis will describe the bases for the decommissioning alternative selected, and shall include a comparison of SAFESTOR and DECON. The analysis must demonstrate that impacts to public health and safety for the option chosen are bounded by the alternatives analyzed above. The analysis must 32 Revision 4

ENVIRONMENTAL REPORTSUPPLEMENT. POST OPERA TING LICENSE demonstrate that the alternative chosen protects the environment and the health and safety of the public consistent with State and Federal statutes, rules, and regulations.

OAR 345-26-370 also contains requirements for revision of the Decommissioning Plan.

In November 1994, the Energy Facilities Siting Council approved the removal of the steam generators and pressurizer prior to approval of the decommissioning plan. Regulations governing their removal are contained in OAR 345-26-370(9).

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