ML20205A180
| ML20205A180 | |
| Person / Time | |
|---|---|
| Site: | Three Mile Island  |
| Issue date: | 10/03/1979 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| References | |
| NUREG-0591, NUREG-0591-R01, NUREG-591, NUREG-591-R1, NUDOCS 8504250448 | |
| Download: ML20205A180 (29) | |
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USE OF EPICOR-II AT THREE MILE ISLAND, UNIT 2 l
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PREPARED BY OFFICE OF NUCLEAR REACTOR REGULATION
- U. S. NUCLEAR REGULATORY COMMISSION OCTOBER 3, 1979 4
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. ENVIRONMENTAL ASSESSMENT: USE OF EPICOR-II AT THREE MILE ISLAND I _n 35 OI ki" lb..a c i s f.s =l .2+._J.:=[X=T.[.
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Thed p rdpose d fa ctionmi s=to iiis e 0a ny stem ;z E P I CORLI I ,~ *fo rstb e Zcl ea ndp MMM9 of radioactive contaminated waste water whicn has accumulated in the Unit 2 auxiliary building tanks because of the March 28, 1979 accident at Three Mile Island (TMI). The proposed action is limited to cleanup and storage of such waste and includes the impact of temporary storage, packaging, handling, transportation, and burial of the solid waste generated from the cleanup operation using EPICOR-II.
- This action does not include the disposal of tn3 decontaminated waste.
As indicated in Section 2.0 below, the disposal of this water will be
. covered in a separate assessment. . In addition,- treatment and disposition of water in the reactor containment building will also~be~ covered in a -
separate assessment.
This assessment is an evaluation of the effect that the proposed action will have on the public health and safety, and on the environment including
. a consideration of occupational exposures and the risk of accidental releases, and a discussion of alternatives to the EPICOR-II system.
2.0 Introduction r
As a result of the March 28, 1979 accident at the TMI Unit 2 facility, a significant amount of radioactive contaminated water has been generated
.and collected in Unit 2 auxiliary builaing tanks. This waste water was produced primarily from the following four sources: (1) an inventory of waste water existed in Unit 2 auxiliary building tanks prior to the accident (approximately 130,000 gallons, some of which has been used as makeup (makeup is water which is normally added to the reactor coolant system for the purpose of controlling reactor coolant inventory) water to the Unit 2 reactor); (2) during the early phases of the accident, contaminated water from the reactor containment builcing sump was trans- '
ported to the auxiliary,. building and collected in various tanks; (3) letdown (letdown is water which'is normally removed from the reactor coolant system for the purpose of controlling reactor coolant inventory and l chemical and radioactivity content; it is depressurized and cooled prior to reaching the auxiliary building tanks) from the reactor coolant system has
, resulted in a net increase to the inventory; and (4) normal leakage from e
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system components in the auxiliary building has been a small but continuous source of waste water to the inventory which currently exists in all of the auxiliary building tanks (approximately 280,000 gallons). The level of contamination of the water in these tanks ranges from less than 0.1 to 35 uCi/mi of Cs-137. Because of the relatively short half-life of I-131 (8.1
. aays) compared to that of Cs-137 (30 years), Cs-137 has become the cominant isotopic contributor. The quantities and activity levels of the current
, inventories in the auxiliary building tanks are discussed in Section 3.3.3.
Following the March 28 accident, Metropolitan Ecison Company (the licensee) initiated the design and construcftion of assyst m, the design basis of which was to decontaminate water with an activi ty level up to 100 uC1/mi of I-131 and Cs-137, the principal radionuclides present in the waste water for radiological dose considerations. As indicated in Table 2, the activity level of I-131 and Cs-137 in the water to be treated in EPICOR-II is less than 40 uCi/ml. The design and construction of a new processing system was necessary for the following reasons. The existing liquid waste processing systems for Units 1 and 2 were designed for processing water with significantly lower levels of activity than currently exist in the Unit 2 auxiliary building tanks. For example, the expected reactor coolant concentration of Cs-137 during normal operation of the plant is 0.018 uCi/ml or a factor of approximately .
2,000 times lower than the highest Cs-137 concentration presently in '
tne auxiliary building tanks. 'In addition, the contaminated conoition of the Unit 2 auxiliary building after the accident rendered the building unusable for the purpose of continuous, planned processing of the inven-tory of waste water from the building radwaste control panel. The .
recognized need for a new processing system resulted in the development of the system which is now known as EPICOR-II.*
~ .In response to a_ complaint for injunctive relief filed by the City of ,
Lancaster, PerinsyNania,' in the United States District Court for the' District-of Columbia, the United States Nuclear Regulatory Commission directed its staff to prepare an environmental assessment regarding proposals to decontaminate and dispose of radioactively contaminated waste water from the TMI 2 Unit 2 facility. The assessment is to be
- divided into several portions of which this is the first. This portion oeals with the proposed decontamination of the intermediate-level **
!Epicor,Inc.,_ Linden,_N.J..
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- Intermediate-level waste is ' defined as waste having 1-131 and Cs-137'-
, concentrations greater than 1 uCi/mi but less than 100 uCi/ml.
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. i waste' water in the Unit 2 auxiliary building tanks using the EPICOR-II system. This assessment includes discussion of potential risk of planned
. (gaseous) and accidental (gaseous ano liquia) releases, and a discussion of alternatives to the EPICOR-II system. It does not consider the dis-position of the decontaminated water following use of EPICOR-II since
. this is precluded pending an evaluation of the various disposal alter-natives. Use of EPIC 0R-II does not preclude implementation of the f
. various disposal alternatives.
This assessment is the formalization of the evaluations and regulatory guicance that have been provided at TMI from March 28 to the present.
During that period, and on a continuing basis, Lne NRC on-site support staff has been engaged in design a'nd safety ev:iuaticn of the licensee's proposed means for processing intermeciate-level waste water, including an evaluation of the need for EPICOR-II (see Section 2.1). The NRC staff concurred with the licensee that design, construction, and '
operation of EPICOR-II should proceed on a high priority basis. The NRC staff has provided design guidance and criteria for the EPICOR-II processing system, the building housing the system, the building exhaust filtration system and the process vessel vent fil.tration system. The
. NRC staff has monitored and inspected the design, construction, and preoperational testing of EPICOR-II since its inception. The EPICOR-II system which has evolved from this regulatory effort has been designed for remote receipt, handling, and processing of con- ?
taminated water from the TMI Unit 2 auxiliary building with minimal occupational exposure and no adverse impact on the health and safety of the public.
~
2.1 Need for Decontamination The March 28 accident at TMI Unit 2 and subsequent recovery operations have generatec a substantial amount of contaminated water which is
_ contaitied in the reactor-building-and in-tanks :in 'the au8iliare bdi1~ ding (see' Section 3.3.3) . Although these buildings are of high integrity such that_the contaminated water can be positively controlled for an indefinite period, there are several reasons why decontamination of the water would be beneficial. Available capacity of the tanks in the auxiliary building is needed in the event that pumping of water from the reactor building is necessary to protect the operability of reactor building com-ponents~ and systems which maintain continued safe shutdown of the facility.
Ine waste water in the auxiliary building continues to be a source of exposure to personnel needing entry into the auxiliary building. The con-7 3._ _tinued..safeu shutdown .of_ T11I. Uni t .Z_ depends..upon_thejoperabi14tynof--ogginal m ---
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plant equipment located in the auxiliary builaing and the use of adoitional equipment oeing installed in the course of completing modifications in progress. The surveillance and maintenance of this equipment and personnel exposures associated with these actions, which are necessary to assure maximum reliability, are adversely affected oy radiation levels associated with stored liquid. Approximately 50 workers per day are currently providea access to the auxiliary builaing for decontamination, operations and construction purposes.
Although occupational exposure to these workers (approximately 10 mrem / worker /
day; or about 15 man-rem for each month that the situation remains unchanged) is within regulatory limits, any reduction in don resulting from the removal of racioactive water storea in thp, auxiliary bur. ding tanks is considered a positive action. The total exposure from this ccurce is primarily a function.
of the elapsed time to ceciding to remove and ,:rocess the water.
The removal of stored contaminated water will have the additional benefit of permitting decontamination - now precluded by high radiation levels -
of some areas of the auxiliary building, including rooms housing reactor coolant bleed tanks, neutralizer tanks, and the miscellaneous waste holdup tank. Therefore, it is important to process the inventory of
- water in 'the Unit 2 auxiliary building tanks in order to innobilize the entrained activity and thereby reduce potential souces of environmental and occupational exposure and provide surge capacity for water transferred from the reactor Du11 ding. The EPICOR-II processing system has been > ,
specifically designed and constructed for the purpose of processing TMI 2 intermediate-level waste water and represents the best alternative for cesired decontamination of that waste (see Section 5.0, Alternatives to the Use of EPICOR-II).
3.0 EPICOR-II System 3.1 Housing of EPICOR-II in the Chemical Cleaning Building
~
'Th'e EPICdR'-If sys~ tem ihous~ed'in an'eiistiing on-site'sitructurekalied the chemical cleaning building. This building was originally intended to be usea in the chemical cleaning of the steam generators for TMI Units 1 and 2. It is a rectangular shaped building with dimensions of 48 feet wide by 60 feet long by 52 feet high. The foundation of ,
the building and the walls up to a height of 13.5 feet above the basement floor are concrete ano the upper walls and roof are of
. structural steel. 4 i
~. _ _. ..The .founcation .of _the_. buil.di ng i.s.,cesigned to_ sei smic_Cate_ gory _I .
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A floor ' drain system is included in the design of the Chemical Cleaning Building. The drain system routes leakage from pumps, and other components,
. possible overflows from tanks, demineralizers, and the demineralizer/ filter to a lined stainless steel sump. The floor of the Chemical Cleaning Building and up to a height of three feet on the walls is covered with a strippable
._ coating. In the event of a spill, decontamination of the floor can be accomplished by flushing with clean water or a decontamination solution.
. The.. containments and decontamination solution are then routed to the sump
. -for processing.
3.2 Modifications for EPICOR-II 4
In . order to convert the chemical cleaning buikdir.; fcr use in decon-
, taminating intermediate-level waste, several modifications were made to the building. These included the following: ,
- 1. The installation of the EPICOR-II system (vendor supplied equipment) in the building. Specifically, a prefilter/demineralizer, a cation bed demineralizer, a mixed bed cemineralizer, precoat and chemical addition tanks and associated pumps, pipes, valves, and
. instrumentation for the EPICOR-II system;
- 2. . The addition of shield walls around EPICOR-I'I equipment. The shield walls,were added for the prot?ction of ' personnel involved in the operation of this system (a description of the shielding is con-
., tained in Section 4.0);
. 3. The addit. ion of an overhead monorail hoist system. The hoist system was provided for removal and replacement of the demineralizers and prefilter/demineralizer. The monorail system extends from the north side of the building above the prefilter/demineralizer through
, the south end of the building extending 18 feet outside the building over, a cask loading area at which point the shielded prefilter/
~- , Temineralizbr- and deinineralizer casks can be loaded-onto a truck; . '
- 4. The chemical cleaning building was made into a low leakage confine-ment building by spraying the interior of the structural steel portion of the building with an epoxy sealant. The sealant was added to prevent air and radioactive material outleakage from the building; ,
- 5. The addition of an exhaust ventilation filtration system to maintain the chemical cleaning building at a negative pressure. This also E3 ~
. minimizes air.outleakage and-directs air flow through the filtration usys&g:a.s This. system includes filtrationsof the air through Ta1_
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prefilter, a high efficiency particulate air (HEPA) filter, a charcoal adsorber and a final HEPA filter. The purpose of this filtration
. system is to remove racioiocine and radioactive materials in particulate form present in the air before it is released to the environment. A new builoing was constructed, directly adjacent-to the east side of the existing chemical cleaning building, to house the air filtration equipment; 6.' The addition of a TV monitor control building directly adjacent to the
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northwest section of the chemical cleaning builoing. Since operation of the EPICOR-II system is by remote means, tr .'s building is pro-video for remote system operations where the ' PICOR-II system can be controlled. In adoition, there are fix Ti monitors located at different points in the chemical cleaning building to provide for remote viewing of the system during normal operation. ,
3.3 Design of the EPICOR-II System The EPICOR-II system is a liquid radwaste processing system supplied by EPICOR,,Inc. The system is designed to decontaminate by filtration and ion exchange radioactive contaminated water contained in the auxiliary building tanks of TMI Unit 2 and to transfer this decontaminated water to Unit 1 or other tanks for storage. Plans are currently being formulated to allow for the disposition of the decontaminated water from Unit 2. .
Ion exchange is the process by wnich radioactive ions are removed from
- solution in the contaminated water by resins in the ion exchanger. The use of filtration and ion exchange in the treatment of racioactive waste l water is standard practice in nuclear power plants and the principles upon which they a're based are described in NUREG/CR-01411 and NUREG/CR-01432, respectively.
The EPICOR-II system is designed to function in such a manner as to limit gaseous releases. of radioactive material..to the. environment to levels .which -
are as low as is reasonably achievable'," in accordance With 10 CFR Part 50.34a4 and 10 CFR Part 205 . In addition, it is designed to be operated and maintained in such a manner as to maintain exposures to plant personnel to levels which are "as low as is reasonably achievable," in accordance
. with the guidance given in Regulatory Guide 8.86 ,
3.3.1 Description of the EPICOR-II System The EPICORE-II system consists of the following components, all of which
- are_ located.in the. chemical cleaning building except as noted. A functional.
d description of these components [is given51n the oiscussion below:: -
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- 1. < Processing pumps (5)
- 2. Transfer pump
- 3. Prefilter/demineralizer - containing precoat material and cation bed resin
- 4. Demineralizers (2) - one cation bed followed by a mixed bed
- 5. Miscellaneous waste holdup tank - located in the TMI Unit 2 auxiliary building.
- 6. Clean wastes receiver tank (formerly the rins>. nolo tank)
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- 7. Off-spec water receiving / batch fank (forknerly the chemical cleaning solution tank) *
- 8. Chemical cleaning building sump pump
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, 9. . Mono l ail hoist system
- 10. Nentila' tion filtration system
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A simplified flow diagram of the EPICOR-II system is shown in Figure 1.
The EPICOR-II liquia waste processing system operates at essentially atmos-pheric pressure in the following manner. The miscellaneous waste holoup tank .,.
(MWHT) is located in the auxiliary building of Unit 2 and receives water from the specific, auxiliary building and fuel handling builoing tanks *'. Water
, from tanks in the fuel handling building can be routed directly to the EPICOR-II system, however, for operational purposes water. stored in the fuel handling building will be routed through the (MWHT) to EPICOR-II.
Water in the Unit 2 auxiliary building tanks can reach the EPICOR-II system only by being routed to the NWHT. Prior to processing in EPICOR-II, the water is analyzed for radioactivity and chemica1 content to provide estimates
. .of activjtf;buildu;f on.ther.idn exchange resins ~andythe~ nee,d for' req 0 ired 5 chemical addition for system optimization. '
- The first processing pump is used to pump water from the MWHT to the prefilter/demineralizer in the chemical cleaning building through the yard piping. The piping is enclosed in a shielded guard pipe, the open end of which terminates inside the chemical cleaning building. The prefilter/de-
, mineralizer contains a precoat material which enables it to remove particulata radioactive wastes (e.g., activated corrosion products) and other suspended solics. The prefilter also contains cation bed resin which is highly. .
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- It was realized during the early planning stages after the accident thitt additional liquid storage capacity would be required. Space was available in the Unit 2 fuel pool to locate six storage tanks with 'a cocained volume of 110,000 gallons.
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4 f through the prefilter/demineralizer, the water is circulated by the proces-sing pumps through the two demineralizers arranged in series. The first demineralizer also contains cation resins which also makes it highly afficient for removal of cesium and other cationic radionuclides from the waste stream (removal efficiency greater than 90%). The second de-
. mineralizer contains mixed resins (cation and anion) which are efficient for removal of both cationic and anionic radionuclides, including cesium and iodine (removal efficiency greater than 90%). After processing, the water
. is collected in the clean water receiving tank (CWRT) which has a capacity of 133,000 gallons. In the CWRT the water will be samplea and analyzed for nuclide identification. If the analysis show that the processea waste contains concentration of r#dioactiv.isty be'.aw predetermined limits, the water will then be transferred to the TMI Ur.it 1 or 2 liquid waste management system to be held for ultimate disposition. These predetermined limits will be specified in the system operating procedures and in the ,
plant radiological effluent technical specifications. Processed waste which is not suitable for transfer to TMI Unit 1 or 2 liquid waste management system will be pumped to the off-spec water receiving / batch tank (0WRT) which has a capacity of 95,000 gallons. Water in this tank will be recycleo through the EPIC 0R-Il system for additional processing.
The monorail hoist system consists of a 20-ton hoist mounted on a monorail which extends from above the prefilter/demineralizer, across the top of the demineralizers and to approximately 18 feet outside of the chemical cleaning building' over the cask loading area. The purpose of the hoist system is to provice for removal and replacement of the demineralizers and prefilter/
demineralizers when they have reached the maximum radioactivity loading per-mitted by the operating precedures or become chemically depleted. The radioactivity loading is limited by contact radiation dose rate readings on the vessel to meet personnel handling requirements as discussed in Section 4.0. The operation of the monorail hoist system is done remotely by use of a closed circuit TV system located in the control building adjacent
. to the. chemical c3eaning building. .
The chemical cleaning building ventilation system maintains a negative pressure in the building. The exhaust ventilation system consists of a j heating unit, moisture separator, a filtration unit, a fan assembly, a i
radiation monitor, and a weatherproof enclosure. Building exhaust air is passed through a moisture separator and an 80 KW heater to remove moisture from the air and lower its relative humidity to improve the iodine removal capabilities. The air is then passed through the filtration unit which consists of a prefilter, a high efficiency ~
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l radiciodine that may be present in the offgas. Tiie fan assembly draws l air from the building and exhausts it through ducting to a local stack at the roof line of the chemical cleaning building. The radiation )
monitor installed in the discharge duct from the fan samples the. air i in the fan discharge' line. Measurement of the ventilation system exhaust racioactivity is providea both locally and remotely in the control building in the event that radiation levels in the effluent stream
, exceed a predetermined level. These predetermined levels will be spect-fied in the system operating procedures and in the plant radiological effluent technical specifications.
The chemical cleaning building sump is a stainle.s steel lined pit located in the northwest corner of the building. Any w: er from process vessel
, overflow or from other equipment leakage is collected in the sump. A sump pump transfers water from the sump to the 0WRT. The sump pump
- starts automatically on a high level indication in the sump.
3.3.2 Sources of Radioactive Water
~
The EPICOR-II system will process the approximately 400,000 gallons
. of intermediate level waste water currently contained in TMI Unit 2 auxiliary building tanks. Waste water that is acceptable for processing in the EPICOR-II system is that which has Iocine-131 and Cesium-137 concentrations of lets than 100 uCi/ml (intermediate level waste). Water that has' higher radioactivity than intermediate level waste will be the subject of a separate environmental assessment. The tanks in THI Unit 2 auxiliary building which are to be processed using the EPICOR-Il system
, are the foll.owing:
- 1. Reactor coolant bleed tanks (3);
-- 2. Miscellaneous waste holdup. tank; l
3~ ' Auxiliary building sump;
- 4. Auxiliary building sump tank;
- 5. Neutralizer,tankN(2); -
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- 6. Waste evaporator condensate tanks (2); -
- 7. Cnntaminated drain tanks; .
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- 9. Fueliancling-Builcing tanks; (tank-farm). .
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3.3.3 Volume 'and Activity of the Water to be Processed by the EPICOR-II System Table 1 contains a listing of waste water inventories stored in TMI Unit 2 auxiliary building tanks which are intended to be processed by the EPICOR-II system. Table 2 contains a listing of principal radionuclide concentrations present in the waste water for radiological dose considerations for each.of the sources in Table 1. Table 3 lists the half-lives of the principal radio-
, nuclides listed in Table 2.
~
The liquid volumes are established from tank level measurements taken by plant personnel. Activity levels are established from liquid samples analyzed by in-plant staff, as wellfas by Babcock & Wilcox. All liquids processed through the EPICOR-II system will tave activity levels of less than 100 uCi/ml.of Cs-137. Cs-137 will be the predominant and controlling isotope at the time these liquids are processed. ,
~
3.4 Design Features for Spill Prevention There are a number of design features built into the EPICOR-II system to prevent spills of radioactive water. The following is a listing of these features and a discussion of each:
- 1. The piping carrying radioactive contaminated water from the miscel s
. laneous waste holdup tank in the auxiliary building through the yari1 to the EPICOR-II system in the chemical cleaning building is enclosed 4
within a four-inch diameter guard pipe. Radiation shielding has been
- provided'around the guard pipe to minimize personnel exposure (see Section 4.0 for a discussion of radiation shielding ano personnel .
exposure);
- 2. All system overflow lines run to the chemical cleaning building sump. The sump pump routes all collected leakage to the off-spec water receiving / batch tank. The' sump pump is started ,either .-
~ manually from the~ control panel or automatically. If pump start
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is automatic, it occurs when the sump level reaches a preset height. A high sump-level alarm is also provided on the control panel in the control building;
- 3. Water level in the prefilter/demineralizer is maintained by a level probe and a solenoid valve. On high level, an alarm will sound at the
.. pump control panel in the control building;
_ _ _ , _ _ 4. Levell_instrumentationJ n_the..demineralizers .is.similar_to that for . . -
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- 5. For the clean water receiving tank and the off-spec water receiving /
batch tank, an overflow line with a loop seal is provided near the top of the tank. The overflow line routes any tank overflow to tne chemical cleaning butiding sump. Tank level indication is providea on the control panel in the control building;
- 6. All system components which have flexible hose connections are
, provided with drip trays to collect leakage. Tubing from these drip' trays is routed to the nearest floor or equipment drain;
- 7. All system liquid piping is welded stainless steel to prevent system leakage. All installed fittings and hoges h. We pressure ratings that exceed the maximum discharge pressure df the pumps used. All oischarge
, hoses have a pressure rating of 600 psig or greater. Ali hoses and fittings will be hydrostatically tested prior to use. Pump diaphragms are designed to rupture at pressure greater than 125 psig. The '
maximum available air pressure to drive the pumps is 100 psig (thus protecting diaphragm integrity). All hose connections are taped and .
wrapped with plastic to contain drips from fittings.
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, All auxiliary building tanks are vented and operate at atmospheric pressure.
There are also design features to prevent spills of radioactive contam -
nated water from the tanks in the auxiliary building which are to be
, processed in EPICOR-II. These features have been previously evaluated and found acceptable in the Safety Evaluation Report relatep to the
, operation of, the Three Mile Island Nuclear Station, Unit 2. As indi- .
cated in that document, these cesign features will include level instru-mentation which will alarm in the control room, and curbs and drains which will collect liquid spillage and retain it for processing. Also, the release.of.All proc l_1. qui'ds fr;om -
or 2_di~scharge, line,es_ s. 'P sed.iping ' are systems ,TMIso designed . Unit;2'is through that' transfers of the, TMI' U processed water can be made between the EPICOR-II system, Unit 1, and Unit
- 2. In addition the capability also exist for transferring water to on site tanks outside the plant and not interfaced with discharge pathways.
Water transferred to Unit 1 or back to Unit 2 will be placed in tanks
, . and isolated from all other plant liquid systems. However, it is possible
! for valv.es to leak and for operators to make errors in valve line-up and
! recontaminate the processed water. To prevent the unauthorized release l .
of liquias from the site, existing radiation monitors in the discharge i
if nes from Units l and 2 which alarm and automatically initiate closure h
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We have also evaluated the potential consequences of a pipe break in the EPICOR-II system inside the chemical cleaning building. From a radiological standpoint, the worst case pipe creak is a break in the I
liquid waste inlet pipe to the EPICOR-II prefilter/cemineralizer. We conservatively assumed that during the accident, the EPICOR-II system
- operator would not monitor the system parameters for loss of liquid flow or processing pump shutoff from each of the three process vessels, or notice any abnormalities on the remote TV viewing system. Further, we assumed that
' the entire contents of approximately 20,000 gallons from the miscellaneous waste holdup tank would spill on the floor and par.tition iodine with a factor of 0.0075. The partition factor (the rati'> of the quantity of a nuclide in the gas phase to the total quant.ty in both the liquid and gas phases when the liglid and g'as are at equilibrium) value
, of 0.0075 is based on data presented in NUREG 0017.3 We assumed that the water is from the "C" reactor coolant bleed tank and that the iodine concentration in the spilled water is 3 uCi/cc (the highest concentration as of June 15,1979). The building air is venti-lated through the chemical cleaning building air filtration system con-sisting of HEPA filters and charcoal adsorbers and the iodine is subjected
- to an assumed decontamination factor (DF) of 20. Assuming a conservative meteorological dispersion factor (derived from R. G. 1.4)5 ThL calculated inhalation thyroio dose to an individual at the site bounaary is less t' nan 0.001 of the 10 CFR Part 20 limit.
We have also considered the potential consequences of a failure of the monorail system resulting in the dropping of a liner of demineralizer media during liner transfer operations. We conservatively assumed that, even though the finer is a carbon steel vessel, it ruptures when dropped re-leasing its contents to the truck loading pad. Since the demineralizer media will be dewatered prior to removal, the contents will be a relatively dry material which will remain on the loading pad.
~
~
l In addition,.we conservati'vely1 assumed that, even though there is no driving force for the radioactivity to' be removed from the resins, the iodine partitions from the resin beads in a manner similar to that discussed above for water partitioniTig and becomes airborne. Based upon the specific j . activity of iodine on the resin corresponding to the iodine inlet concentrations of 3 uCi/ml (the highest concentration as of June 15, 1979) and the meteorology discussed above, the calculated inhalation l
thyroid ~ dose to an individual at the site bouncary is less than 0.01 of l the 10 CFR Part 20 limit. -
i
^* 2 n --
t e L. -. _ --
e 3.5 Desigri Features to Minimize Gaseous Releases
~
There are a number of design features built into the EPICOR-II system ,
to minimize gaseous releases to the environment. The following is a l a listing of these features and a discussion of each: l
- 1. The chemical cleaning building has been sealed with an epoxy sealant to minimize both inleakage and outleakage of air;
- 2. An exhaust ventilation system has oeen acded to the building to main-tain the building at a negative pressure. Ttis prevents outleakage of air from the builaing ano also routes an; airborne radioactivity
, in the building to the exhausgventilajion -iltration system;
- 3. The filtration system, consisting of HEPA filters and a charcoal ,
adsorber provides removal of radioactive particulates and radio-iodine, respectively, from the building air before it is released to the environment;
- 4. A radiation monitor in the ventilation system ductwork provides an indication of radiation levels both locally and in the control building. In addition, the radiation monitor will provide an alarm if the radioactivity in the release exceeds a precetermined level (this predetermined level will be specified in the system operating procedures and in the plant radiological effluent technical <
specifications). In this manner, releases of radioactivity will be carefully controlled within the predetermined limits set forth in the sys. tem operating procedures and the plant radiological effluent technical specifications;
- 5. Within the plant, the system tank vents are provided with in-line heaters, moisture separators, HEPA filters, charcoal adsorbers, and HEPA filters to adsorb evolved iodine and remove particulates. The
--x-vents from the prefilter/demineralizer and demineralizers are vented to the off-sp'ec-water receiving / batch; tank;. __
- ;" . _. M
We have calculated gaseous releases as a result of operation of the EPICOR-II system based on the design capabilities of the system and the contami-nants in the waste water. Based on these calculations, we estimate the release of Xe-133 will be less than 1 Ci and the release of I-131 will oe less than 1 x 10 -4 Ci as a result of processing all of the auxiliary '
buildi ng . water. The_off-site. dose,_as_a result of such releases, would De Q
~ - - -
insignificant (i .e., a total-cody cost ef less than.0.0001. mremiana a5 cth.yroid dose of less than 0.D1 mrem;%e cases are less tha'n 0.01%
.m
~ ,. and D.l*., and thyroid dose . design -
oojectives respectively, of 10 CFR Partof50,
- the total'.bgI ).
Apendix
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- 14 _
3 At the time of the initial writing of this environmental impact assessment iodine-131 and Cs-137 were the principal radionuclides considered for radiological dose considerations. As of September 28, 1979 approximately ten half-lifes for iodine 131 have passed, thus removing iodine-131 from the waste. The dissolved noble gases of xenon have likewise decreased to
.- insignificant levels due to radioactive decay. Since the only release pathway considered in this assessment are gasvus releases, the removal by radioactive decay of iodine-131 and short half life noble gases have further reduced the risks of possible releases via the gaseous pathway.- The calculated gaseous releases provided above establishes bounding values for estimating the maximum impact of I-131 and Xe-133 releases. Due to radioactive decay the impact of of,f-site doses .ill be significantly less 4
than the calculated values above. The basis und for estimating bounding
., values follows: .
- 1. Data obtained on nuclide activity levels in the reactor coolant and the reactor coolant bleed tanks as of June 15, 1979;
- 2. Data on EPICOR-II system flow rate and chemical cleaning building ventilation rate;
- 3. Design of charcoal adsorbers on the off-spec receiving tank vent and in the chemical building ventilation exhaust filtration system.
3.6 Conforniance of EPICOR-II System Design with NRC Regulatory Guides
- 1. The EPICOR-II liquid waste processing system and building housing
. the system meet the design criteria of Regulatory Guide 1.143.9
- 2. The building ventilation system for the building housing EPICOR-II is designed in conformance with Regulatory Guide 1.140.10
- f. g
_. .L _ 3.. The-effluent"inonitor -for .the building ventilation Axhaust systemy for EPICOR-II is in conformance with the requirements of h
~
- 4. The radiation protection design of the EPICOR-II system, the chemical cleaning facility, and the spent filter and resin handling systems are consistent with the guidance of Regulatory Guide 8.8, "Information Relevant to Insuring that Occupational Radiation Exposure at Nuclear Power Systems will be as Low as is Reasonably Achievable."
~
[ 4.0 Occupational Exposure ' , ; ',,. 7- -
3 3 _ _
c - - - ,
A' design criterion for the: facility was'that' occupational exposure should-be maintained "as low as is reasonably achievaole." Therefore, the design
.' was made consistent with the guidance of Regulatory Guide 8.8. The sections
'below cascribe the cesign and operational features included to minimize cccupational exposure. The anticipated dose rates and occupational exposures are also cescriDed.
" ~ ~ ' -^ - -~
15 -
i Concrete shield walls,12 inches thick and 13.5 feet high, surround the EPICOR-II processing area. .The prefilter/demineralizer is installed inside a cylindrical concrete cask, 12 inches thick. The cask ic then surrounced by a rectangular lead brick wall, 5 inches thick. The top of ute prefilter/
decineralizer is covered with a portable lead shield. The prefilter/
demineralizer is also covered by a steel lid, 5 inches thick. The lia has
- cutouts for the hose connections. The cation bed demineralizer is installed
. i,nside a cylindrical concrete cask, 12 inches thick. Tne cask is surroundea by a portable lead shield and by a steel lid, 5 inches thick. The lia has i cutouts for hose connections. Shield collars will be installed around the pipes in these cutouts on the prefilter/demineralizer and cation demineralizer.
The uixed bed demineralizer is algo surroupded ;y a rectangular lead brick wall, 3 inches thick. The strainer is shielded'with 6 inches of concrete block. ~
The post-filter is shielded with 3 inches of lead brick. The feed line .
from the TMI Unit 2 auxiliary building is shielded by lead bricks, 4 inches l- thick. Tne shield bell used to transfer the spent prefilter/demineralizer ~
and cation bed demineralizer onto the transport vehicle and cask provides 3-1/2 inches of lead shielding. Concrete walls, 24 inches thick, separate the rooms through which the building is accessed from the room containing the prefilter/demineralizer and demineralizers. A water box window,18 inches thick, is included in this wall to allow direct viewing
~
of the system from a shielded area.
The EPICOR-II facility has radiation monitors mounted inside the lead 4
brick walls around the prefilter/demineralizer and the demineralizers. '
The design criteria call for the prefilter/demineralizer to be changed if the prefilter/demineralizer reaches a dose rate at contact of
, 1000 rem per hour. The cation bed demineralizer, mixed bed demineralizer, .
strainer, and post-filter will be changed when dose rates at contact reach 400, 20, 3, and 3 rem per hour, respectively. We estimate that there
- will be approximately 50 changes of prefilter/demineralizers and demin-
~
eralizers as a result of EPICOR-II processing of:the intermediate level -
'jf -
waste: water'in the-auxiliary -building. ..This estimate' i,s based on~ the 23x
, prefilter capacity and the demineralizer i~on exchange capacity. The total volume of solid radwaste generated is estimated to be approximately
- j. '
2500 cubic feet based on 50 changes of prefilter/demineralizers and demineralizers.
The truck which is used to transfer the spent prefilters/demineralizers and demineralizers to a temporary on-site storage facility has a cylindrical reinforced concrete shell 15 inches thick. The transfer shielo bell holding
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the spent prefilter/demineralizers or cation bed cemineralizer will be placeo insice this concrete shell for adaitional shielaing. The mixec bed demineralizer will be lifted into this shell without a transfer Dell.
After transport from the chemical cleaning building to the temporary on-site storage facility, the spent filters and liners will be transferrea from the tranfer bell to indiviaual shielded cells for temporary storage prior to shipment to a low level waste burial facility. As shipping casks become available, the liners will oe hoisted from the storage cell into the transfer bell, and, thence, to a licensed shipping cask for off-site disposal in an approved facility.
. The control building for EPICOR-Ibis loca$ed omside of the chemical
, cleaning builaing. The operators can control t' e system in the facility from this control building by means of remote cameras, controls and reacouts from.' instrumentation. Using the crane and transfer bell, the spent prefilter/demineralizers and demineralizers can be removed from the facility without entering the EPICOR-II room. Since the hose connections and disconnection of the prefilter/demineral,izer and demineralizer process vessels will require direct hanaling by personnel, quick connect / disconnect hoses and caps will be used. Ladders vill be provideo to facilitate access to the to'ps of the prefilter/demineralizer ano demineralizers to make connections. Features are included to allow flushing of piping and hoses and to allow sampling to be performed from the outsice of the EPICOR-I:I room.
The operators for EPICOR-II will be trained in the operations of the system.
This training will incluae numerous trial operations of the various systems before radioactive water is processed. The EPICOR-II system uses the same type of equipment that the operators are already experiencea in operating. Coverage by health physics personnel will be provided when-ever the EPICOR-II building is accessed.
Sabea.6irthe~c'ontact doss" rate ~11'mitr'on thd piefilter/cemincraliter~and demineralizers, the shielding provided for the process vessels, and the thickness of the lead brick walls, the following is a discussion of estimated radiation dose rates.
The estimated radiation dose rates outside of the lead brick walls sur-rounding the prefilter/demineralizers, cation bed demineralizer and mixed bed demineralizer are 30,1 and 10 millirem per. hour, respectively. The
. estimated dose rate on top of the steel cover plates above the prefilter/
demineralizer and cation oed cemineralizer is 100 ana 40 millirem per hour, ik-9de._2.- .respectively,3i_thiapprox.imate.lygl: fem _per_ hour-aDove theEcutouts due:to_ -- --
IMif6Ud pgis tieami ng .5 Th ee c s.thiateo (do s e (rgte- a bolvg pegxepe c} cemigrggggi=is
is 20 rem per hour. The estimated dose rate at contact with the strainer and post-filter is 3 rem per hour. The estimated maximum dose rate outside ;
the facility is 1 millirem per hour except during prefilter/demineralizer i
- or demineralizer removal by crane. The estimatea dose rate outside of the l the facility is 1 millirem per hour except during prefilter/demineralizer l or cemineralizer removal by crane. The estimated dose rate outside of the transfer bell is 60 millirem per hour with the prefilter/demineralizer in the bell and 25 millirem per hour with the cation bed demineralizer in the bell. The estimated dose rate outside of the shield shell on the truck is 4 millirem per hcur with the prefilter/demineralizer in it, 2 millirem per hour with the cation bed demineralizer.in it, and 700 millirem per hour with the mixed bed demineralizer in it. Th< estimated dose rate at a distance of 50 feet from the truck for each t: pe of vessel is less than .
1^ millirem per hour. For a very short time'auring placement into and' removal 'from the truck or storage cell, the mixed bed demineralizer could have-a maximum dose rate on contact of 20 rem per hour. As discussed in .
Sections 5.2.1 and 5.2.2, the estimated dose rate in both the interim storaga facility and concrete storage facility areas is 5 millirem per hour. To reduce occupational exposures in the interim storage facility and concrete storage facility areas, these areas will be roped off, thus not permi'tting normal personnel access. In this way, there will be very low levels of occupational exposures while the liners are stored onsite.
The estimated maximum dose to an individual at. the site boundary on a continuous basis is less than 1 millirem. This dose includes all of the ~
handling operation and is less than 4% of the 25 millirem annual limit in 40 CFR 190.
Disconnections of hoses and capping of spent prefilters/demineralizers -
and demineralizers will be the highest occupational dose activity associated with EPICOR-II operation. These activities require direct handling by personnel in radiation fields above the prefilter/demineralizer, a cation bed cemineralizer and mixed bed aernineralizer of 100 millirem per y._
~
~ hourc 40 millirem per hour and 20 rem'per hour, respectively. Although
. radiation livels above the' cutouts in the steel plates"above the' prefilter/ ". ~
4 demineralizer and cation bed demineralizer will be higher due to streaming, use of proper tools for disconnections will make exposure to these streaming fields unnecessary. We estimate that a prefilter/demineralizer or demineralizer can be disconnected and capped by a trained operator in an average time of about 30 seconds.
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1 Basea'on the frequency that these activities will De necessary, we estimate that operation of EPICOR-II will cause 1-5 man-rem of occupation cose.
This exposure can be related to an increasd cancer death probability by use of the linear, non-threshhold, dose-rate indepencent, dose-effect relationship. This relationship defines the cies of cancer from radiatign exposure as 10'grobability per year-rem. that Thisan inoividual results in-a probability of 5 x 10-' per year that someone dies of cancer from the
- 5. person-rem occupationel exposure, a number much closer to zero than to one, hence, it is expected that no cancer deaths will result from this exposure.
This estimate includes all activities involved in.the operation of EPICOR-II, the handling and transfer of liners to end from the temporary storage facility, up to the time ghen the gpent prefilter/demineralizer liner and cask or spent demineralizer liner anc cask is loaced on the truck
, for shipment to an approved burial facility. Tnis estimate is a very small percentage (less than 1%) of the total annual occupational dose at a nuclear ,
power plant. .The dose to individuals involved in the operation of EPICOR-II will be within the limits of 10 CFR Part 20 and maintained as low as is reasonably achievable. The dose to individuals will be of similar magnitude to that normally received oy individual workers at a nuclear power plant (i.e.
approximately 700 millirem / year).
5.0 Management of Solid Waste 5.1 Introduction The operation of EPICOR-II will generate approximately 50 liners of dewatered solid waste (prefilter media and ion exchange resia) which will
, require on , site handling, temporary on-site storage, packaging, trans-portation, and ultimate burial in an approved low level waste burial facili ty. The prefilter media and ion exchange resins will be changed well before any resin degradation could occur due to radiation levels.
- The 50 liners will include approximately 32 prefilter/cemineralizer
~. lirie,rs,.8 cation bed liners, and 6 mixed bed liners. The pref.ilter/
~ .
1 den 11neralizer and cation bed liners are 4' diameter by '4' high ~ cylindrical
~
vessels and the mixed bed liner is a 6' diameter by 6' high cylindrical vessel.
Since spent liners will be generated at a faster rate than they can be packaged and shipped off-site, due to limited shipping cask availability, they will be temporarily stored in an on-site facility and shipped as casks become available. An interim storage facility has been constructed for temporary on-site storage of spent liners until a larger concrete, weather-protected .
(from freeze-thaw cycles) f acility can be constructed (estimated completion is NovemDer 1,1979). The NRC on-site staff has provided design criteria ,
.~..^ _
- - . . . w: - ,
7 -
and guicance for both storage facilities from initial conceptual cesign to final cesign approval. For the interim storage facility, the staff pro-
. viced caily monitoring ano inspection of the construction activities to ensure conformance with design criteria.
5.2. On-Site Storage of Solid Waste 5.2.1 The Interim Storage Facility An interim storage facility has been constructed in the Unit 2 cooling tower desilting basin whicn can provide shielder storage for 28 spent
. liners from the operation of EPICOR-II. The fa.ility is located inside .
,~
the diked area of the station and is protected against the station design basis flood (l',100,000 cubic feet per second of river flow). The facility consists of sixteen cells 4.5' in diameter by 8' high and twelve cells 7' .
in diameter by 8' high. The smaller diameter cells are sized to accommodate spent prefilter/demineralizer and cation demineralizer liners from EPICOR-II ano the larger diameter cells are sized to accommodate the spent mixed bed
- liners from EPICOR-II. _The cells consist of galvanized corrugated metal
- cylinders' which have been provided with welded steel plates to act as a base. The base plates are painted on the outside surface to inhibit metal corrosion and the cylinder / plate weld joint was epoxied for the same purpose. The insice surface of the cell is coateo, up to a height of several feet, with a special paint that permits the surface to be '
easily decontaminated. In adoition, each cell is provided with a galvanized drip pan in which the liner is placed to collect any leakage or arippage. The leak integrity of the liner, the cells and the drip pan will prevent migration of radioactivity from the liners to the groundwater.-
In addition to that protection, a well will be drilled in the proximity of the storage facility which will De monitored to assure that no activity
. migrates from the liners to the groundwater. The cells are placed on
-ccmpacted, earthen.filldrLthe Uni;t 2 'oesiltiiig~ oa~siri and back.fj,lled, with ~
L - Icoinp ac'ted "Ea rtW t'o 'p rovi de' ~s ta'bi li ty'and 3ni e l dfig"for "the Tel'Ts .~hThe area 3 around the cells is provided with a gravel base and topped with several
! inches of asphalt. The area around the cells is also graded to cirect
- rain water away from the cells. Each cell is provided with a 16-toc rectangular concrete shield plug (3' thick). The storage cell and plug are designed to limit the contact dose rate to 5 mrem /hr or less. All transfers of spent liners into and out of the storage cells, including removal of and placement of the shield plugs, will be made with a mobile l crane (100-ton capacity with 110' ooom) which is dedicated to the facility.
I i C NNI.dieNbn's~iIce'ieIditleiif'fEdEdfMropp'in~glof7a91Tndr'inMhNi nfsYim stoYitleT 55" 9 %@@fhcMGQTh e4aci ol ogi c al-e ffectuofitll sMcciWn t,w H hbeethersame7as %=r#K mem inIne ' liner:oropraccidentnin Secticir3 A.' ~ - - - - -
- - - - ~
l r
)
I
_19 _
and guiuance for both storage facilities from initial conceptual cesign to final design approval. For the interim storage facility, the staff pro-
. vided caily monitoring ano inspection of the construction activities to ensure conformance with design criteria.
.5.2 On-Site Storage of Solid Waste 5.2.1- The Interim Storage Facility An interim storage facility has been constructed in the Unit 2 cooling tower desilting basin whicn can provide shielder storage for 28 spent l liners from the operation of EPICOR-II. Se fa.ility is located inside .
the diked area of the station and is protected against the station design basis flood (1,100,000 cubic feet per second of river flow). The facility consists of sixteen cells 4.5' in diameter by 8' high and twelve cells 7' .
in diameter by 8' high. The sr. aller diameter cells are sized to accommodate spent prefilter/demineralizer and cation demineralizer liners from EPICOR-II ano the larger diameter cells are sized to accommodate the spent mixed bed liners from EPICOR-II. The cells consist of galvanized corrugated metal cylinders' which have been provided with welded steel plates to act as a base. The base plates are painted on the outside surface to inhibit metal corrosion and the cylinder / plate weld joint was epoxied for the same purpose. The insiae surface of the cell is coatea, up to a height of several feet, with a special paint that permits the surface to be '
easily decontaminated. In addition, each cell is provided with a galvanized drip pan in which the liner is placed to collect any leakage or orippage. The leak integrity of the liner, the cells and the drip pan will prevent migration of radioactivity from the liners to the groundwater.-
In addition to that protection, a well will be drilled in the proximity of-the storage facility which will De monitored to assure that no activity migrates.from the liners to the groundwater. The cells are placed on y_ .
compacted. earthen f.il.1 iq_the _U_ nit 2 ce. silting oasin and backfilled with f W
'compac'ted VaYtY to provi'de ~ stability and ' shielding for.the cells. The area around the cells is provided with a gravel base and topped with several inches of asphalt. The area around the cells is also graded to direct rain water away from the cells. Each cell is provided with a 16-ton rectangular concrete shield plug (3' thick). The. storage. cell and plug are designed to limit the contact dose rate to 5 mrem /hr or less. All transfers of spent liners into and out of the storage cells, including
, , removal of and placement of the shield plugs, will be made with a mobile F crane (100-ton capacity with 110' .coom) which is dedicatea to the facility.
.E We consioerea the effect of cropping of a liner in the interim'. storage :--
.A- Macility. The-faciological effect=of ;this accident.willTbe_the same as
.tne liner crop . accident in3ection '3A -
~~
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~ -
8
+
I
~
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5.2.2 The C'oncrete Storage Facility The concrete storage facility will be a modular structure with each moaule consisting of approximately 60 storage cells. The mocules will oe built on an as-needed basis. The module will be located in the proximity of the
. interim storage facility and sufficient space exists to construct up to six modules. The module design will resemble a rectangular-shaped con-crete tube with dimensions of 57' wide by 91' lon The module base will be 3' thick and walls will be 4'g by 19' thick high. shielding for required (i.e. less than 5 mrem /hr from all surfaces). Th.e concrete storage facility is also located in the diked protected areg of tie station and is protected from the station cesign basis flood. -
. In addition to the dike, the elevation of the structure will be sufficient to accommodate the station design basis flood. The module cells will ,
consist of concrete shielded, galvanized, corrugated steel cylinders with welded steel base plates. The cell dimensions will be 7' in diameter by 13' high. The top shielding for the cells will be 3' thick rectangular concrete plugs. The plugs will be needed to prevent rain water inleakage to the cells. The cell interior surface will De painted with a coating which will facilitate decontamination. The leak integrity of the liner ano the cells will prevent migration of radioactivity from the liners to the groundwater. In addition to that protection, the cell base plates will be provided with a drain line leading to a sump to collect washdowns or liner drippage. The sump will hold approximately 1000 gallons and will be equipped with level indication and alarm on high level. All liquids collected in the sump will be sampled and analyzed for radioactivity and processed as
. required (for example, through EPICOR-1). Non-radioactive sump water (for -
example, rain water) will be discharged through a radiation monitor to the station drainage system. The sump will be designed to the seismic criteria
- , _ . s_ of Regulatory Guide 1.143. The module will be serviced by the same mobile
, cr3ne,which,is. uti.lized for_the., interim _ storage f acility. .The modul.e will '
! "' be capable of housing one liner 6' in~ diameter by 6' ~high per cell or two' l
liners 4' in diameter by 4' high per cell, thus providing' considerable i flexibility in the storage scheme. All liner transfers into or out of the cell will be as described for the interim storage facility. The module will be designed to protect the stored liners from the freeze-thaw cycle and the sump will be protected from freezing. Shipment of liners to an approved burial facility will occur as licensed shipping casks become '
! ,available.
l
_- __ Fe consider.ed the effect of droppins of a liner in the concrete storage
gy_. . -facility 7 The~Faciologi' chi effset ofithis accident will'be' the'samee -- - - 73 ~~
m - - -- - ..
as -thatmiscussedcfor;the .~1iner:orop3ccident in Section~ 3- 4..- .
l
,m , .. ,. ,_ _ . _ _ , . . _
o ,
g 5 5.2.3 Packa'ging and Transportation of Solid Waste All solid waste from the operation of EPICOR-II will be packaged and transported in accordance with existing 00T and ilRC regulations (i.e.
49 CFR Parts 171-179 and 10 CFR Parts 20 and 71) to a licensed burial facility for ultimate disposition. Section V-E of the Final Environmental Statement (FES)12 for Three Mile Island fluclear Station, Units 1 and 2,
. provides a discussion of the potential hazards associated with the trans-
. port. of radioactive materials and estimates of the radiological impact to memoers of the general public. Section 5.4 of the Final Supplement (NUREG-Oll2) to the FES, dated December 1976, provides an update of this discussion. The planned shipmen) of packaged s; lid waste from the operation
.of EPICOR-II does not alter the a'iscussicfi of :ne radiological impact
, associated with the transportation of solid waste already provided in the FES and the supplement to the FES. ,
5.2.4 Burial of Solid Waste Section 5.4.3 of the Final Supplement to the FES provides a discussion of the environmental effects of the uranium fuel cycle, including Durial of solia waste. The planned burial of solid waste generated from the operation of EPICOR-II does not alter the discussion of tne impact associated with the burial of solid waste already provided in the supplement to the FES.
6.0 Alternatives to Water Processing and the Use of EPICOR-II There are .three basic alternatives for handling the TMI Unit 2 intermediate.
level radioactive waste water. One is transport of liquids offsite, a second is continued storage of liquid in TMI Unit 2 auxiliary building tanks, and the third is processing to clean the water for ultimate disposition. First, we considered the shipment of contaminated water directly off-site. Because of ,.the hazards involved, such as potential spillage due to transpor_tation accidents and shielding ; requirements, 'and because the' low level waste burial ~ '9
, grounds will not accept free liquid wastes for burial, the staff concludes l that packaged liquid wastes would not be an acceptable alternative, l
. The second alternative considered, the continued storage of water in either the TMI Unit 2 auxiliary building tanks or additional new storage tanks, would result, first of all, in a continued accumulation of occu-pational exposure in order to maintain the plant in a safe shutdown condition. The continued storage of liquid in the TMI Unit 2 auxiliary '
! _ building _ tanks _or in_a_acitional new storage tanks, represents a source 47 lof direct ano airborne radiation-torthe workers who must occupy-the -
TT Auriliary . building -to Jaaintain -theplant-in a safe shutdown condition r
' including such activities as taking samples, making plant mooifications, . A l,' operating the gaseous radwaste system, taking radiation surveys, performing 1
l L
4 j
mainte~ nance activities on system components, and decontaminating the affected areas of the entire building. The worker prcblems associated with water storage are exacerbated by required water movements due to water inleakage or the need to move water from one tank to another to provide surge capacity. The staff estimates this is presently resulting
, in an occupational. exposure of about 15 man-rems for each month this situa-tion remains in its present state. Furthermore, the inability to perform requireo maintenance activities in the auxiliary buidling has an ultimate,
. deleterious impact on releases of radioactive materials in gaseous effluents i to the environment because of leakage from components which contain affected gas. Second, and more important, there is littic ' remaining surge capacity for additional liquid waste left ih the TM.E Uni: 2 tanks. As of July 3,.1979, a total of about 280,000 gallons of waste water nad been collected in TMI
. U' nit 2 tanks, leaving approximately 25,000 gallons of available surge capac-
, ity. (The surge capacity is the amount of tank storage capacity available to receive additional inputs). With daily water inleakage rates ranging
- from 0.2 to 1.0 gpm from components within the auxiliary building, the waste water inventories are increasing on a daily basis, further reducing the available surge capacity. If surge capacity is lost, this creates potential
~
problems such as tank overflows, system spillage, etc.. Available surge
. capacity is needed not only for daily inleakage, but also for receipt of
. containment building water, should the need arise for transfer. The level of water in the containment building is also rising (due to continuous component leakage) and poses .a threat to components in the lower
~e levations of the building. Should a contingency arise, some water in
. . the containment building may have to be transferred to available THI Unit 2 tankage to prevent the failure of components necessary for the continued s,afe shutdown and rehabilitation of the facility. .
Storage of water could be accomplished in additional new storage tanks, which would have to be constructed especially for this purpose, but i m- . these..new storage tanks would represent-a source of-occupational exposure ,
similar- totthat for--the Unittsuxiliary building tanks.. . In. addition,-
m.- .-- . 2 M the addition of new tanks would do little to relieve the imediate surge capacity problem discussed above since it would take a long period of time -
to construct tanks, and a building to house 'these tanks, which would meet the design criteria required for components to hold this radioactive l .. water. e The third alternative is processing the water to remove the radioactivity.
By processing the waste water in the auxiliary building tanks, the major gq.3. l.
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sourcs of direct and airborne radiation is removed ano chemically bound on an irr. mobile matrix (i .e. prefilter and resin material). Processing of waste water also reduces the likelihood of tank overflows (due to limited surge capacity) and subsequent transport of the contamina-tion to the environment. There exists three (3) options for processing the water:
- 1. Existing Radwaste Systems TMI Unit 2 water can be processed in the existing TMI Unit 1 or 2 radwaste systems. However, since these systus are not specifically designed for handling intermediate-level was ces, the systems are not capable of producing water of'suffici(nt qwlity for aischarge. In
, addition, .the overall recovery would likely be delayed since water recycling back through the syst:m would have to occur to achieve water capable of satisfying release requirements. The effects of -
the overall accident would be expanded to equipment and plant systems (Unit 1) not now exposed to the accident produced intermediate-level waste.
- 2. New EPICOR-II Radwaste System The new EPICOR-II Radwaste System is specifically cesigned to process intermeaiate-level waste and, therefore, it is capable of produci'ng discharge quality water by means of a proven technology (i .e., ion exchange methodology). The system is operational allowing a recovery sequence to proceed in an orderly, timely fashion. Although it is a newly constructed system, sufficient time is available to fully test it and demonstrate its operability, reliability, and operator proficiency.
- 3. New Radwaste Systems
' 7The mo's~t viableTalternative~ ts _a fi~ltratjon/ demineralization; process
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for the cleanup of intermediate-level waste is the process of evaporation and subsequent condensation of the distilled water. An evaporation process was rejected on the basis of the long lead time required to make the system available (at least six months). In addition, systems employing evaporators are not as reliable as filtration /cemineralization systems due to such evaporator problems as pump failure and tube failure, resulting in evaporator outages
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approximately 307, of the time.3 Thus, a system employing evaporators would be less efficient in reducing the large inventory M H= ;%4E ~ goffintermediate-levelywaste.g3asen.ongoperatingyperience4tather gg "
m.ma n m Z 77"J~.N. znplants,'cthe required auditionaT.
ZZaue7t'o' thNaporator maintenance. on.an~ ev~aporator system cutagesycul~diisJTtifiFhT{her'occup8henat
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-M exposures than for a filtration /cemineralizer systedi.~Speciil design provisions could mitigatge this cifference, however.
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5 It is 'therefore concluded that protection of the public health ano safety
, would be enhanced by the processing of the contaminatea water to the maxicum extent possible since imobilization of the activity currently held in the liquid would render this activity a less likely source of public or occupational exposure. It i's also concluded that the best alternative is _to process intermediate-level waste through a system specifically designed for that purpose, namely, the EPICOR-II processing
. system. The earlier the decision to proceed with water processing (irrespective of the method) is made, the less the total accumulated exposure, occupational and public, is likely to be. Once the water is removed from the auxiliary building tanks , the use resulting from the ultimate decontaminatien _of structure $and c amponents will De incurred regardless of the method used for proc:ssing of the water.
' 7.0 Evaluationofimpacts The processing of contari.inated waste by the EPICOR-II system will entail exposure to workers as described above and releases of small amounts of Xe-133 and I-131 to the environment. Occupational exposures of less than 5 man-rem constitute about 1 percent of the anticipated man-rem exposure for one year of normal facility operation. Off-site exposure is expectea to be less than one mrem which is well within applicable NRC and EPA guicelines. -
Since the major source of direct and airborne radiation in the auxiliary building will be removed by processing the intermediate-level waste water through EPICOR-II, the occupational exposure would be less than the exposure incurred by leaving the waste water in storage. Also, by processing the waste water to allow for component maintenance and oecontamination activities, the off-site releases in gaseous effluents can be reduced from current levels. Therefore, we conclude that the
.--' processing of the auxiliary building contaminated water through
& EPlCOR-II. will. not _have .an.. adverse impact and will .probably, lessen -
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.za the imp'act of th'e already contaminated water.
8 ,0 Summary Our evaluation supports the conclusion that the proposed EPICOR-II system is acceptable because:
- 1. The design of the EPICOR-II system meets or exceeds the guicance given in Regulatory Guide 1.143,1.140 and 1.21; ' '
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. sequences of this event show that they are insignificant;
- 3. The system design is such that releases of radioactive material in gasecus effluents will be insignificant;
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- 4. The design and operational considerations to minimize occupational exposure are consistent with the guidance given in Regulatory Guide 8.8; S. The occupational exposure due to system operation ano handling and storage of solid waste corresponds to less than 1 percent of the
, normal annual average for a nuclear power plant;
- 6. The dose at the site boundary due to direct radiation from the system operation and handling and storage 'of solid waste will be a small
, percentage of the limits of 40 CFR 190. .
Based on our estimate of gaseous r9) eases during operation of the EPICORE-II
, system, including a release due to an acciedntal spill, and our estimate of occupational dose and our estimate of direct radiation off-site, we con-
, ~clude that the operation of this system does not constitute a significant environmental impact. We further conclude that the health and safety of the public will not be endangered by operation of the system in the proposed
- manner and that such activities will be conducted in full compliance with
.' the Commission's regulations.
9.0. Conclusion We have determined, based on this assessment, that the proposed use of EPICOR-II for the processing of contaminated waste from the THI Unit 2 auxiliary building will not significantly affect the quality of the -
human environment. Therefore, the Commission has determined that an
, environmental inact statement need not be prepared, and that, pursuant to 10 CFR Sl.5(c), issuance of a negative declaration to this effect is appropriate.
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TABLE 1
.- RADI0 ACTIVE WATER VOLUMES FOR TMI UNIT 2 WHICH WILL BE PROCESSED BY EPICOR-II c, ,; YOLUME (gal',ons)
Reactor Coolant Bleed Tank A 77,250 Reactor Coolant Bleed Tank B 77,250 Reactor Coolant Bleed Tank C 77,250 tieutralizer Tank A 8,780 Neutralizer Tank B 8,780 .
Miscellaneous Waste Holdup Tank; Auxiliary Building Sump ana Sump Tank; Miscellaneous Sumps 13,500 f W{tsteEvaporatorCondensate '
%, FTanks;'-6dntaminated Drain *
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. Tanks 16,200 Fuel Handling Building Tanks 1.10,000 (Tank Farm) c .
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