ML20149J557

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Rev 0 to Preliminary Description for Accident Generated Water Disposal. W/One Oversize Drawing
ML20149J557
Person / Time
Site: Three Mile Island Constellation icon.png
Issue date: 02/16/1988
From: Cremeans G
GENERAL PUBLIC UTILITIES CORP.
To:
Shared Package
ML20149J552 List:
References
NUDOCS 8802230113
Download: ML20149J557 (25)
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PRELIMINARY SYSTEM DESCRIPTION FOR  !

t ACCIDENT GENERATED WATER DISPOSAL  !

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aw l Mpared 3y anageMicovery Engineering I 2-/4~88 .,

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1.0 PURPOSE. SCOPE AND ORGANIZATION 1.1 Purpose The purpose of this document is to describe the system and evolutions which will accomplish the controlled disposal of approximately 2.3 million gallons of "Accident Generated Water",

nereinafter referred to as processed water.

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The scope of this system description addresses the processing of this inventory by forced evaporation followed by a vaporization

! process and atmospheric release of the product distillate. It also .

includes the separation and final treatment of the solids removed t J .

and collected during the evaporation process and the preparation of the resulting waste product for shipment and burial at a commercial i'

low level waste facility, i i

1.3 Oraanization ,

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Section 2.0 describes the process and contains a system description of the evaporator, the vaporizer and the associated waste processing operations.

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Section 3.0 describes the control of process and the operational i options. t i

2.0 OESCRIPTION OF THE PROCESSED WATER OISPOSAL SYSTEM 2.1 Backaround i

The TMI-2 accident resulted in the production of large volumes of contaminated water, herein referred to as processed water. Through mid-1981, when the submerged demineralizer system (SDS) began operation to process water contained in the reactor building. l approximately 1.3 million gallons of water existed at TMI-2. Of this volume, about 640,000 gallons were located in the reactor l l building. Direct release from the reactor coolant system

j contributed 69% of this water. An additional 28% was river water introduced via leaks in Reactor Building air coolers and the remaining 3% was added via the containment spray system during the i

first several hours of the accident. Subsequent to 1981, most of l the water was processed by both SDS and EPICOR I! to reduce radionuelide levels to very low concentrations. In addition,

approximately 570,000 gallons of water existed in the auxiliary and fuel handling building tanks, most of which had been processed by EPICOR II by mid-1981. The reactor coolant system contained an 2

additional 96.000 gallons which also required processing by both 4

the SDS and the defueling water clean-up system (0WCS), Since

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the total inventory of processed water has increased to the

"'- it volume of approximately 2.1 Nillion gallons due to continued additions from support systems and condensation from the reactor building air coolers during the summer mortns.

Considerable care has been exercised to minimize the additions of new water and to ensure that the commingling of non-contaminated water with the processed water is restricted. Even with exercising care to minimize additions of new water, the final volume of water requiring disposal is expected to be 2.3 million gallons (as stated in Section 1.1).

l 2.2 process Descriotion The processed water dispcsal program consists of: (a) a dual evaporator system designed to evaporate the processed water at a ,

rate of five GPM; (b) an electric powered vaporizer designed to raise the evaporator distillate temperature to 240*F and release the resultant steam to the atmosphere via a flash tank and exhaust stack; (c) a waste concentrator designed to produce the final compact waste form, and (d) a packaging section designed to prepare the resultant waste for shipment consistent with commercial low level waste disposal regulations.  !? desired, the product distillate from the main evaporator can be routed to an interim staging tank for holding perposes, i.e.; to permit radiochemical analysis, batching evolutions and system shutdown, prior to being I

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1 routed to the vaporizer assembly for atmospheric release. The residual concentrate (bottoms) frG: the main evaporator section will be routed to the auxiliary evaporator for additional ,

processing and then to the final concentrator where it will be processed into the final compact waste form. The project will employ well proven technology and be continually monitored and controlled with automatic shutdown capabilities designed to terminate the vaporizer and atmospheric release process. With the exception of two controlled release points, one at the vapnrizer '

section, which will release the superheated steam to the atmosphere and the other at the waste processing section which will discharge the final waste to a collection point, the system will operate in a closed loop configuration. ,

l 2.3 System Description l'

The processed water disposal system consists of four pujor

component groups. They are
(1) the evaporator, (2) the P

vaporizer, (3) the blender / dryer concentrator, and (4) the waste r

e i preparation sections. (See Attachment 1., Process Flow Diagram) i t contract agreement was entered into with the selected vendor for ccnstruction of these four component groups and authorization was I

issued February 1988 to proceed to final design and fabrication of i

the eg:lipment for the specific TMI-2 application. Certain ,

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definitive design details necessary to prepare a comprehensive system description are not currently available as these final designs are an on-going ef f ort. The descriptive information that 3 is available and used extensively in the preparation of this system description is: (a) the vendor's contract proposal, (b) a system description for a unit similar to the one proposed for this l application, and (c) preliminary design information submitted.by the vendor January 1988 for review /coment by GPU. j i

Given these limitations, the following provides a general system description pending completion of the final designs.  ;

2.3.1 Gineral t

The main evaporator is a vapor recompression type unit with the ,

designed flexibility to be configured as a spraying film or climbing film evaporator. Vapor recompression units are designed f

to continually recycle the latent heat of vaporization (heat necessary to change water into steam) to sustain continued boiling at reduced pressures and therefore at lower temperatures.

The main evaporator employs a vapor dome, positioned over a r

horizontal tube heat exchanger, to collect the natural rising vapor l from the evaporator process. This vapor collection is through two 12 inch diametrically opposed uptake pipes which fcod an  !

entrainment separator housed within the dome. The entrained  !

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l water is screened by capillary action on the wires of two-stage mesh impingement screens that drain the separated solids to the bottom of the separator. There, the solids are extracted by the 4

recycle pump and routed to the concentrate tank. The vapor compressor, taking a suction on the vapor dome, superheats this dried vapor by the heat of compression and discharges the heated vapor down through the tube side of the 520 f t 2heat exchanger.

The vapor is condensed and then routed to the skid mounted distillate tank for ultimate vaporization and atmospheric release.

If desired, due to batching evolutions, system shutdown or d

radiochemical analysis, the distillate can be routed to an interim staging tank.

I The product concentrate, separated by the two-stage impingement

screens and collected in the concentrate tank, will be recycled j back through the main evaporator for further processing or, 1

j depending on the level of it: concentrate, routed to the settling tank for second stage treatment by the auxiliary evaporator. The i second stage treatment consists of increasing the level of solids concentrate to 100,000 to 500,000 ppm by forced evaporation in the '

auxiliary evaporator section which is similar in design and employs d the same method of solids separation as the main evaporator.

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The increased concentrate from this separation process is collected at the bottom of the auxiliary evaporator separator where it is extracted by the second stage recycle pump and returned to the settling tank. This increased concentrate will be recycled through the auxiliary evaporator for further processing or, depending on~

the solids concentrate level, extracted by the concentrate feed pump and routed to the blender / dryer section via the concentrate holding tank for final treatment prior to packaging operations.

2.3.2 Evaporator The principle utilized in a high vacuum vapor compressor distiller concentrator is similar to the refrigeration cycle except for the use of water as a refrigerant. As the system pressure is reduced, so is the boiling point of the product solution. Therefore, rapid evaporation takes place at a lower temperature and the latent heat of vaporization (heat reces'idry to change water into steam) can be continuously recycled by the use of a vapor compressor.

Vapor recompression evaporation requires steam heat to initiate start-up and occasional supplementary heat to make up for heat losses during operation and feed heating requirements. This auxiliary start-up and supplementary heat will be provided by the auxilie r, evaporator which is designed to raise the start-up teraperature to approximately 131*F. Once started, the main l

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1 evaporator will boil the processed water under a vacuum on the shell side of tne heat exchanger tubes at temperatures of 130* to 140*F. The excessive evaporator feed, that feed above the designed-rate of evaporation, will combine with the vapor generated and exit from the shell via twin 12 inch uptakes to the separator.

The foaming tendency of the water during this process will completely "wet" the tubes and the resultant vapor being generated will be in the form of minute vapor bubbles. This action prevents the formation of large vapor bubbles which would insulate the tubes, raise the hydrostatic head and reduce heat transfer rates.

The evaporator twin uptakes, diametrically opposed, discharge the >

larger water particles of the excess feed to the bottom of the  ;

sepa rator. Any fine mist carried upward by the vapor, impinges on the two-stage mesh where it coalesces and drops to the bottom of  ;

the separator for extraction and recycling by the concentrate recycle pump. This feed and bleed action not only assures continuous wetting of the heat exchanger tubes, it provides the maximum concentration of the liquid for discharge to the auxiliary evaporator for additional processing.

The compressor action is described in Paragraph 2.3.4. The i superheated vapor from the vapor compressor is discharged down through the annulus between the 1 inch titanium sheaths of the heat exchanger where the vapor is condensed by the evaporating action l

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from the processed boiling water. The condensate (distillate) is propelled to the back end of the titanium sheaths where it is sucked out through 1/4 inch stainless steel tubes and discharged to the distillate collection tank.

2.3.3 VaDorizer The vaporizer section takes a suction from the product distillate supply. It is used to raise the product distillate temperatures to approximately 240*F under pressure, release the heated distillate to atmospheric pressure via a flash tank and exhaust the resultant steam through a 100 foot high stack. The vaporizer assembly consists of: (a) three, 300 (KW) heaters used to elevate the distillate temperature to 240*F at 10 psig; (b) a 24 inch diameter by 60 inch high stainless steel flash tank, used to expose the 240*F distillate to atmospheric pressure and to contain the resultant steam; (c) a 7-1/2 HP pump, used to recirculate the distillate in the flash tank through the heaters; and (d) a 3 inch diameter by 100 foot high stainless steel exhaust stack, used to release the steam at a velocity of approximately 350 feet per second. The exhaust stack will be equipped with a sound abatement dampener to modulate the sound levels during exhaust operations.

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2.3.4 Vapor Compressor The vapor compressor is designed to take suction from the vapor dome af ter the vapor has been dried by passing through the two-stage mesh separators. Flexiole expansion joints will be incorporated to relieve any strain on the compressor housing. The rotary lobe compressor is a positive displacement blower with a capacity of about 5230 CFM at full load speed of 1750 rpm on the 125 HP compressor motor.

Its designed application is to take suction on the rising vapor, heated by the latent heat of vaporization being collected in the vapor dome, and compress the vapor to create a rise in temperature due to the heat of compression. This superheated vapor is then discharged into the tube side of the evaporator heat exchanger.

2.3.5 Auxiliary EvaDorator A small waste heat auxiliary evaporator using heat generated f rom the before and after electric heater (s) and/or the 143*F product distillate from the main evaporator, will evaporate the product concentrate from the main evaporator at an approximate temperature of 130*F. The vapor from the process will be routed to the main evaporator vapor dome to provide supplementary or start-up heat to the main evaporator. The increased concentrate (bottoms) f rom the 10 0078H/3H

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-i auxiliary evaporator will be extracted by the recycle pump and l routed to the settling tank. The concentrate will be recycled through _the auxiliary _ evaporator and the settling tank until the level of concentrate is between 100,000 and 500,000 ppm at which time the a feed pump will take suction on the settling tank and route the concentrate to the concentrate holding tank.

2.3.6 Blender / Dryer The blender / dryer will process the concentrate collected in the l t

concentrate holding tank to the final waste form in s httch type i process. The blender / dryer consists of a cylindrical, horizontal vessel equipped with an agitator for drying liquids and slurries to  !

total dryness. The dryer body will be equipped with a 150 KW electrically heated jacket. The liquid in the waste slurry will be evaporated as it comes in contact with the heated body of the [

vessel as the agitator moves the waste slurry from both ends of the t

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, dryer vessel toward a center discharge valve. The agitator -

consists of rotating helical ribbons which continually scrape the [

, dried product f rom the sides of the vessel and move the waste product to a center discharge valve. The drying process is f controlled so that the waste batch is discharged when the liquid is I t

removed, at which time the final waste product will be discharged

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directly into the collection section for packaging preparations.  !

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The liquid from the dryer section will be returned to the main evaporator concentrate tank and reprocessed.

2.3.7 Packaging Waste packaging options' permit packaging by one of three methods,  ;

i the selection of which is left to the discretion of the vendor.

All options are acceptable methods, relative to applicable f regulations, and all employ satisfactory volume reduction tecianiques. In the event a binder agent is required, to minimize ,

the dispersion factors involved in calculation of release fractions I during a postulated median transportation accident, its addition will not appreciably increase the estimated volume of waste ,

generated as a result of any of these options. Option 1 utilizes a ,

pelletizer to compact the waste into a pelletized form and then i discharges the compressed product into a Spec.17, 55 gallon transport drum. Option 2 discharges ti:a waste product directly f rom the dryer into a 55 gallon drum, compacts the drum (and -

product) to a fraction of its original volume and loads the i compacted drum into a transportation over-pac container. Option 3 .

discharges the waste product directly into a Spec. 17, 55 gallon i i

transport drum and loads the drum, uncompacted, into a j

transportation over-pac container. i l

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The volume of waste generated as a result of any of these techniques is estinated to be 4400 to 4500 ft . 3 This volume T

represents a significant reduction to the estimated waste volume presented in the PEIS Supplement 2 which used as the method of 3

waste packaging solidifying the waste in 170 ft liners.

The base case presented in the PEIS Supplement 2, which addresses the solidification of waste with Portland cement in 170 ft 3 liners, provides a waste volume estimate of between 27,000 to 46,000 ft , for 25 wt. % solids and 16 wt. % solids respectively, assuming i. 0.35 cement to waste volume ratio. The base case further estimated that in the event of chemical impurities retarding the curing rate and final strength of the concrete the projected volume of solidified waste could be as high as 3

88,000 ft ,

2.3.8 Instrumentation The system design will provide conductivity monitoring at three independent system locations during the evaporator process. Each of these monitoring points will be equipped with a sample point station for the extraction of pricess fluids for radiochemical i r.nalysis and a conductivity probe for the steady state monitoring '

of process liquid quality. These monitoring locations are at the '

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main evaporator feed and at the main and auxiliary evaporator distillate discharge. Additionally, there will be a sample station located at the auxiliary evaporator concentrate discharge for concentrate sampling and a conductivity probe and sample station at the radiation monitor.

Operational experience and an accumulated data base accrued during actual evaporator operations will provide a sound basis for comparing these two methods of analysis, i.e., physical sampling with laboratory analysis and steady state conductivity monitoring.

Af ter adequate demonstration of comparable analytical results and conductivity data, operational procedures may be modified to rely i l

more extensively on the steady state conductivity instrumentation.  ;

However, until a data base can be compiled based on actual system  ;

operations, the control method utilized in procedures and operating programs will be the physical sampling and laboratory analysis of l process liquids. Radiation monitoring of the vaporizer influent will continue to be the essential method of process control of environmental release by the vaporizer assembly.

The vaporizer section of the system, which releases the vaporized i

distillate into the atmosphere, will be monitored and controlled by )

a gamma radiation detector. This detector, located in the vaporizer assembly flow path, will monitor levels of gamma radiation in the distillate prior to the distillate being routed to l l

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the vaporizer heaters. The detector will be calibrated to sound an audible alarm and terminate atmospheric release by tripping of f the vaporizer heaters and/or initiating valve closure to isolate the distillate supply to the vaporizer section. In the event an alarm condition occurs, the evaporator will continue to operate in a batch cycle mode, discharging the product distillate to a staging tank or recycling it through the system until the system is secured or the alarm condition is removed. The pre-determined set points of the radiation detector are based on insuring the present THI-2 Technical Specification instantaneous release limit of 0.3 uC1/sec. will not be exceeded. Monitoring equipment is available which will allow a setpoint at 25% of this instantaneous release rate limit for particulates which is 7.5E-2 uC1/sec.

Assuming the gamma emitting isotope Cs-137 is at a concentration of 3.7 E-8 uCi/ml., the level of concentration permissible for continuous release per Table 3-1 and the PEIS Supplement 2, is present in the vaporizer influent then a corresponding maximum continuous release rate of 4.8E-4 uC1/sec. for all the radionuclides is also present. This is the permissible rate of cnntinuous release as bounded by the PEIS Supplement 2.

This ratio of Cs-137 concentration to the maximum permissible continuous t elease rate yields a scaling factor of 1.32E-4. using this scaling factor and the determined instantaneous release rate 15 0078H/3H

of 7.5E-2 uCi/sec., which is 25% of the-Technical Specification maximum instantaneous release rate, it can be calculated that the Cs-137 concentration of 9.9E-6 uCi/ml. is the permissible limit for controlling the rate of instantaneous release.

(1.32E-4 X 7.5E-2 = 9.9E-6).

State of the art instrumentation will be installed which is capa41 1 of detecting this level of Cs-137 although it will be unable to detect minor variations in the extremely small quantities of most isotopes present. (Table 3-1 notes that 22 isotopes are expected to be present at levels <LLD). Others are of such small quantities as to be a small f raction of the Technical Specification limits. Therefore, this monitor is expected to detect "gross upsets" and terminate releases to the environment before the Technical Specification release limits are exceeded.

Conservatively, assuming a 100% carryover of the particulate content through the vaporizer, radioisotopic content of the influent to the vaporizer (i.e., the evaporation distillate) is the process control mechanism and will be additionally controlled by sampling and conductivity monitoring. It is note worthy that the radiation alarm set point is approximately the same as the limit for the average Cs-137 concentrations permissible in the evaporator influent. Thus, the set point limit of the detector provides reasonable assurance that the evaporator is not by-passed.

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i TABLE 3-1 l l 1

> 1 VAPORIZER INFLUENT CRITERIA  !

l Continuous Release (l)

Quantity Concentration Constituent C1 uCi/mi Tritium (Hydrogen-3) 1.02 x 103 1.3 x 10-1 Cesium-137 3.2 x 10-4 3.7 x 10-8 Cesium-134 7.66 x 10-6 8.8 x 10-10 Strontium-90 9.6 x 10-4 1.1 x 10-7 Antimony-125/

Tellurium-125m 2.0 x 10-5 2.3 x 10-9 Carbon-14 8.7 x 10-4 1.0 x 10-7 Technetium-99 8.7 x 10-6 1.0 x 10-9 Iron-55 4.2 x 10-6 4.8 x 10-10 Cobalt-60 4.2 x 10-6 4.8 x 10-10 Boron 0.15 tons H 3B03 3.0 ppm B Sodium 0.011 tons NaOH .7 ppm Na*

  • Iodine-129 <5.2 x 10-3 <6.0 x 10-7
  • Cerium-144 <1.4 x 10-5 <1.8 x 10-9
  • Cobalt-58 <3.5 x 10-7 <4.0 x 10-11
  • Nickel-63 <5.2 x 10-6 <6.0 x 10-10
  • Zinc-65 <8.5 x 10-7 <9.8 x 10-11
  • Ruthenium-106/

Rhodium-106 <2.9 x 10-6 <3.3 x 10-10

  • Silver-110m <4.9 x 10-7 <5.6 x 10-11
  • Promethium-147 <4.2 x 10-5 <4.8 x 10-9
  • Eu ropium-152 <3.3 x 10-9 <3.8 x 10-13
  • Europium-154 <3.8 x 10-7 <4.4 x 10-11
  • Eu r opi um-155 <9.6 x 10-7 <1.1 x 10-10
  • Uranium-234 <8.7 x 10-8 <1,0 x 10-11
  • Uranium-235 <1.0 x 10-7 <1.2 x 10-11
  • Uranium-238 <1.0 x 10-7 <1.2 x 10-11
  • Plutonium-238 <1.0 x 10-7 <1.2 x 10-11
  • Plutonium-239 <1.2 x 10-7 <1.4 x 10-11
  • Plutonium-240 <1.2 x 10-7 <1.4 x 10-11
  • Plutonium-241 <5.7 x 10-6 <6.5 x 10-10
  • Curium-242 48.7 x 10-7 <1.0 x 10-10 Totals Concentration (Average): 2.61 x 10-7 uCi/ml.

Continuous Rate of Release at 5 GPM: 8.i3 x 10-5 uCi/sec.

  • Denotes assumed constituents

< Denotes less than level of detection (1) Release concentration average over any calendar quarter.

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i TABLE 3-2 I

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[RN lNU)!!b CYCLE EVAPORATOR INFLUENT / EFFLUENT CRITERIA l I Influent i Effluent I I I l l Quantity Concentration l Quantity Concentration I Constittent I Ci pCi/ml l C_i, pC1/m1 l i i  !

Total voluee  ! 2,300,000 gal. l i

l i Tritium l l

( Hyd roger.-3) l 1.02 x 103 1.3 x 10-1 l 1.02 x 103 1.3 x 10-1 Cesium-137 1 3.2 x 10-1 3.7 x 10-5 1 3.2 x 10-4 3.7 x 10-8 .

Cesium-134 l 7.66 x 10-3 8.8 x 10-7 l 7.66 x 10-6 8.8 x 10-10 l St roritiam-90 l 9.6 x 10-1 1.1 x 10-4 l 9.6 x 10-4 1.1 x 10-7 Ardimony-125/ l l Tellurium-125m i 2.0 x 10-2 2.3 x 10-6 1 2.0 x 10-5 2.3 x 10-9 Ca rt.on -14 1 9.7 x 10-1 1.0 x 10-4 l 8.7 10-4 1.0 x 10-7 Tecnaetium-99 i 8.7 x 10-3 1,0 x 10-6 l 8.7 x 10-6 1.0 x 10-9  !

Iron-55 i 4.2 x 10-3 4,8 x 10-7 l 4.2 x 10-6 4.8 x 10-10 Coonit-60 1 4.2 x 10-3 4.8 x 10-7 l 4.2 x 10-6 4.8 x 10-10 Boron l 150 tons 3000 ppm 8 l .15 to is 3.0 ppm B l H3803 I H3803 Sodium l 11 tons MACH 700 ppm Na+ l .011 tons ita0H .1 ppm Nat

  • Iodine-129 l<5.2 x 10-3 <6.0 x 10-7 (<5.2 x 10-3 4 6.0 x 10-7
  • Cerium-144 l<1.4 x 10-2 <1.8 x 10-6 l<1,4 x 10-5 < 1,s x 10-9
  • Manganese-54 l<3.5 .s 10-4 <4.0 x 10-8 l<3.5 x 10-7 < 4.0 x 10-11
  • Cobalt-58 (<3.5 x 10-4 <4.0 x 10-8 l<3.5 y 10-7 < 4.0 x 10-11
  • Nickel-63 l<5.2 x 10-3 <6.0 x 10-7 i<5.2 x 10-6 < 6.0 x 10-10
  • Zinc-65 l<8.5 x 10-4 <9.8 x 10-8 (<8.5 x 100 < 9.8 x 10-11
  • Ruthenium-106/ l l Rhodium-106 l<2.9 x 10-3 <3.3 x 10-7 l<2.9 x 10-6 < 3,3 x 10-10
  • Silver-110m (<4.9 x 10-4 <5.6 x 10-8 l<4.9 x177 < 5.6 x 10-11
  • Promethium-147 l<4.2 x 10-2 <4.8 x 10-6 l<4.2 x 'O'6 < 4.8 x 10-9
  • Europium-152 l<3.3 x 10-6 <3.8 x 10-10 l<3,3 x 19-9 < 3.8 x 10-13
  • Europium-154 l<3.8 x 10-4 <4.4 x 10-8 l<3.8 x 16-7 < 4,4 x 10-11
  • Europium-155 i<9.0 x 10-4 <1.1 x 10-7 i<9.6 x 10-7 < ) .1 x 10-10
  • Uranium-234 l<8.7 x 10-5 <1.0 x 10-8 i<8.7 x 10-8 < 1,0 x 10-11
  • Uranium-235 l<1.0 x 10-4 <1.2 x 10-8 i<1.0 x 10-7 < 1.2 x 10-11
  • Uranium-238 l<1.0 x 10-4 <1.2 x 10-8  !<1.0 x 10-7 < 1,2 x 10-11
  • Plutonium-238 l<1.0 x 10-4 <1.2 x 10-8 l<1,0 x 10-7 < 1.2 x 10-11
  • Plutonium-239 l<1.2 x 10-4 <1.4 x 10-8 l<1 , x 10-7 < 1.4 x 10-11
  • Plutonium-240 l<1.2 x 10-4 <1.4 x 10-8 l<1.2 x 10-7 < 1.4 x 10-11
  • Plutonium-241 l<5.7 x 10-3 <6.5 x 10-7 l<5.7 x 10-6 < 6.5 x 10-10
  • Americium-241 l<1.0 x 10-4 <1.2 x 10-8 l<1.0 x 10-7 < 1.2 x 10-11
  • Curium-242 l<8.7 x 10-4 <1.0 x 10-7 l<8.7 x 10-7 < 1.0 x 10-10 Effluent Totals  ;

Particulate Concentration: 2.61 x 10-7 uCi/nl. i Continuous Rate of i Particulate Release at 5 GPM: 8.23 x 10-5 uCi/sec. ,

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< Oenotes less than level of detection 18 0078H/3H 1

s 3.0 PROCESS CONTROL AND OPERATIONAL OPTIONS 3.1 Process Control The process control of atmospheric releases during the evaporator.

and vaporization process will be implemented via the radiation monitoring and radiochemical sampling of the influent to the vapor 12er section. Establishing process control at the vaporizer influent conservatively assumes a 100% carry-over f raction through the vaporizer assembly. There is no credit for plate out or solids separation in the heaters, flash tank or exhaust stack.

To establish a basis for this influent acceptability the criteria established in Section 2.0 of the PEIS Supplement II was used as a basis for comparison of the radiological constituents 3nd respective concentrattoes acceptable for release to the atmosphere during operation of the vaporiter assembly. The average influent ,

to the vaporizer as;cobly, noted in Table 3-1 is approximately 2.61E~i 9Ci/141 This concentration, discharged at a rate of 5 GPM limits the ceasinuous release of non-tritium radioactive material, prantipally cesien~)37, strantium-90, and carbon-14 to approximately 9,73f,-5 ,C4/sec, This rate is less than 0.4% of the continuaas porticciate release rate ce.'mitted by the TMI-2  ;

Recovery 7t=,nnir.a1 7pec6tications (0.064 uCi/sec.) when averaged

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over any calendar quarter. It is als6 less than the rate of release sto+ed in the PEIS Supplement II, section 3.1.1.2 (0.00028 pCi/sec. (2.8 E-4)) which was c41culated at a flow rate of 20 GPM.

The radionuclides and their permissible le. of concentrations as influent to the vaporizer assembly for atmospheric ~ release are listed in Table 3-1. This table conservatively assumes that certain radionuclides, not positively identified in the process water samples, nevertheless exist at the stated lowest limit of detection. These assumed radionuclides, identified by an asterisk, are included in the table.

3.2 Operationai Options The designed flexibility of the evaporator / vaporizer erJipment i

permits the evaporator assembly to be de-coupled from the vaporizer assembly. In this configuration, the evaporutor operates independent of the vanorizer and processes the water in a catch cycle method of operation. Conversely, if the' vaporizer is coupled to the evaporator during operations, the water will be procossed in a continuous type method of operation. The operational options addressed in this section describe these two methods of process operations. l I

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6 3.2.1 Batch Cycle Operations _

In this configuration, the evaporator asse;nbly will process water independent of 1:he vaporizer assembly.,  ?,he product distillate from the evaporator will be collected in a staging tank for scmpling and radicchemical analysis. The benefits realized by this operational method are primarily in the area of radiological waste volume and occupational exposure reductions. By using the evaporator assembly as a pretreatment technique for certain of the volumes of water,  ;

i pretreatment by one of the ion exchange systems and the resulting '

contamination of demineralizer resins wecJld be eliminated. Thus, .:

?

the handling and shipping of the resin . linen for disposal purposes is (Oiminated.

The collected product distillates, sampled at the staging tank, will ce radiochemically analyzed for compliance with the controlling concentrations noted in Tables 3-1 or 3-?. Process operations by the evaporator coupled to the vcporizer assembly or by the vaporizer assembly independent of the evaporator, will not be peraitted until after it has been analytically determined by NRC approved process control procedures that the controlling ,

c'snstituents of the distillate are at or below those levels of concentrations noted in the influent column of the applicable table, (i.e., Table 3-1, vaporizer influent criteria, and Table 3-C, continuous cycle evaporator influent criteria).  !

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N 3.2.2 Continuous Cvele Operations In this configuration, the evaporator and vaporizer assemolies will be coupled and operate as a continuous cycle unit. The control of

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this operation will be initially established by the isolation of the body of water scheduled for continuous cycle' evaporation. Once this isolation is complate, a physical radiochemical analysis will be performed on the water and compared to the controlling radioactive constituents noted in Table 3-2. Process operations by the evaporator and vaporizer equipment will not be permitted until ,

after it has been analytically determined by NRC approved process control procedures that the controlling constituents are at or below those levels of concentration noted in the influent column of 1

the table.

The imposition of these evaporator influest limits coupled with a conservative carry-over f raction of 0.1% assumed during evaporator operations, will assure that the rate of atmospheric release of ,

particulate radioactive material will be in compliance with the permissible release concentrations established in Section 3.1. i Operational experience and historical data accrued during actual operations (i.e., batch and continuous cycle operations) will provide a sound basis for the continued use of a 0.1% carry-over i f raction for operational limits. Development of an operational l

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data base using physical sampling and radiochemical analysis may demonstrate that a less conservative carry-over fraction may be applied and the cperational procedures modified accordingly.

However, until compilation of this data base during actual system.

operations, the 0.1% carry-over fraction will be assumed as the procedural control limit.for continuous cycle operations.

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