ML20247L068
| ML20247L068 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 09/11/1989 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20247L024 | List: |
| References | |
| NUDOCS 8909220105 | |
| Download: ML20247L068 (5) | |
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UNITED STATES I
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l SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 35 TO FACILITY CPERATING LICENSE NO. DPR-73 GPU NUCLEAR CORPORATION THREE MILE ISLAND NUCLEAR STATION, UNIT NO. 2 DOCKET NO. 50-320
1.0 INTRODUCTION
GPU Nuclear Corporation (GPUN, the licersee) submitted a proposal to dispose of 2.3 millior gallons of accident generated water (AGW) stored at Three Mile Island, Unit 2 (THI-2) using an evaporation process. Accident generated water is defined as:
a.
Water that existed in the TMI-2 Auxiliary, Fuel Handling, and Containment Buildings including the primary system as of October 16, 1979, with the exception of water which as a result of decontamination operations becomes commingled with non-accident generated water such that the comingled water has a tritium content of 0.025 uti/ml of tritium or less before processing; b.
Water that has a total activity of greater than one uC1/ml prior to processing except where such water is originally non-accident water and becomes contaminated by use in cleanup; c.
Water that contains greater than 0.025 uCi/ml of tritium before processing.
The NRC. staff, in response to the licensee's February 25, 1987 (revised April 13, 1987) application for a change in the TMI-2 technical specifications to allow the disposal of the AGW, prepared Final Supplement 2 to the Programmatic Environ-mental Impact Statement (PEIS) related to decontamination and disposal of radioactive wastes resulting from the March 28, 1979 accident. Final Supple-ment 2 to the PEIS, issued in June 1987, evaluated the licensee's proposal to evaporate the AGW as well as a number of alternatives. A Notice of Consideration of Issuance of Amendment and Opportunity for Hearing in connection with this action was published in the FEDERAL REGISTER on July 31, 1987 (52 FR 28626).
A hearing before an Atomic Safety and Licensing Board Panel (ASLBP) was held in November 1988. On February 2,1989 the ASLBP issued a final initial decision finding in favor of the licensee in all relevant matters and recommending that
- the requested amendment to the license be authorized. On April 13, 1989 the Comission affirmed the Licensing Board's February 2,1989 decision and determined that the license amendment would be effective imediately upon issuance by the NRC staff. The Comission found no reason to stay the effectiveness of-the Licensing Board's decision pending completion of the appeals process.
6909220105 890911 PDR ADOCK 05000320 r-F DL.
, GPUN submitted a system description (reference b), a technical evaluation report (reference c) and additional supporting documentation (ref d and e) in response to NRC staff requests for further information (reference f and g) as a result of the staff's detailed review of the processed water disposal system.
2 DESCRIPTION OF THE EVAPORATOR SYSTEM The processed water disposal system has two subsystems the evaporator subsystem and the packaging subsystem.
The evaporator subsystem actually contains four separate components which change water from the aqueous to a vapor form. Two of these components are designated as evaporators, one as a dryer, and the final one is designated as a vaporizer. Water to be evaporated is routed to a source or feed tank where it is sampled and analyzed to verify proper influent specifications.
This influent water will have an average influent concentration of approximately 4000 ppm of solids, principally boron and sodium. The influent water then passes through a vapor-recompression vaporizer. The distillate from this process will normally have achieved a decontamination factor (DF) of 1000 or greater.
During initial operations the distillate will be routed to a distillate tank for sampling and analysis to verify that the required DF has been achieved.
The water will then be pumped through a vaporizer where it will be heated under pressure then fl.shed to steam. After verifying that boron' concentration in the distillate can be used to monitor DF, the licensee may use a coupled mode in which the distillate will go directly to the vaporizer. The concentrated solution, (bottoms) containing about 5-10 times the dissolved solids content of the influent is continuously recirculated through the concentrate tank. A portion of the recirculating concentrate is continuously drawn off to feed an auxiliary evaporator and auxiliary concentrate tank for further concentration.
The distillate from the auxiliary evaporator will be returned to the main evaporator system. The bottoms from the auxiliary concentrate tank which will be in the 20-40% solids concentration range will be sent to a dryer and pelletizer. The dryer uses electrical strip heaters to dry the incoming liquid or slurry. The vapor from the dryer is condensed and the distillate returned I
to the main concentrates tank.
The dry solid waste from the blender / dryer is transferred to the second major subsystem of the processed water disposal system the packaging subsystem.
The solids are discharged to a pellet mill and extruded into solid pellets.
The pelletizer and drum filling station are in an enclosure which is maintained under negative pressure by a high efficiency particulate absolute (HEPA) filter system. The dried pelletized bottoms will be packed into 55 gallon drums and shipped by truck to the low leve i waste disposal grounds near Richland, Washington.
Final Supplement 2 to the PEIS assumed certain criteria for operation of processed water disposal system. Operating the system within the criteria provided by Supplement 2 would result in an acceptable level of impact.
These criteria pertained to the characterization of the influent AGW, the decontamination factor of the disposal system, the system inventory of AGW at any given time (for estimating the potential impacts associated with accidents) and the characteristics of the evaporator bottoms and the associated shipping campaign (for estimating impacts associated with processing, packaging, and shipment of the evaporator bottoms).
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3.0- EVALUATION The technical issues concerning the evaporator system are:
1.
Preprocessing of water to achieve the base case radionuclides-concentrationsdescribedinPEISSupplement2(referencea).
2.
The. ability of the evaporator system to achieve a decontamination factor (DF) of 1000 while processing base case water.
3.
The ability of the licensee to monitor effluents from the process stack and the building ventilation during routine and off normal conditions.
4.
Potential accidents associated with the use of the evaporator.
5.
Potential for any safety problems in the transporting of evaporator bottom to tha LLW disposal site.
The licensee has several systems which could be used alone or in combination as a preprocessor to achieve the base case assumed in PEIS Supplement 2.
These include the EPICOR system, the Submerged Denineralizer System (SDS, which would have to be reactivated prior to use), the defueling water cleanup system (DWCS), and the evaporator system itself in a closed cycle mode. Verification that preprocessing has achieved base case or lower concentrations is easily confirmed by the licensee's sampling program. Samples will be taken and analyzed after preprocessing prior to using the water as a feed source to the evaporator system. The staff is satisfied that the licensee has adequate resources available to achieve and verify base case (or better) feedwater to the evaporator system.
The staff has evaluated GPUN's system description (reference b), technical evaluation report (TER), (reference c), evaporator test report, (reference h) and the supplemental information on the TER (reference f). The staff has concluded that the evaporator system is capable of achieving a DF of 1000 or greater in the feed.to the vaporizer. This determination is based on a detailed review of the system, the results of surrogate AGW testing by the manufacturer, and the ability of the licensee to change the processed control system to vary the DF. GPUN has satisfactorily described a program which will use boron i
concentrations and effluent samples to control the process such that the required average DF is being achieved. Alternate control methods may prove more advantageous after the licensee completes an additional onsite testing program using a non-radioactive surrogate. The staff finds it acceptable to use alternate control systems provided that they are either incorporated in procedures subject to NRC review and approval or a revised description is submitted to the NRC in licensing basis documents.
- The licensee's process and effluent monitoring system shall include a compositing sample on the vaporizer feed line and a continuous air monitor (CAM) in the process area near the building ventilation exhaust. GPUN radiological. controls personnel will evaluate the positioning of the CAM on a quarterly basis to assure that the results from this device conservatively represent the effluent from the building exhaust.
In the event that the compositing sampler or CAM become inoperable, grab ~ samples may be taken every 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> for up to 1 week.
If the sampling equipment is not returned to service within I week, the evaporator system shall be shut down. The licensee has the capability to measure routine and non-routine effluents from the evaporation process and from non-process sources such as maintenance and i
system leaks.
l The staff also evaluated potential accidents associated with the evaporator system. The source term in the accident generated water, which is fully described in PEIS Supplement 2 (reference a) is small and very dilute. Only a small fraction of the water and resulting solids would be in the process building at any time. Potential offsite dose consequences of liquid spills, dry spills and filter failure were evaluated by the licensee and the NRC.
In all cases, the rc=lts were less than 0.1 mrem. This is a small portion of 10 CFR 50 Appendix I objectives and very small in relation to 10 CFR 20 or 10 CFR 100 limits.
Transportation of the solidified evaporator bottoms was evaluated in PEIS Supplement 2 and an additional environmental assessment dated Radiation levels at 3 ft. from an individual 55 gallor, drum are expected to be less that 0.2 mrem / hour. The pelletized waste will be shipped in accordance with Department of Transportation (DOT) regulations. Routine exposure from the shipments was conservatively estimated to be 7.1 person-rem, approximately half of which is attributed to the truck crews. The probabilistic exposure risk from transportation accidents which integrates probability and outcome was 0.16 person-rem for the entire shipping program.
4.0 ENVIRONMEh. A' CONSIDERATION The staff fully considered the environmental consequences of the proposed action in Final Supplement 2 to the PEIS published in June 1987, and an environmental assessment and finding of no significant impact was published in the Federal Re01 ster on September 11, 1989 (54 FR 37517). Furthermore a hearing was he'd in November 1988 to further supplement the record on environmental considerations. The staff concludes that the proposed action will not have a significant effect on the quality of the human environment.
5.0 CONCLUSION
S The NRC staff has reviewed and evaluated the proposed use of the processed water disposal system to evaporate the accident generated water at Three Mile Island Unit 2.
These activities, subject to the limitations in this safety l
evaluation, fall within the scope of activities previously considered in PEIS Supplement 2 and the staff's environmental assessment.
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, k We have concluded, based on the considerations discussed above that 1 there I
is reasonable assurance that the health and safety of the publIc will(no)t be.
l endangered by operation in the proposed manner, and (2) such activities will be conducted in compliance with the Comission's regulations, and (3) the issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public.
6.0 REFERENCES
a.
Programmatic Environmental Impact Statement related to decontamination and disposal of radioactive wastes resulting from March 28, 1979 accident at Three Mile Island Nuclear Station, Unit 2, Supplement 2 (NUREG 0683, supplement 2), June 1987 b.
GPUN letter 4410-88-L-0012/0335P dated February 16, 1988, from F. R.
Standerfer to NRC with attached Accident Generated Water Disposal System Description c.
GPUN letter 4410-88-L-0168/0428P, dated October 7, 1988 from M. B. Roche to NRC with attached Processed Water Disposal System Technical Evaluation Report (TER).
d.
GPUN letter 4A10-89-L-0038/0455P dated April 17,1989 from M. B.
Rocne to NRC re Processed Water Disposal System TER e.
GPUN letter 4410-89-L-0067/0469P dated June 7, 1989 from M. B. Roche to NRC re Processed Water Disposal System TER f.
NRC letter dated February 16, 1989 from J. F. Stolz to M. B. Roche, GPUN, re Processed Water Disposal System TER g.
NRC letter dated May 31, 1989 from M. B. Masnik to M. B. Roche, GPUN, re Processed Water Disposal System h.
GPUN memorandum with attachments, dated February, 16, 1989 from J. A.
Thomas to D. R. Buchannan re Licon Aquavap Testing Program Principal Contributors: Lee H. Thonus, Linda F. Munson Dated: September 11, 1989
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