ML19323B543
| ML19323B543 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 04/25/1980 |
| From: | NRC COMMISSION (OCM) |
| To: | |
| Shared Package | |
| ML19323B542 | List: |
| References | |
| NUDOCS 8005130531 | |
| Download: ML19323B543 (22) | |
Text
0513060k 8 0 CHARTS USED FOR PRESENIATION TO CONGRESSMAN ALLEN F. ERTEL, NRC COMMISSIONER VICTOR GILINSrf AND STAFF APRIL 25, 1980
~
Based on our experience, a review of existing documents and various discussions with those we consider to be experts in the field of dose assessment we would technologically conclude with full knowledge of the altenatives :
The best approach to the 85 Kr problem would be the e
prolonged, controlled venting of the containment atmosphere to the environment.
Venting should be accomplished without detectable e
increase of our natural background as monitored by trained i.ndependent groups.
e For continued safety at. the TMI site early entry into containment is necessary for equipment main-tenance and radiation surveys.
~
Since March 29, 1979, the Oak Ridge National Laboratory has been involved in the T MI situation.....
Providing emergency on-site assistance in contaminated air and water effluent control.
Providing consultation to the Kenemy Commission
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In post-accident cleanup e
In understanding the chronology of events In technical guidance in a series of "what-if" studies In providing dose assessment information e
In other technological areas not related to this e
discussion
.Providing analytical enemistry service where unique capabilities are mandated.
Providing assistance to the TMI Technical Advisory Group.
Providing continuous assistance in the area of high-level e
-wa-ter - f lowtheet - d evelop ment and verification.
Providing
" trouble shooting" service to on-going cleanup operations as required.
l Providing input to NRC in understanding the in-depth e
technical sit u a t i,o n on water and waste treatment.
l 1
I i
e OBJECTIVES OF EFFORTS DURING WEEK OF APRIL 21,1980 IN RESPONSE TO REQUESTS MADE BY CONGRESSMAN ERTEL DURING HIS VISIT TO OAK RIDGE ON APRIL 19,1980:
e MAKE CALCULATIONS SHOWING TRADE-OFFS / OPTIONS AMONG DECONTAMINA-TION FACTORS, FLOW RATES, PROCESSING TIMES, ETC.
e EVALUATE APPLICABILITY OF PILOT PLANT EQUIPMENT FOR TMI-2 SYSTEM e
IDENTIFY PRIMARY ISSUES, PROBLEMS, ETC., IN IMPLEMENTING A SELECTIVE ABSORPTION SYSTEM UP TO TEN TIMES THE PILOT PLANT SIZE msmo
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E KRYPTON PROCESSING TIMES APPROXIMATE WEEKS TO ACHIEVE REDUCTION AT INDICATED FLOW RATE
% REMOVAL 15 scfm 50 scfm 150 scfm 90 33 10 3
99 66 20 6
99.9 99 30 9
4 1
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SCHEMATIC OF THE SELECTIVE ABSORPTION PROCESS 9
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R-12 MOLECULAR CONDENSER SIEVE LJ V
OPTIONAL RECY E MAKEUP 4
l OPTIONAL PRODUCT
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l GAS VENT COMBINATION COMPRESSOR
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l COLD l
TRAP Q
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REACTOR 2
BUILDING GAS RECYCLE Kr PRODUCT MOLE ULAR STORAGE llEPA SIEVE
'7 FILTER SOLVENT COOLER V
REVERSING GAS N
HEAT cAs COOLER
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l ik EXCHANGER {
COMPRESSOR 4A MOLECULAR SIEVE WO SOLVENT SOLVENT STORAGE PUMP 4/25/00 k
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l SELECTIVE ABSORPTION PROCESS BLOCK DIAGRAM a
i VENT GAS TREATMENT SUBSYSTEM J L REACTOR FEED Kr PRODUCT PRODUCT
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PREPARATION SEPARATION TREATMENT STORAGE BUILDING SUBSYSTEM SUBSYSTEM SUBSYSTEM SUBSYSTEM J L i f SOLVENT GAS MAKEUP TREATMENT SUBSYSTEM SUBSYSTEM UTILITIES SUBSYSTEM me, f65)
SUBSYSTEM DESCRIPTION SUBSYSTEM:
FEED PREPARATION PRIMARY FUNCTION:
FILTER, DRY, COMPRESS, COOL, AND METER FEED GAS MAJOR EQUIPMENT HEPA FILTERS REVERSING HEAT EXCHANGERS GAS COMPRESSOR GAS HEAT EXCHANGER / REFRIGERATION SYSTEM MOLECULAR SIEVE BEDS WATER STORAGE TANKS OPERATING REQUIREMENTS:
GAS FLOW PICKED UP AT SUBATMOSPHERIC PRESSURE, DISCHARGED AT 150 PSIA, DRIED TO A DEW POINT OF
- 900F (MEASURED AT 1 ATMOSPHERE), AND COOLED TO - 300F CONSIDERATIONS:
TRITIATED WATER MUST BE COLLECTED FOR STORAGE AND SUBSEQUENT PROCESSING; MOLECULAR SIEVES PROBABLY MUST BE DISPOSED OF AS CONTAMINATED WASTE AFTER USE msina
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SUBSYSTEM DESCRIPTION E
5 SUBSYSTEM:
Kr SEPARATION COLUMN PRIMARY FUNCTION:
REMOVE Kr FROM THE FEED GAS, CONCENTRATE Kr, AND REGENERATE SOLVENT FOR RECYCLE MAJOR EQUIPMENT:
COMBINATION COLUMN Wl'TH INTEGRAL REBOILER OPERATING REQUIREMENTS:
Kr DECONTAMINATION FACTOR OF 100, Kr CONCENTRATION I
FACTOR OF 2 x 104 CONSIDERATIONS:
ALSO REMOVES Xe AND CO2 l
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SUBSYSTEM DESCRIPTION l
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SUBSYSTEM:
VENT GAS TREATMENT PRIMARY FUNCTION:
REMOVE R-12 VAPOR FROM PROCESS OFF-GAS TO REDUCE SOLVENT LOSS AND PREVENT VA?OR FROM BEING RE-CYCLED BACK TO THE REACTOR BUILDING (IF RECYCLE IS EMPLOYED)
MAJOR EQUIPMENT:
CONDENSER / REFRIGERATION SYSTEM MOLECULAR SIEVE BED OPERATING REQUIREMENTS:
R-12 CONTENT IN THE EFFLUENT GAS LESS THAN 1 PPM CONSIDERATIONS:
SMALL AMOUNTS OF R-12 VAPOR MIGHT BE RECYCLED TO THE REACTOR BUILDING IN RECYCLE CASE 4
4/25/80 O
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SUBSYSTEM DESCRIPTION g
SUBSYSTEM:
SOLVENT TREATMENT PRIMARY FUNCTION:
PURIFY, PUMP, COOL, AND F ' ITER SOLVENT FLOW TO THE ABSORBER MAJOR EQUIPMENT:
MOLECULAR SIEVE BED SOLVENT STORAGE TANK SOLVENT PUMP SOLVENT COOLER / REFRIGERATION SYSTEM OPERATING REQUIREMENTS:
SOLVENT FLOW AT CONDITIONS REQUIRED BY THE OPERATION OF THE ABSORBER CONSIDERATIONS:
DISPOSAL OF MOLECULAR SIEVES AS CONTAMINATED WASTE e s/so 1
4 i
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SUBSYSTEM DcSCRIPTION 3
SUBSYSTEM:
PRODUCT TREATMENT PRIMARY FUNCTION:
REMOVE SOLVENT VAPOR, Xe, AND CO FROM 2
PRODUCT Kr MAJOR EQUIPMENT:
MOLECULAR SIEVE BED COLD TRAP / REFRIGERATION SYSTEM OPERATING REQUIREMENTS:
R-12 CONCENTRATIO'N IN THE PRODUCT Kr LESS THAN 1 PPM, Xe AND CO2 LESS THAN 0.1 MOLE PERCENT CONSIDERATIONS:
DISPOSAL OF THE Xe AND CO, REGENE: RATION 4
2 OF MOLECULAR SIEVE BED INTO SYSTEM AS PRECAUTION l
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SUBSYSTEM DESCRIPTION i
SUBSYSTEM:
PRODUCT STOR AGE PRIMARY FUNCTION:
STORAGE OF CONCENTRATED KRYPTON MAJOR EQUlPMENT:
GAS COMPRESSOR STORAGE CYLINDERS STORAGE CASKS OPERATING REQUIREMENTS:
DOUBLE CONTAINMENT, RADIATION SHIELDING, AND COOLING OF PRODUCT AS REQUIRED FOR STORAGE CONSIDERATIONS:
LONG-TERM PROTECTION i
9 I
SUBSYSTEM DESCRIPTION I
5 SUBSYSTEM:
GAS MAKEUP j
PRIMARY FUNCTION:
REGULATE REACTOR BUILDING PRESSURE MAJOR EQUIPMENT:
NITROGEN MAKEUP SYSTEM FOR VAPORIZATION OF LIQUID NITROGEN AND CONTROL SYSTEM TO REGULA~i d MAKEUP FLOW: ABSORBER OFF-GAS RECYCLE PIPING PROVISIONS CONSIDERATIONS:
NITROGEN MAKEUP PREFERRED OVER USE OF ATMOSPHERIC AIR TO AVOID UNNECESSARY CO2 BURDEN ON ABSORBER PROCESS AND PRODUCT TREATMENT OFF-GAS RECYCLE WOULD PERPETRATE OLOSED LOOP CONTAINMENT DURING DURATION OF ABSORBER PROCESSING OFF-GAS RECYCLE MIGHT INTRODUCE A SMALL QUANTITY OF R-12 VAPOR TO THE REACTOR BUILD-ING IF VENT GAS TREATMENT SYSTEM MALFUNCTIONS ans/m
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IMPLICATIONS OF CURRENT GAS INVENTORIES IN TMI-2 3
COMPONENT VOLUME, FT CONCENTRATION, PPM Kr (TOTAL)
N 16 8
Xe N110 N 55 CO 660 330 2
NOTE: BASED ON ESTIMATED CONCENTRATIONS; MEASUREMENTS DESIRED e
ABSORPTION PROCESS OFF-GAS RECYCLE TO CONTAINMENT OR NITROGEN MAKEUP FOR ONCE-THROUGH SYSTEM AVOIDS ADDITIONAL CO AND Kr 2
BURDEN ON PRODUCT TREATMENT AND PRODUCT COLLECTION SUBSYSTEMS IMPOSED BY FRESH AIR MAKEUP e. SUBSTANTIAL REDUCTION OF EXISTING CO2 AND Xe VIA PRODUCT i
TREATMENT SUBSYSTEM IS DESIRABLE TO REDUCE VOLUME STORED 4/25/80 4
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E SUBSYSTEM DESCRIPTION SUBSYSTEM:
UTILITIES PRIMARY FUNCTION:
DROVIDE UTILITIES REQUIRED BY THE ABSORBER SYSTEM MAJOR EQUIPMENT:
ELECTRICITY; PUMP POWER, LIGHTING, HEATING:
COOLING WATER FOR REFRIGERATION SYSTEMS, SUPPLY AND RETURN CONNECTIONS; COMPRESSED AIR FOR PNEUMATIC INSTRUMENTATION; NITROGEN FOR SIEVE REGENERATION OPERATING CONDITIONS:
SPECIFIC' UTILITY DEMANDS WOULD RESULT FROM TOTAL SYSTEM SIZING AND DESIGN CONSIDERATIONS:
ASSUME THAT SPECIFIED UTILITIES WOULD BE AVAILABLE TO THE BUILDING HOUSING THE ABSORBER SYSTEM WHEN THE COMPONENTS ARE SET UP ON SITE l
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PILOT PLANT HARDWARE APPLICABILITY AVAILABILITY i
MAJOR AT 15 SCFM SIZE
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l SUBSYSTEM EQUIPMENT ITEMS FROM PILOT PLANT l
FEED PREPARATION HEPA FILTERS NO REVERSING HEAT EXCHANGER NO 3
GAS COMPRESSOR X
GAS HEAT EXCHANGER /REFRIG.
X MOLECULAR SIEVE BEDS NO Kr SEPARATION COMBINATION COLUMN WITH X
INTEGRAL REOILER VENT GAS TREATMENT CONDENSER / REFRIGERATION NO MOLECULAR SIEVE BED NO SOLVENT TREATMENT MOLECULAR SIEVE BED X
SOLVENT STORAGE TANK X
SOLVENT PUMP X
SOLVENT COOLER /REFRIGER ATION X
PRODUCT TREATM ENT MOLECULAR SIEVE BED X
COLD TRAP / REFRIGERATION X
PRODUCT STORAGE GAS COMPRESSOR NO STORAGE CYLINDERS NO STORAGE CASKS NO GAS MAKEUP SUBSYSTEM ALL NO UTILITIES ALL NO INSTRUMENTATION X (PARTI AL)*
- SOME INSTRUMENTATION ALSO APPLICABLE TO LARGER SYSTEM.
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SOME CONCERNS ABOUT RELOCATION OF Tile OllGDP SELECTIVE ABSORPTION PILOT
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PLANT TO TMI-2 AND INCORPORATION OF THE TEST UNIT AS PART OF A KRYPTON REMOVAL SYSTEM THERE:
ONLY HALF OF THE MAJOR EQUIPMENT ITEMS NECESSARY FOR Tile TMI-2 APPLICATION ARE USED IN AND AVAILABLE FROM THE PILOT PLANT EXISTING REFRIGERATION SYSTEMS ARE OLD e
OTHER ITEMS WHICH MIGHT BE AVAILABLE DO NOT APPEAR TO BE ON THE CRITICAL PATH. THEREFORE, SCHEDULE ADVANTAGES ARE NOT APPARENT THE PILOT PLANT FLOW RATE (15 SCFM) IS LOWER THAN WHAT WE CONSIDER TO BE A PRACTICAL MINIMUM (ABOUT 50 SCFM) FOR THIS APPLICATI.ON RELOCATION COST SAVINGS (IF ANY) VERSUS NEW FABRICATION WOULD BE MODEST
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SYSTEM NOT DESIGNED FOR RELOCATION 1
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PROBLEMS, ISSUES, CONCERNS ASSOCIATED WITH USE OF A SELECTIVE ABSORPTION PROCESS SYSTEM l'
(~100i 50 SCFM) FOR REDUCING Kr RELEASE AT TMl-2 a
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CRITERIA FOR Kr-85 STORAGE 5
BASIC OBJECTIVES AND CRITERIA WHICH GOVERN PROJECT SCOPE, SCHEDULE, COST, 9
AND PROGRAMMATIC IMPACT (IS SECTION 8 ASME ADEQUATE 7, WHAT IS TARGET DF?,
WHAT ARE REGULATORY REQUIREMENTS?, ETC.)
e RESPONSIBILITIES FOR PROJECT PHASES: TECHNOLOGY SPECIFICATION, DESIGN, APPROVAL, PROCUREMENT, CONSTRUCTION, OPERATION (DOE, NRC, AE'S, GPU/ MET.ED.)
AND INTERFACES AMONG PARTICIPANTS i
e POTENTIAL LONG LEAD HARDWARE ITEMS, SUCH AS:
e SEALED GAS COMPRESSORS 8 - 10 MONTHS e
HEPA FILTERS 10 - 12 MONTHS e
REFRIGERATION SYSTEM 8 MONTHS CONTROLLERS / INSTRUMENTATION 6 MONTHS e
Kr-85 CASK, CYLINDERS LONG ??
e BUILDING ISSUES (AVAILABILITY, ETC.)
e EXACT COMPOSITION OF REACTOR BUILDING ATMOSPHERE 4nszoo
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KEY ELEMENTS OF A " CRASH" PROGRAM EARLY CHECK WITH INDUSTRY TO DETERMINE COMPONENT AVAILABILITY (AND EVEN PLACE OPTIONS) PRIOR TO FREEZING ON DESIGN FLOW RATE NEGOTIATE ALL PROCUREMENTS AND CONTRACTS RATHER THAN BID e
USE ACCEPTED INDUSTRIAL STANDARDS AND PRACTICES FOR HAZARDOUS MATERIALS RATHER THAN NUCLEAR REACTOR COPES (EXCEPT FOR NUCLEAR STANDARDS FOR Kr STORAGE)
NO REGULATORY PROCESS DELAYS NO SPECIAL EFFORT TO MAKE SYSTEM MOBILE (1.E., NO EFFORT TO MAKE THE UNIT GENERALLY APPLICABLE TO OTHER SITUATIONS) i 4/75/80 9
l PREVIOUS UCC-ND ESTIMATES OF COSTS AND SCHEDULES FOR SELECTIVE ABSORPTION UNIT FOR TMl-2 0
l l
l CONSTRAINTS COST, $ MILLIONS SCHEDULE, YR LICENSABLE - NORMAL PROGRAM 15-20 4
LICENSABLE
' CRASH' PROGRAM 15-20 2
NOT LICENSABLE - NORMAL ?ROGRAM 10'i5 3-1/2 - 4 NOT LICENSABLE
' CRASH' PHOGRAM 10-15 1-1/2 - 2 BASIS: COMPLETE MOBILE UNIT,275 SCFM CAPACITY I
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imt April 21, 1980 017;u5 4843 Hon. John F. Ahearne Chairman Nuclear Regulatory Commission 1717 H Street, N.W.
Washington, D.C.
20555
Dear Chairman Ahearne:
Having had the opportunity to review the various cleanup cptions presented to the Nuclear Regulatcry Commission and having studied the reports on the Selective Absorbtion System prepared by Dr. Gerald pellack at the request cf Ccmmissicner Gilinsky, I felt the Selective Absorbtien System required more censideration.
On Saturday, April 19, NRC Commissioner Victer Gilinsky and I flew to the Oak Ridge Gaseous Diffusion plant, in Oak Ridge, Tennessee, to examine the pilot plant designed to remove Krypton-85 (Kr-85) from a contained atmosphere through the Selective Absorbtion process.
This process is described on pages 6-32 through 6-38 of the NRC EnYirenmental Assessment for Decontamination of the Three Mile Island Unit 2 Reacter Building Atmosohere (NUREG-0662).
Commissioner Gilinsky and I also had the opprtunity to discuss this process with the engineers who have designed and operated this pilot plant, and officials from Union Carbide which hss conducted the program under contract with the Depart.ent of Energy.
~
The Selective Absorbtion System has been werked on at the Oak Ridge Caseous Diffusien plant since 1967.
The system today is a third-generation proces. which has be3n operating successfully for one and one-half years.
Its flow rate is 15 cubic feet per minute.
With the obvious exception of venting, the Selective Abscrbtion process is the least expensive of the cptions presented in NUREG-0652 and could be placed in operation at TMI 2 in less time than the other options. According to the engineers at Oak Ridge, assuming the availability of materials and the necessary approvals, this system can be built and tested in about three months. This contrasts with the time requirement discussed in NUREG-0662.
Because I believe that the Nuclear Begulatery Commission, and all other active parties, are moving toward approving the yenting of f
the radioactive gases in the damaged reactor, I am concerned that adequate consideratien has not been given to the Selective Abscrbtien System.
The Selective Absorbtien System has already been preven to be effective, and it can be put into place quickly.
passing the gases in TMI Unit 2 through the system only ence would reduce the Kr-85 in containment by a factor cf 100 to 1000 times. Scaling the pilot plant um frem a 15 cubic feet / minute flew rate to a rate of v 4c.. no tuo toJPrepare Reply for Signature of Chairman..Date due' Ccc: Ma~v 1 Cpys0:
Chm, RF, Oli u.. 80-0794-THIS STATicNCRY PRINTCo cN PAPCR MAOC WITM MCCycLCD Figems
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Page 2 Hon. John F. Ahearne April 21, 1980 200 cubic feet / minute does not represent any significant probleEs.
The system is,not a ecmplex one and its components are all "off-the-shelf" items which should be readily available.
We must remember in assessing this cptien that:
the Kr-85 is already in the reacter at TMI; unless we implement the Selective Absorbtion System, the Kr-85 will be vented into the atmosphere; the worst that could happen with the Selective Absorbt3cn System is a failure requiring venting (an option which will be other, wise approved).
In additicn, it is not necessary to require that the Selective Abscrbtion System be built to nuclear cede ccnstruction standards.
This will only delay the process and, because of the small volume of gases in the system at any one time, even a total failure would not result in any major detrimental release.
I believe that venting is unacceptable for a number of reascns.
The Selective Absorbtion System appears to be a viable alternative. The longer we spend debating the various optiens, the mere we force ourselves into a situatica where venting is the only alternative because of time constraints.
In accordance with our converation, it is my understanding that a detailed analysis on this system will be prepared by Oak Ridge by this Friday.
This detailed analysis should confirm the initial conclusien that this sytem should be utili=ed.
I am anxious to work with you in moving ferward with this p?ocess and will do everything in my power to expedite its installation and operation.
b Sincerely
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l QAAlen E. Ertel MEIGER OF CONGRESS AEE/bh cc:
Hon. Victor Gilinsky, Commissicner, Nuclear Regulatory Commission Hon. Peter Bradford, Commissioner, Nuclear Regulatory Commissien bon. Jeseph M. HendriE, Commissioner, Nuclear Regulatory Commissien Hen. Richard T. Kennedy, Commissioner, Nuclear Regulatory Commission Hen. Charles Duncan, Secretary, Department cf Energy Mr. George W. Cunningham, Assistant Secretary for Nuclear Energy, DOE M.. Jack H. Watsen, Jr., Assistant to the President for Inter-governmental Affairs Hen.' Richard Thernburgh, Geverner, Ccmmenwealth cf Pennsylvania Mr. Herman Cieckamp, President, General Public Utilities Mr. Robert Arnold, President, Metrepelitan Edisen Mr. Walter Vannoy, President, Eabecek and Wilecx Mr. R. J. Hart, Union Carbide
I MICHIGAN STATE UNIVERSITY contcs of NATURAL SC;DCE
- OtPARTMbT OF PHY$1CS EAST LANSING
- 46C4 i
March 31,1980 j
The Honorable Victor Gilinsky Commissioner US Nuclear Regulatory Commission 1717 H Street, NW Washington, DC 20555
Dear Dr. Gilinsky:
Here is my report on the suitability cf the Selective Absorption Process System for removing Krypton-85 from the atmosphere of the reactor tuilcing of Unit 2 at Three Mile Island.
This is a follow-up to my previous report, of March 24, to you.
In order to prepare this and to learn more about the system at first-hand I visited and talked with the group which develcped it at the Oak Ridge Gaseous Diffusion Plant. While I was there I examined as well as I could the pilot-plant scale system which they've constructed.
I also read and studied some of their reports.
I asked them many questions and I made the questions as probing as I could; I think that I have an accurate picture of their system and its prcperties.
My main cenclusion is that the Selective Absorption Process System could be used to remove the Kr-85 from TMI-2 and would probably do an excel-lent job.
My visit to the f'acility confirmed my opinion that Selective Absorption is the best choice of the five alternative methods for Kr-55 decontamination discussed in the NRC Staff Report's Environmental Assessment.
The Cryogenic Process System is the second best choice, in my opinien.
I do not have any first-hand experience with the Cryogenic Process System so this is still scmewhat tentative.
The Reactor Building Purge is my third choice.
In view of what I learned about the Selective Absorption l
2 System, I think that there is probably no need to actively consider further the Charcoal Adsorption System or the Gas Compression System.
These were, respectively, the fourth and fifth choices in my' report of March 24.
I see now that they would have all of the disadvantages but none of the advantases of the Selective Absorption System.
The only disadvantage of the Selective Absorption System compared to any of the other four alternatives is that it would take longer and cost more th'an. the Reactor Building Purge.
The advantage of Selective Absorption over purging is that it is a zero-release system and so would have minimal.
public and environmental effects.
I understand that during the time it' would take to at up a decontamination system, emergencies could arise which would require that extensive work be done in the reactor atmasphere.
I haven't included this problem since I don't know its details.
In the main body of this report I shall discuss several of the scien-tific, engineering, anc other aspects of the Selective Absorption System which bear en its use at TMI-2.
I have kept the discussions brief but I am prepared to provide you with quantitative details of any of the points.
A.
How the Selective Absorotion System removes Kr-85 from a contaminated atmosobere.
Krypton is preferentially soluble in the common refrigerant Freon (a fluorocarbon, CCl F ).
The 3 dea is to dissolve Kr-85 in a counterflowing 22 stream of liquid Freon.
The contaminated reactor atmosphere is fed into the absorption section of the system where the refrigerant is cold and absorbs Kr-85. Absorbed gas is carried by the stream to the stripping section of the system where the refrigerant is heated and therefore releases 1
the Kr-85 and other volatile soluble contaminants into a collecting system.
The Kr-85 ultimately is concentrated in standard-sized gas cylinders.
3 B.
What has been done with the system so far.
The group at the Oak Ridge Gaseous Diffusion plant (ORGDp) has.been working on the Selective Absorption System since about 19o7.
From 1974-1978 they operated a secon'd generation working, pilot-plant system (a three-stage system with separate columns for absorption, intermedi7te stripping and final stripping).
They made extensive tests on studying, varying, and optimi:ing the parameters of this system in order to improve it and they have ccustructed a third generation pilot-plant system..This system is an improved, single-stage, system and has been cperating for 1 1/2 years..
It is operated regularly now for 4 days a week.
It was working when I visited OR3Dp and I examined it.
The principle motivation of the ORGDP group in developing this system was for use to treat and decontaminate the off gas from nuclear fuel reproc-essing plants.
However, the system can also be straightforsardly adapted and used for cleaning radioactive atmospheres from a reactor accident such as the one at TMI-2.
The relevant divisions at ORGDp have considered the problem of the TMI-2 reactor atmosphere decontamination and they have written a preliminary proposal on how they would go about it.
I read the proposal and the scientific and engineering parts seem to me to be solid.
There is a unique aspect of this Selective Absorption System which
~
strengthens it.
There are three people at ORGDp who have worked on the systim extensively: Drs. J. R. Merriman, M. J. Stephenson, and B. E.
Kanak.
A large fracti_on of their scientific careers has been involved with the system and it has been the subject of doctorai and master's degree. theses.
This means that the group has a firm, first principles, understanding of the system. I think that is an invaluable advantage to have in using the system and scaling it up.
4 i
C.
What are the scientific and encineerino considerations in usinc this system for the cleanuo at TMI-27 The Selective Absorption System that is proposed for use at TMI-2 would process about 250 Standa-d Cubic Feet per Minute (SCFM) of reactor atmosphere.
It would achieve 90% removal of Kr-85 on a single pass of atmosphere through the column and provisions could be made for recycling.
Such a system would clean up the reactor atmosphere in about 60-70 days, once it was functioning in place.
The scale of the system that would have to be built for TMI-2 is naturally larger than the pilot-plant scale.
For example:
The present' pilot plant uses abscrptien colurn tubes that are 3" in diameter, whereas the TMI system would use tubes about 20" in diameter.
The pilot plant has a throughput of 15 SCFM compared to 250 SCFM for the TMI system, as men-tiened above.
In my judgment this scale-up would cause no problems.
Because the system has built-in elasticity of design, it will probably be easy to optimize and, if necessary, trouble-shoot.
For example:
(a)
One can' vary the pressure and temperature, presently planned at 125 psig and -30*F, since these regicns are convenient t: work in.
(b) One can vary the gas throughput rate as well as the solvent flow rate.
(c) In the pilot-plant scale, separations in a singl'e pass of 99.9% for Kr-85 have been r
achieved but for application at TMI only 90% is required in a single pass.
(d) One can vary the number of cylinders and the pressure inside them for collection and final s.torage of the Kr-85; presently this is planned at about 5 standard cylinders at 500 psia.
There is one important point which, in my opinion, requires further ex;eriment now.
That point is the different Kr concentration scale that we encounter at TMI-2 compared to the pilot plant.
The pilot-plant system
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5 has been tested at Kr concentrations from 0.1 ppm to 880 ppm.
However my calculations show that at TMI-2 the Kr-85 concentr ation new is 0.7 ppm and it will probably'be necessary to reduce the totai Kr levels to well below 0.1 ppm.
It is important to test the pilot-plant system at these icwer levels to be sure that good separation factors can be achieved.
I am fairly ccnfident that this will not be a serious problem but it must be tested.
D.
What is the c0st and how lanc would it take to set us a Selective Abscrotion System at TMI-2?
The pecple invcived give ccst estir.ates fer the Selective Absorption cleanup cf Kr-85 ranging frcm $4-20 million and estimated times frca 11/2 to 4 years. The higher cost and longer time estimates are due to concerns they have about special expensive hardware, materials and techniques required for the system to be built and operated rigorously to nucicar code con-struction standards. The estimates also reflect their concerns about potential delays due to legal and political prcblecs.
Finally there is feeling that there may be unfortseen delays and expenses associated with interactions between DOE and General Public Utilities and NRC.
In this connection it's natural to ask whether in the interests of economy and speed in the cleanup:
Is it possible to smooth these interactions?
Is it advisable to modify the construction standards?
'In contrast it should be emphasized that scientific and engineering considerations alone a.re censistent, in my opinion, with a time of 1 1/2 years and a relatively low cost estimate.
The Selective Absorption System is less cc plicated than current autorebile emissions systems,its principles of operation are simpler and it is easier to fix.
6 E.
Other advantaces associated with develcoinc the Selective Absorotion System for use at TMI-2.
(1) The sysi:em could be mobile.
One design proposed by ORGDP would fit on five trailers so that after use at TMI the system could be used at any future reactor accidents.
(2) Once the system is scaled up for use at TMI, it would be closer to the further scale up necessary for decontamination of off gases from operation. of reprocessing plants.
That is a problem that we shall soon have to solve and this is probably a good approach.
(3) The present system traps tritium (99.99% removal in a single pass).
Since there is a lot of tritium in the reactor building at TMI (3.ox10-5 uCi/cm ), one could use the same selective absorption system for 3
the tritium cleanup.
(4) Once the system were developed for use at TMI and should it prove as efficacious as anticipated in the cleanup, the portable system might be marketable worldwide (DGE has a patent on the process).
(5) Finally, and somewhat conjectural:
The system collects and con-centrates Xe as well as Kr. This opens up the possibility that a Selective Absorption System could be used to decontaminate the off gases associated with normal operation of nuclear re' actors. One might then be able to achieve essentially zero radioactive gas release from reactor operation.
I believe this would lead to better public acceptability of nuclear power.
Report submitted by, Y, $0bt.
Gerald L. Pollack Professor of Physics ds e
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March 24, 1980 a
y a
F The Honorable Victor Gilinsky f
Commissioner US Nuclear Regulatory Commission 1717 H Street, N.W.
Washington, DC 20555
Dear Dr. Gilinsky:
Here is my report on the alternative methods for removing Krypton-85 fremtheatmosphereofthereactorbuildingcfUnit2atThreeidileIsland.
In preparing this report, I have studied the NRC Envirer. mental Assessment as well as other relevant scientific and engineering literature.
It's a hard problem and my conclusions are still tentative.
I should like to get first-hand experience with the alternatives.
Then I will be able to recon-sider and firm up the conclusions.
The first part of this report is an introduction to the prcblem.
The second part is a brief discussion of eacn of the five alternatives; they are discussed in order frcm most preferred, in my opinion, to least preferred.
I.
Introduction The problem we need to solve is how to decontaminate the atmosphere of the reactor building at TMI-2.
The main contaminant is Kr-85, a radioactive inert gas.
The resulting radioactivity concentration now is high,1.0 pC/cm.
The atmosphere must be cleared so that there can be free and safe access to the building to get on with the rest of the cleanup., We would like the i
decontaminatien to be safe, with minimal exposures to the public and to workers, and to be as inexpensive and cuick as ;ossible within these c:n-straints.
2 The amount of Kr-85 that is in the reactor building is 57,000 Ci.
The particular difficulties involved with getting rid of Kr-85 are,:
(a)
It has a long half-life (10.76 years) so that it decays slowly (b) It is an inert gas so there are no easy chemical means for removing it, and 6
3 (c) It is mixed in with the 2x10 ft of air in the reactor building.
Although the radioactivity due to the Kr-85 is large, the amount of gas is fortunately small.
The actual amount of gas is only 1.7 moles, which at standard temperature and pressure (STP) conditions would occupy 3
only 38 liters er 1.4 ft.
Thus if the Kr-85 gas could be efficiently separated out it wculd all fit easily into cne standard-sized gas cylinder at low pressure.
As it is there are alternatives available which will con-tain the Kr-85 in a few gas cylinders at scmewhat higher pressures.
In my judgment the most naturai solution to the problem is to the advantage of this; I recomend ;
eth:c that in the end concentrates the gas in cylinders e..id, as far as possible, has ::ero release to the atrosphere.
Fortunately two of the available alternatives do that, the Selective Absorption System and the Cryogenic ? recessing System.
Will long-term st: race cf Kr-85 be safe?
If the Kr-85 gas is to be concentrated and stcred we must provide for long-term safe storage.
I believe that this is not difficult to do when one considers the nature of the emitted radioactivity.
For Kr-85, 99.6% cf the nuclear decays result in emission of a beta ray of energy.690 kev.
Since this radiation consists of charged particles it will be stopped by the walls of any containing vessel.
The other 0.2% cf the nuclear decays emit mainly gama rays of energy 514 kev.
I have calculated that the intensity of this radiation is 6
reduced by a factor cf 10 by lead shielding 3.25" thick or by 27" of cencrate.
Thus the st: race micht simply c:nsist of a few stainless-steel
3 cylinders of gas contained in a few bookcase-sized lead and concrete con-If Outside these containers the radiation will be undetectable.
tainers.
the storage is carried out for 100 years (i.e. 9.3 half-lives) the t6tal radioactivity will be down to 91 Ci.
I believe that good quality stainless-steel cylinders and valves will last this long without significant deterio-ration.
Alternative Methods for Decontaminatina the Reactor Buildino II.
I have tentatively concluded that the best method of those available Selective Absorption Process System and that the second best method is the The remaining r.ethods are, in my opinion, is the Cryogenic Process System.
The Reactor Building all considerably less desirable than these first uo.
Purge is, on balance, my third choice, the Charcoal Adsorption System is fourth, and the Gas Compression System is fifth.
Each of these systems is discussed briefly below.
A. Selective Absorotion Process System _
The operating principle of this system is that Freon (CF C1 ) absorbs 2 2 The idea is to run the reactor building atmcsphere through a noble gases.
column of liquid Freon.
The Kr-85 will be removed from the air, the decon-is returned to the reactor building, and the Kr-85 may be taminated air isolated and concentrated.
In my opinion this system is probably the best alternative for these (1) The end product is radioactive Kr-85 in a few standard-sized reasons:
I believe that these can be relatively easily handled and
gas cylinders.
stor'ed safely as previously described.
(2) It is a zero-release system, i.e. in principle no Kr-85 will get out to the atmos;ihere and thus there.
will be minimal offsite doses.
(3) The system has already been extensively The Oak developed to a pilot-plant scale at Oak Ridge National Laboratory.
4 Ridge-Union Carbide people are apparently confident that the system can be satisfactorily scaled up.
(4) Except for purging, this system is the least expensive alternative (54-10 million) and the fastest to bring into operation (about 1 1/2 years).
(5) The pressure and temperature at which the system operates are easily handled.
My main hesitation with recomending this system is that I have no first-hand experience with it.
I would like to study it more closely and learn more about the details of its operation before taking a final judgment.
B. Cryocenic Process System The operating principle of this system is that Kr-E5 may be separated frem the other gases in the reactor building atmosphere by preferential condensation.
The idea is that the boiling-point temperature (120*K) and the triple-point temperature (116*K) of Kr are higher than those of the nitrogen and oxygen in air. Thus if the atmosphere is exposed to a suit-ably cooled surface, the Kr-85 will be preferentially deposited by con-densation.
This allows for concentration of the radioactive gas.
This system is probably the second best alternative.
These are some of the considerations:
(1) The end product is isolated radioactive Kr-85 which could, for example, be contained in 57 gas cylinders each with 3
10 Ci.
These could be safely handled and stored.
(2) Unfortunately, this system is rather complex and somewhat more expensive ($10-15 million) than the Selective Absorption System.
(3) Offsetting this is the advantage that there is an available system, which is about to be scrapped, which could be purchased and used at TMI.
I take it that the system is functional and that its characteristics are well-known to the present owners.
(4) The system is not quite a zero-release system; about 0.1% of the Kr-85 would be released.
1
)
5 C. Reactor Buildine Purce The operating principle of this system is that the Kr-25 can be
~
released through the plant vent stack over an extended period.
For the
-suggested 60-day release period the average emission rate is 0.66 Ci/ min.
This is the least expensive and quickest of the alternatives but it has the greatest public dose of radioactivity. One can calculate from the usual meteorological considerations that the offsite public dose would be within design objectives.
The idea behind t~ is system is the antithesis of the previous alter-n natives (A and B).
Those previc 3 eiternatives ended up with maximum con-centrations of isolated Kr-85 with minimal release of radioactivity.
This system produces maximum dilution of the Kr-85 by releasing all of it to the atmosphere.
In ray opinion this alternative is substantially less desirable than the Selective Absorption or Cryogenic Process Systems.
Some of the con ~
siderations are these:
(1) Meteorological conditiens are notoriously hard to predict and values of the meteorological dispersion parameter (X/Q) are notoriously uncertain. Once the Kr-E5 gocs out of the stack it is out of control.
(2) As long as the Kr-S5 is contained, the beta rays it emits will be abs. orbed by the container walls.
It is only when the Kr-85 is in the open air that these beta rays can give doses to skin, lung epithelia, etc.
(3) In my opinion some of the claimed advantages are largely semantic.
Thus it is claimed (page 6-7 of NUREG-0662) that purging
" eliminates the need for long term surveillance of Kr-85."
I submit that the need for surveillance is still there after purging but our ability to carry it out is unfortunately eliminated.
(4) Finally, I think that con-siderations of public sentiment and psychological stress point strongly against this alternati:a.
r 6
D. Charcoal Adsorption System, and E. Gas Comoression System These systems can be discussed together since they share some connon
' features.
The systems both remove the Kr-85 from the reactor building atmosphere and the resultant radioactive gas is stored in large volume containers.
Both methods are expensive and would require construction of large permanent structures on site, in which the Kr-85 is stored in dilute form.
In the Charcoal Adsorption System the Kr-85 is ultimately adsorbed en charcoal and stored in frcm 150 (refrigerated adsorber) to 450 (ambient adsorber) tanks each 60 feet high.
In the Gas C:mpressicn System the Kr-85 is ultimately stored under pressure mixed in with 23,000,000 ft3(STP)of air. 'Since tne Kr-85 alone would occupy only 1.4 ft this seems like a needlessly inefficient procedure. The storage procedure for this alternative involves 28 miles of pipe of 36" outside diameter.
In my opinion the problems of maintaining the large Kr-85 storage systems for long term, and free of leaks,as required by both of these alternatives are very serious.
Report submitted by, k
Gerald L. Pollack Professor of Physics ds S
.