ML19322D796
| ML19322D796 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 02/04/1980 |
| From: | Ahearne J NRC COMMISSION (OCM) |
| To: | Heinz J SENATE |
| Shared Package | |
| ML19322D797 | List: |
| References | |
| NUDOCS 8002290151 | |
| Download: ML19322D796 (9) | |
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UNITED STATES NUCLEAR REGULATORY COMMISSION n
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WASHINGTON, C. C. 20566 5
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Come February 4,1980 c4(
CHAIRMAN h
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The Honorable John Heinz United States Senate IE Washington,0. C.
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Dear Senator Heinz:
'This is in response to your November 26, 1979 letter to Dr.' Hendrie concerning the decontamination.and disposal of Three Mile Island's radioactive waste.
The release or venting to the atmosphere of krypton contained in 'the THI-2 f
reactor building is currently not permitted. On November 13, 1979, the licensee transmitted to the NRC an analysis of the safety and environmental consequences of the removal of radioactive krypton from the reactor building.
In this analysis, the lic.ensee considered various alternatives and concluded that the venting operation could be 'done with no significant hazard to sice personnel or the general public. On this basis, the licensee proposed atmospheric venting as the means for removing contaminated gases from the reactor building. ~The NRC is currently preparing an Environmental Assessment of the krypton disposal alternatives and, upon completion of this Assessment, i
will request comments from the public for consideration. The options con-sidered by tne licensee, as well as art additional option being considered by
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the NRC staff, are described in Enclosure 1.
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This Environmental Assessment may be used as part of a near-term decision
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regarding the disposition of the krypton; in any event, it will be fully incorporated into the programatic environmental impact statement which is being prepared to include the total cleanup and decontamination operation.
As for the di.sposal of the water which has been decontaminated by the EPICOR-I h
II system, releasing such water into the Susquehanna River is also prohibited at this time. Although the licensee is currently considering a number of options for.the disposal of the water, described in Enclosure 2, the licensee has not yet submitted a proposal on a recomended method for disposal of the contaminated water. However, we expect a proposal to be submitted.in early s
d 1980. The NRC will then prepare an Environmental Assessment of the alterna-tives for disposal of this water in order to ensure that the alternative h
selected for' the disposal of decontaminated water is one with which we agree.
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The Assessment will be made available for public coment.
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The H:norable John Heinz."
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Decontamination of the water held in the auxiliary building by the EPICOR-II
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system is continuing. While the throughput of the system has been lower l.
than initially expected, the decontaminated water has a lower level of
!.k residual radioactivity than predicted. The resultant exposures to workers and the off-site population has been lower than those predicted in our Environmental Assessment of the system.
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Finally, with respect to your request to hold public hearings in the Middletown 9
area, public meetings will be held in the Harrisburg-Middletown area during the preparation of the Programatic Environmental Impact Satement. The first such meeting was held on January 29, 1980.
In addition, as outlined in our August 25, 1979 response to your July 20, 1979 letter, the Environ-mental Assessment described above will be released for publi.c comments. and
, the coments will be considered in any decision regarding these activities.
Since October 2,1979, NRC senior staff members responsible for the TMI
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recovery program have participated in periodic briefings on the cleanup activities at Three Mile Island. These briefings are sponsored by the Pennsylvania Department of Environmental Resources to advise public officials, J
the press and the public on various phases of the cleanup operation. We
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have opened an office in the Middletown area to make staff members more
!f readily available to the public and to provide a place for public inspection s
of documents related to the cleanup.
y We believe by these efforts we will keep the public infonned and provide the public the opportunity to comment on significant aspects of the cleanup program.
I hope this provides you with the inforination you desire.
Si
- erely, E
Gw John F. Ahearne
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Enclosures:
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Reactor Buiiding Contaminated
-Atmosphere (Gases) 2.
Water Disposal p
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Atmosphere (Gases) p On November 13, 1979, the licensee submitted its proposal for the disposal of
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3 the contaminated atmosphere in the reactor buiding in a report titled, E
[1 "Three Mile Island Reactor Building Purge-Program Safety Analysis and
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Environmental Report." The licensee examined four options for removal and
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disposal of the contaminated gases, made up primarily of radioactive krypton within the reactor building:
(1) atmospheric purge, (2) charcoal absorption e
e and storage, (3) gas compression and storage and, (4) cryogenic processing j
i and storage.
In addition to these options, the NRC staff examined freon absorption and storage.
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(1) Atmospheric Ve'nting
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The licensee proposed that atmospheric venting be the means used for
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removing the contaminated gases from the reac. tor building.
Atmospheric
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venting consists of releasing the contaminated gases from the reactor building through the plant vent stack (located 160 feet above grade) at f
times when the wind and other meteorological conditions are most V
favorable.for atmospheric dispersion.
The licensee concluded that the 1
venting can be done with no significant hazards to site personnel or to the general population.
One advantage of venting is that it is'less s
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expensive and faster than the other alternatives considered.
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(2)
Charcoal Adsorption and Storage
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!a This method consists of passing the contaminated gases from
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El the reactor building through beds of charcoal where the
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E-radioactive krypton would remain adsorbed to the charcoal.
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t Once deconteminated, the air would be vented to the atmosphere.
The charcoal with the absorbed krypton would be stored. in-g definitely. To decontaminate the large quantity of air in i;
E the reactor building would require 34,000 tons of charcoal o
stored in 450 tanks approximately 12 feet in diameter and 50 g
feet long.
More details on the system, including tihe estimated
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cost and construction schedule, are shown in Table 1.
II (3)
Gas Storage and Compression i
This method consists of compressing the contaminated gas from
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the reactor building and storing the compressed gas in piping.
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e At a pressure of 340 psig, about 150,000 feet of 36-inch pipe
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would. be required to store the contaminated gases.
Storing the contaminated gases at this pressure for long periods of
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time increases the likelihood of uncontrolled releases.
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Cryogenic System y
The contaminated air would be mmoyed from the reactor building, passed through a recombiner to remove the oxygen, and then passed yl through a cryogenic system cooled by liquid nitrogen, Most of the
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radioactive gases, mainly krypton, would be liquified and retained L
K in the cryogenic system, The purified gages would then be discharged
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from the plant via the~ reactor building vent, Periodically, the liquified krypton would be vaporized and stored as a gas, Thefgas would have to be stored for a long period of time, The cryogenic
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systems, if they operated as designed, will remove about 99,9% of the krypton gas, Therefore, a small amount of radioactive krypton will
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be vented with the purified gar, In addition, concentrated krypton p
will accumulate within the system during operation and be stored.
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T Any uncontrolled release of-this radioactivity due to failures could
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E result in higher offsite doses than the controlled yenting, Additional E
details for this system and an' estimated cost construction schedule l
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appear in Table 1.
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(5). Freon Abs'orption In this. system, the contaminated air from the.reactcr building is brought into contact with freon in a packed column where the
. freon absorbs and removes the radioactive krypton from the air,
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-i-vent.
The krypton is then stripped from the freon in the same column if and stored.
As in the cryogenic system, a small amount of radioactive
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krypton would be vented with the purified gases. 'The krypton will i
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require long-term storage.
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, As with the cryogenic system, some of the radioactive krypton will be k;
released with the purified gases. The potential also exists for higher-doses to offsite populations in the event of uncontrolled releases caused by failures. Additional details for the system and its estimates, il cost and construction schedule are shown in Table 1.
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TABLE 1
COMi'ARISION '0F A!!rEllNATIVES FOR DECONTAMINATION 08: TIIE CASSES IN TNI-2 REACTOR BUILDING Charcoal Compression Cryogenic Freon Status of Technology Known Known Known Pilot scale only
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System Complexlty Simple Simple, but Complex Complex Static System, under pressure no pressure
- Cost of installation
$120-160
$50-75
$10-15
$4-10 million million million million
- Time to Install 30-40 r6onths 25-35 months 20-30 months -
18-36 months
- Preliminary. cost and schedule estimates A
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Water Disposal i
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The licensee-has not submitted a proposal for disposal of the decontaminated E:
it water.
We expect a proposal to be submitted early in 1980. As soon as we ll.:
receive the proposal, we will prepare the Environmental Assessment of the
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approach proposed.
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- A number of op'tions are being considered by the licensee. The most direct a'nd' cheapest route is to release water to the Susquehanna River after processing reduces the radioactivity concentrations to those below the
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limits specified in 10 CFR 20 and the dose objective in 10 CFR 50, Appendix I.
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Examples of alternative approaches to river discharge are:
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Store onsite as liquid in large storage tanks. Approximately
{l t1 3 to 8 million gallons of water would have to be stored for the life of the plant.
The cost would be higher than river disposal
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and would not resolve the problem of ultim te disposal of the
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decontaminated water.
( 2)' Allow the decontaminated water to evaporate from a holding area.
T'his method would avoid liquid releases but would result' in the i
airborne release of tritium.
This 'is a lo.w-cost approach but it e
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overflow due to storms and the disposition of nucl. ides left
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behind after the wacer has evaporated.
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Solidify is concrete and either store onsite or ship offsite P
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This is an expensive option that involves E:
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forming large quantities of concrete.
For example, the size
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15 of a concrete slab that would be formed would be 6 inches thick
[j Wr by 235 feet on a side. Approximately 900 shipments would be 2.i, Ef required to move the concrete offsite for disposal.
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