ML19318B974
| ML19318B974 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 06/26/1980 |
| From: | Chilk S NRC OFFICE OF THE SECRETARY (SECY) |
| To: | Sholly S AFFILIATION NOT ASSIGNED, NEWBERRY TOWNSHIP, YORK HAVEN, PA, PEOPLE AGAINST NUCLEAR ENERGY |
| References | |
| CLI-80-25, CLI-80-26, NUDOCS 8006300366 | |
| Download: ML19318B974 (14) | |
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CLI 26 UNITED STATES OF AMERICA NUCLEAR REGULATORY CCt'111SSION CCNMISSIONERS:
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D oJ John F. Ahearne, Chairman p
con %T Victor Gilinsky U50.c Richard T. Kennedy 2
JUN 2 61U
- b Joseph M. Hendrie
'7-k{/]S Peter A. Bradford
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In the l'atter of
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s METROPOLITAN EDISON COMPANY,_e_t,al.
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Docket No. 50-320
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(Three Mile Island Nuclear Station, Unit 2)
ORDER DENYING MOTION FOR RECONSIDERATION OF CLI-80-25 AND ORDER FOR TEMPORARY MODIFICATION CF LICENSE On June 12, 1980, the C mmission issued a "emorandum and Order, CLI 25, which approved purging of the TMI-2 reactor building atmosphere as pro-posed by the NRC staff.
The staff's proposal was described in detail in the
" Final Environmental Assessment for Decentaminatien of the Three Mile Island Unit 2 Reactor Building Atmosphere,"
NUREG-0652, l'.ay 1980.
Tnis purging can be carried out in such a manner (a " slow purge") that the release of radio-active effluents, primarily krypton-85, will lie within the limits allowed by the technical specifications which are part of the TMI-2 operating license.
A faster rate of purging is advantageous, however, for reasons discussed in the l'emorandum and Order.
To permit a faster purge the Cc= mission issued an accompanying Order for Temporary Modification of License, wnich temporarily imposed dose limits in place of the noble gas instantanecus and cuarterly goo 6300 YL 0$
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2 activity release limits contained in the THI-2 technical specifications.1/
Purging of the TMI-2 containment is presently expected to begin on June 28, 1980.
The Commission received on June 23, 1980 a " Joint l'otion for Recon-sideration of CLI-80-25 and Order for Temporary tiodification of License,"
submitted by Steve'1 C. Sholly, the Newberry Township Three Mile Island Steer-ing Committee, and People Against Nuclear-Energy (" PANE").
The Ccmmission has also received a study entitled " Radiation Exposure Due to Venting TMI-2
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Reactor Building Atmosphere," prepared by Bernd Franke and Dieter Teufel of the Institute for Energy and Environmental Research, Heidelberg, West Gemany, for the Three Mile Island Legal Fund, and dated June 12, 1980.
The Franke/ Teufel study, which arrived too late to be included in the administrative record for the Memoranduia and Order,2_/ takes issue with the Commission's conclusion, otherwise widely supported, that the physical health impacts of purging the i
TMI-2 containment as proposed will be negligible.
This study is cited in the 1/
For the period of the purge the codified license will control releases of radioactive gases to the atmosphere by limits on the radiological dose which can result from such releases, in particular by requirements that doses to maximally exposed individuals as a result of purging not exceed 15 mrem skin dose, 5 mrem total body dose, or 20f, of either of those limits over any one-hour period.
Tnese offsite dose limits are in effect equivalent to the objectives set out in 10 CFR Part 50 Appen-dix I, which implement the Ccmmission's policy that radiation doses from nuclear power plants shall be kept "as low as reasonably achievable"
("ALARA").
Tne Commission's Order for Temporary Podification of License thus aimed at achieving the same level of health protection intended by the superseded release limits while at the same time permitting a rapid completion of the purging process.
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The Commission received a very brief handwritten summary of the con-clusions of this study on June 5,1930 but was not given the full report until June 16, 1980.
3 Joint lbtion as evidence of the need for the Ccmmission to reconsider' its deci-sion to pemit purging.
In view of the importance to the public of having accurate infomation on the health risks of purging, the Commission believes it desirable in the short period remaining before the purging begins to make a prompt though necessarily brief response to the Franke/ Teufel study as well i
as to the motion for reconsideration.
Accordingly, we are attaching to this order a review of the'Franke/ Teufel study prepared by the NRC technical staff.
The staff's review confirms that all radionuclides potentially in the containment atmosphere, not just krypton-85, were considered by the staff in its assessment of the environmental impacts of purging the TMI-2 reactor building.
Radionuclides other than krypton-85 will not contribute significantly to offsite doses from purging.
As the staff's review explains in detail, the Franke/Tuefel study erred by selecting a single erroneously calibrated measurement of the radionuclide concentrations in the containment.
This measurement was clearly inconsistent with previously and subsequently measured radionuclide concentrations and gave values too large by factors of ten thousand to ten million.
The correspond-ing dose calculations made by the Franke/ Teufel study are thus gross over-estimates.
Furthermore, the study's concern about meteorological uncertain-ties and possible inadequacy of monitoring appear to reflect unawareness or misunderstanding of how the purging program is to be carried cut.
In sum, the Commission has found that the Franke/ Teufel study provides no reason to modify the conclusion that the proposed venting of the TMI-2 reactor building involves negligible impacts on physical health.
4 Turning now to the motion for reconsideration, we find that the dis-cussion above deals adequately with the first reason offered for reconsidera-tion, that "[t]he Orcers do not consider in any detail the possible presence of radionuclides other than Krypton-85 in the TMI-2 containment atmosphere."
The environmental assessment, as well as the staff's review of the Franke/
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Teufel report, confim that krypton-85 is by far the dominant radionuclide.
In any event, it should be noted that the~ purging will be conducted so that the dose limits established by the Ccmmission's Order for Temporary Modifica-tion of License will not be exceeded.
A continual monitoring of release activity levels and meteorological conditions will be conducted to assure ~
that this requirement is met.
Thus if radionuclide concentrations should exceed presently expected values, this fact would become quickly apparent and releases would be controlled or, if necessary, stopped so that doses will I
remain within the allowable limits.
The Joint fiction criticized what it terms a " radiological assessment" of the health risks of venting as distinct from a "public health assessment" by "public health professionals."
The joint petitioners also appended to their motion a letter from Irwin Brass of the Roswell Park t'.emorial Institute, Buffalo,'New York, to the effect that the genetic damage and cancer risk estimates used by the Ccmmission in assessing the risk of krypton venting i
are out of date and far too low.
The short answer to the joint petitioners' concern about the Ccmmission's assessment that purcing presents no signifi-cant physical health risks is that there was broad agreement with this assess-ment by groups with expertise oriented toward protection of public healtn,
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5 including the flational Council on Radiation Protection and tieasurements, the U.S. Department of Health and Hu. nan Services, and the Pennsylvania Depart-ments of Health and Public Welfare.
The controversial views of Dr. Bross regarding radiation health risks are known to the Commission from previous occasions.
To the extent that Dr. Bross would conclude that purging the TMI-2 containment involves a significant physical health risk, his views are clearly at odds with the spectrum of scientific opinion cited here and in the Commission's Memorandum and Order in support of the contrary conclusion.
The Ccmmission thus finds that the Joint Motion presents no reason to alter the Cer: mission's key determination that the proposed purging of the T!il-2 containment will have a negligible impact on physical health.
The benefits of prompt purging were discussed at length in the t'emorandum and Orde r.
To risk these benefits by selecting an alternative process, which necessarily would involve significant delay and uncertainty, in order to reduce already negligible radiological impacts still further does not strike the Ccmmission as reasonable.
Accordingly, the Commission finds the proposed purging entirely consistent with the ALARA principle of keeping radiation excosuN "as low as reasonably achievable."
The Joint l'otion also urged that the psychological aspects of purging "should be examined more closely" but cited no evidence to contradict the Commission's belief that prompt purging will remove a significant source of psychological stress related to the presence of the discoled Ti1I-2 facility.
The Commission has admitted its lack of expertise in psychology and reccg-ni:es that more review and study might further clarify tne situation with
6 respect to psychological stress at TMI-2.
We remain confident, however, that stress is likely to be minimized by proceeding promptly with a plan that poses no threat to physical health.
The Joint l'otion offers no reason to believe that f Jrther study would change that conclusion.
Accordingly, we are nct persuaded that purging should be delayed for further examination of
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psychological stress.
Finally, the Joint Motion criticized'our finding that the temporary license modification involves "no significant hazards consideration" and therefore may be made immediately effective.
We believe the joint peti-tieners have misunderstood the scope of this finding, which pertains only to the question whether changing the TMI-2 technical specifications from release limits to dose limits involves a significant hazards consideration.
ine dose li.nf ts aim at achieving the same level of protection of public health and safety / and, in fact, do so more directly, since it is the associated doses 5
rather than the radioactive releases themselves which are the focus of con-cern.
Accordingly, the Commission reaffirms its determination that the temporary license modification involves no sign.ficant hazards consideration and may therefore be made effective immediately.
With regard to purging itself, the unmodified technical specifications which allow for purging were adopted as part of the licensing proceeding for TMI-2 after full cpportunity for a public hearing.
There has been extensive public participation a the purging decision through public meetings and ccmments on the environmental assessment.
There has thus been ample S/
See note 1 above.
7 opportunity for members of the public to raise any issue which might have been brought up in an adjudicatory hearing and to present evidence contradictory to the positions of the NRC staff or fietropolitan Edison.
Tne joint petitioners complain that there has been no public hearing specifically devoted to purg-ing, but they have not indicated that any relevant evidence exists which they have semehow been prevented from bringing to the Commission's attention.
Accordingly, since the procedures by which to Ormission's orders were, developed met the requirements of the Atemic Energy Act arid have provided for a thorough consideration of the issues, we reject the suggestion that these orders should be withdrabn on procedural grounds.
For the reasons ciscussed above, the Ccmmission denies the motion for reconsideration of CLI-80-25 and Order for Temporary liodification of License.
It is so ORDERED.
For the Commissi l
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19 F ~ ~5AliUEL J. CHIL h Secretary of the Commission
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Dated at Washington, DC, this 26th day of June, 1980.
' t!SNRC REPORT BY THE JUN 2 61980 q INSTITUTE FOR ENERGY AND ENVIR0;CidNTAL RESEARCH Y
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HEIDELBERG, FEDERAL REPUBLIC OF GE?NANY o
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N//t The NRC staff has made a preliminary review of the findings presented in report titled "Radia' tion Exposure Due to Venting TiiI-2 Reactor Building Atmosphere" submitted by the Institute for Energy and Environmental Research, dated June 12, 1980.
The staff believes that the major conclusions of this report are i
in error and misleading, primarily because ?Sey are based on a highly inflated
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estimate of the maximum rate at which radionuclides will be released during the venting and an apparent lack of understanding of hcw the venting will 'be carried. '
out and controlled.
Heidelbero Findinc No. 1 Previous discussion of the <enting of radioactive gases from TMI-2 has concerned only the noble gas krypton-85, Besides krypton-85, the atmosphere of the reactor building includes a great number of other radionuclides, some of which would be released into the environment during the blow off of the gases.
This could lead to radiation exposures significantly hicher than those caused by krypton-85, The most important radionuclides, which have not been sufficiently considered so far include:
C 14, Co 60, Sr 89, Sr 90, Ru 106, Cs 134, Cs 137, Pu 239', ?u 241 and others.
Even allowing for high filter efficiency, a model calculation for only three of these nuclides showed that population doses would be high enough to cause about three additional cancer cases and an equivalent amount of genetical damage.
Staff Coment The NRC staff's analysis (,NUREG-0662) of the environmental impacts associated with purging the TMI-2 reactor building atmosphere is based on consideration of all radionuclides including noble gases, transuranics, tritium, casiums and cobalts and other particulates.
Air samples are periodically collected and analysed to identify all measurable for=s of radioaccivity, The dominant and controlling radionuclide is Kr-85, Relative to Kr-85, all other i
radienuclides in the reactor building atmosphere are insiginificant contribut to calculated offsite doses from a postulated purge.
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The reactor building particulate samples taken during January through April of this year indica,t.ed Cs-137 concentrations ranging frem 1.2 X 10-8 to 2.7 X 10-10 Ci/cc.
The particulates Co-58, Co-60, Cs-134, Sr-89,
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and Sr-90 were measured at levels on the order cf 10-10 to 10'II ACi/cc c,r were below minimum detectable levels (~10-10 uti/cc) for the instrumenta-tion.
Gross ~ measurements of samples of the reactor building atmosphere
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taken in April of this year indicate transuranic concentrations no higher than 2.0 X 10-10 Ci/cc.
It shculd 'also be noted that, during the postulated '
purge, the reactor building atmosphere will be passed through HEPA filters with.a measured filtration efficiency of at least 99.97%.
The Heidelberg group based its particulate source term (primarily Co-60 and Cs-137), and the resulting dose calculations and health effects predictic'ns, on the highest reported values for the concentrations of these isotopes, ignoring a number of other values listed on the same table (Table 2.1 of the Met Ed reference).
Unfortunately, these single highest 4
7 values, which were a factor of 10 to 10 higher than other reported values, were erroneous.
Particulate concentrations are determined by measuri the total radioectivity in a sample of air passed thorugh the particulate sampler, and then dividing by the sample volume.
In the case of the erroneous values, liet Ed p'ersonnel failed to record the sample volume.
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(Volumes typically were 10 to 10 cc.)
A volume of I cc was arbitrarily assumed by the licensee yielding artificially high' concentrations of Cs-137 ad
-2 and 7.9 # uCi/cc,~respectively). This resulted in Co-60 (1.4 X 10 calculated dose values which are a million too high for these isotopes.
It is unfortunate that these erroneous values were reported.
Nevertheless,
the NRC staff believes that the Heidelberg group used poor judgement in using these values and ignoring the many other, lower values available to it.
In estimating potential exposures and doses, it is properly conservative to use the highest reasonable source term.
However, it is unreasonable to use a single value or set of values when the numerous other reported values, determined both before and after the highest values are consistently so much' lower.
Additionally, the Heidelberg group ignored the staff's discussiciof the most recent reactor building sample data (i.e., sample data through February 1980) which was available to them in the staff's draft Environmental Assessment for Oecontamination of the Three Mile Island Unit 2 Reactor Building Atmosphere, NUREG-0662 (March 1980).
This discussion (see Section 5.0, e
Reactor Building Airborne Activity) indicates that the latest particulate activity levels are on the order of 1 X 10-9,cci/cc.
Finally, since the Heidelberg dose calculations are based on a fallacious source term, they, too, are fallacious.
Heidelbero Findino No. 2 Uncertainties inherent in the meteorological models and dose calculations mean that it is impossible to exclude that in the proposed purge program individual skin doses due to krypton-85 could exceed the 10 mrem limit.
Staff Cc= ment The Heidelberg group's assertions regarding the uncer:ainty of predicting dose from meteorological dispersion characteristics at TMI are ecmpensated
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a for by the'conservatisms incorporated in the actual purge conditions.
Purging the reactor building atmosphere at TMI will be carried out using real-time meteorological measurements, containment ^at=o' sphere'sai@ ling.
radiological effluent measurements, and an elaborate environmental monitoring program.
Operators will control the release rate, and hence the dose rate, based on actual meteorological conditions and these other measurements.
Purging would be stopped at any time that these ccmbinations of measurements and cals1ations indicate possible dose values that begin to approach limiting values which themselves are well below the imposed release limits.
Thus the Heidelberg group's statement (p.11 of the 6/12/80 report) that, give releases of .r-85 during unfavorable meteorological conditions, " skin doses could reach 320 mrem at a distance of 0.5 miles from the stack," is incorrect and appeags to have been made without knowledge of how the purging will actually be carried out.
Purging the TMI reactor building atmosphere will be monitored and controHed to assure that the dose limits: specified by the Commission are not even closely approached, thus acccmmodating the': disc 6ssed:oricartainties.
Heidelberc Findino No. 3 Estimates of health damage should consider not only regional but also global population doses which are an indication of ail health effects caused by the release of radioactivity.
Both can be estimated only with great uncertainty.
The dose effect relation is subject to wide scientific discussion.
We cannot exclude that venting Krypton-85 alone could cause at least one additional cancer case -(probably skin cancer) plus one case of genetic damage within the next century.
However, nothing is known about a potential synergism bedteen krypton-85 beta and ultraviolet radiatica 1
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The results calculated in NUREG-0552 do not exclude the possibility of 1
I one cancer case in the world population within the next 100 years as a result of purging.
The staff has used the most widely recognized radiation risk estimates to determine the probability of cancer or genetic effects in the 50 mile copulation surrounding TMI as a result of purging.
The average risk of radiation induced fatal cancer to individuals in the 50 mile TMI population was estimated to be 5 chances in 100 billion.
Within the world's population, the average risk to individuals, because of further Kr-85 dilution in the earth's atmosphere, would be even smaller than the already negligi ale risk to people withi'n 50 miles of TMI.
The global collective dose of 100 person-rem whole body dose due to Kr-85 (in the Heidelberg estimate) is minute ccmpared to the annual global background radiation dose of 300 million person-rem.
It should be noted that several independent organizations, including the National Council on Radiation Protection and Measurements, the Environmental Protection Agency, the Department of Health and Human Services, and the Union of Concerned Scientist 9 have also concluded that purging would result in negligible public health risks.
Because of the conservatism to be used in controlling and limiting doses, even a possible synergism between beta radiation and ultra violet radiation in skin cancer induction would not be expected to change the health effects picture markedly.
Heidelberc Findinc No. 4 The environmental monitoring program canno ensure that all significant radiation doses to the community as a resuit of decontamination of the atmosphere of the TMI-2 reactor building atmosphere will be detected.
Most measurements are not frecuent encugh and are not made at all in scme i=portant 1ccalities.
Important pathways and radionuclides are neglected.
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Staff Coment The enviornmental monitoring program for the postulated reactor building purge is one o'f the most comprehensive programs ever developed for monitoring gaseous effluents 'from a domestic commercial nuclear power plant.
The program incorporates the expertise and resources of the EPA, DOE, NRC, State of Pennsylvania (including trained community mcnitors ), and the license The program includes the availablity of 6 mobile (3 epa and 3 licensee) monitoring units as well as the DOE Atmospheric Release Advisory Capacity (ARAC) which will provide independent predictions of the dispersion patterns of the krypton gas.. A detailed description of tihe monitoring program is contained in Section 8.0 of NUREG-0662 (final report, May 1980) including the. number and type of radiation monitoring and sampling devices, their frequency of analysis, and the location of the measurements.
An even more detailed report is given in the E?A report, "t.ong-Term Environmental Radiation Surveillance Plan for Three Mile Island," tiarch 17, 1980.
Frem the comments in the Heidelberg finding and in the body of their report, it isapparentthattheyhadconsiderednEitheri.heEPAreportnorthe'fiM1.i4U?J Most, if not all of the Heidelberg group's ccmments and criticisms are addressed in those two reports.
i The radiological environmental monitoring progam will be supplemented by direct measurement via the stack monitor of all gaseous radioactive materials discharged during the purge as well as real time meteorological dispersion measurements (taken at least hourly) from the onsite meteorological tower.
Additionally, the reactor building atmosphere will be periodically sampled during the conduct of the purge to verify the releases measured directly
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by the stack monitor.
In order to verify that no significant amounts of radionuclides other than Kr-85 are released to the environment during purging, sampl'es from the established network of eighteen operating stations will continue to be collected.
Samples in the downwind sector will be collected every day, rather than the three times per week under normal conditions.
In addition at least one sample frcm " control" stations in each quadrant not in the downwind trajectory will be collected and analyzed on a daily basis.
Heidelberc Findinc No. 5 As considerable heal'th damage could be caused by venting the' atmosphere of the TMI-2 reactor building, we strongly advise against this procedure.
The report of the " Union of Concerned Scientists concludes that decontamination is not as urgent as stated by Met Ed and NRC.
Therefore, we strongly recommend that the alternative methods for decontamination proposed by UCS and Prof. Morgan be used.
1 Staff Cocient The NRC staff disagrees that purging the TMI-2 reactor building atmosphere could result in " considerable health damage."
NUREG-0652, " Final Environment Assessment for Decontamination of the Three Mile Island Unit 2 Reactor Building Atmosphere," provides an extensive technical basis for the NRC staff's recommendation to purge the reactor building atmosphere.
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