ML19261A241
| ML19261A241 | |
| Person / Time | |
|---|---|
| Site: | Haddam Neck, Millstone File:Connecticut Yankee Atomic Power Co icon.png |
| Issue date: | 01/18/1978 |
| From: | Hendrie J NRC COMMISSION (OCM) |
| To: | Dodd C HOUSE OF REP. |
| Shared Package | |
| ML19261A242 | List: |
| References | |
| NUDOCS 7810140039 | |
| Download: ML19261A241 (2) | |
Text
4 JAN 18 1978 D**]D *D T
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The Honorable Christopher J. Dodd United States House of Representatives Washington, D. C. 20515
Dear Congresstran Dodd:
This letter is in response to your letter of November 15, 1977, requesting the Nuclear Regulatory Commission to evaluate a report submitted to you by Dr. E. J. Stemglass concerning strontium-90 and cesium-137 in milk frun farms near Connecticut nuclear power plants.
Based on a preliminary review of the report, we cannot establish any relationship between the somewhat elevated level of radioactivity in the milk and the operation of the nuclear power plants.
This conclusion is primarily based on our review of tir licensee's periodic radioactive effluent and environmental monitoring reports.
This situation has also been examined in detail by the NRC Regional Office responsible for the Millstone and Haddam Neck plants. The Regional Office confirms this analys is. The conclusions of Dr. Sternglass that the levels of Sr-90 and Cs-137.are of plant origin are unsubstantiated by the data.
All effluent releases from the facilities are continually monitored and controlled to account for all radioactivity released to the environ: rent and to limit the quantities released.
The treasured Sr-90 and Cs-137 releases from the plants were insignificant in terms of calculated environmental radiation doses and could not result in the levels of radioactivity measured.in the milk.
The relative absence of Sr-89 and Cs-134, which are released in reactor effluen+s in comoarable quantities as'Sr-90 and Cs-137, provides additional verification that the levels are not plant-related.
In any event, regardless of the source of radioactivity, Dr. Sternglass' extrapolations to population doses and related health costs are incorrect.
His assumptions of total diet intake of radioactivity and exposed popula-tions are unrealistic and overestimate the actual population doses.
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The Honorable Christopher J. Dodd A cet' ailed respe,nse to the full report will require several months to prepare.
However, on the basis of cur preliminary review, we have addressed the three specific questione. asked in your November 15 letter.
L'e trust that the enciesed is responsive to your concerns and cuestions.
Upon completien of the requested in-depth evaivation of Dr. Sternglass' report, a.mre detailed assessment of the situation will be provided to you.
Sincerely, Cri;ing; gi;;.g 3,y Josy;- ?L a,,.;,,q.
Joseph M. Hendrie Chairman
Enclosure:
Preliminary Evaluation of Dr. Sternglass' Report e
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PRELIMINARY EVALVATIO:1 0F DR. STERNGLASS' REPORT,
" STRONTIUM-90 LEVELS IN THE MILK AND DIET UEAR CONNECTICUT NUCLEAR POWER PLANTS" D**D D
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_0uestion "Do you consider the amounts of strontium-90 found in the milk and diet around the Connecticut plants to be unrelated to plant operations?
If so, why?"
Answer The appare.nt high levels of Sr-90 in the milk around the Connecticut plants are unrelated to plant operation, based on our review of the licensees' reported radioactive effluents and environmental monitoring data.
This apparent anomaly has also been under examination over the past several years by the NRC Inspection and Enforcement Regional Office responsible for the Millstone and Haddam Neck plants.
The Regional Office has not been able to establish any potential pathway of environmental transport from the Connecticut plants to the milk which would account for the levels observed.
All effluent releases from the facilities are continually monitored and controlled to account for radioactivity released to tha environment and to limit the quantities released.
The NRC Regional Office has examined the licensees' radioactive effluent monitoring and control procedures, including sampling and analytical methods and quality control procedures.
Also, the IRC conducts a radioactive effluent sample splitting program with the licensees' to provide additional verification of the accuracy of the licensees' measured effluent quantities.
In this way, we are assured of the accuracy cf the licensee-measured radioactive release values.
For 1976, which is the 2158 190 D)(
L year of highest measured milk values, the measured radioactive efflue it relehsed from the facilities could have'resulted only in a very low levcl of contamination, amounting to less than 0.001 picoCuries per liter of milk, which is less than one-thousandth of the value measured in the milk.
Thus, the measured Sr-90 and Cs-137 releases were insignificant in terms of calculated environmental radiation doses and could not result in the levels of radioactivity measured in the milk.
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The absence of strontium-89 indicates that the radioactivity is not from reactor facility releases.
Sr-89 behaves chemically and biologically the same as Sr-90 and is more abundant than Sr-90 in reactor effluents.
If the levels in milk were a result of facility releases, then the quantity of Sr-89 should exceed the levels of Sr-90; however, this was not the case.
Sr-89 has a relatively short half-life (50 days) compared to Sr-90 (28 years).
Therefore, the absence of Sr-89 indicates that the measured levels of Sr-90 in the milk are a result of radioactivity that originated at least several years ago.
Similarly, the relative absence of the shorcer half-life Cs-134 (2.1 years) and 1-131 (8 days) that are also released from the facilities in comparable quantities indicates that the radioactivity in the milk is not from plant operation but appears to be fall-out from past nuclear weapons tes ting.
As expected, a short-term increase in Sr-89 levels was observed follcwing the Chinese weapon test in 1976.
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Ouestion 1
"Are levels of strontium-90 taken into account when federally regulated k
j testing of the environment around the nuclear power plants takes place to i
measure controlled substances?
If not, why not?"
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Answer The releases of radioactivity from nuclear power plants are measured and
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In additien, the f1RC also requires sampling of the environs
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around reactors to verify the in-plant controls and provide reasonable F
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assurance that the predicted environmental doses (based on measured radio-j?
Y active effluents) are not substantially underestimated and are in compliance l-5 with applicable standards, g;
i Strontium-90 is routinely evaluated in both the radioactive effluent 5-E releases and the environmental sampling media at Millstone and Haddam Neck.
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The radioactive effluents and measured levels of radioactivity in the environment around. Millstone and Haddam lieck are routinely reviewed by the 5:
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!!RC.
If abnormally high levels of radioactivity are measured either in the g..
plant effluents or the environmental media, an NRC review of the situation
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is conducted to identify the cause and determine if any corrrective action j;
W-is needed.
The Sr-90 in the milk from farms around these facilities has
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been determined not to be of plant origin.
Therefore, no plant corrective E.
actions would improve the situation.
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_4 On the basis of our analysis to date of nuclear power plant radioactive effluents and the important environmental dose pathways to man, we have concluded that neither Sr-89 nor Sr-90 are significant dose contributors to man from normal plant operation.
tiRC guidance on requirements for radiological environmental-monitoring is therefore being revised to celete the routine. analysis for Sr-89 and Sr-90 in sampling media.
These r.uclides, however, will continue to be monitored in r~ ant effluents.
For selected plants, where elevated environmental levels of Sr-90 have been detected in the past or where unexpected high levels of Sr-89 and Sr-90 are found in effluent releases, the need for environmental sr pling and analysis will be determined on a case-by-case basis.
We anticipate.that teasurements and analyses of the relative amounts of Sr-89 and Sr-90 will continue to be required around the Millstone and Haddam tieck facilities to provide continued assurance that the environmental radioactivity levels are r.ot the result of plant operation.
Guestion
Are the levels of Sr-90 calculated by Dr. Sternglass accurate?
Do the professor's extrapolations, in terms of the total bone and body doses received by the population surrounding the plants, have scientific validity?
If not, why not?"
Answer The levels of Sr-90 in the milk around Millstone were measured through the routine raciological environmental monitoring program conducted by flortheast Mi'ities.
Based on our evaluation of the monitoring program to date, we 2158 193
believe that the measured levels of Sr-90 are accurate.
Dr. Sternglass used these measured values as his starting point in determining the plant-related individual and population radiation doses.
However, as already ciscussed, the Sr-90 is not a result of Millstone operation.
Therefore, the professor's extrapolations, in terms of plant-related radiation doses, are a substantial misrepresentation of the envi onmental impact of plant cperation.
Koreover, the methodology of dose calculation employed by Dr. Sternglass is overly conservative.
The professor's assumptions of total diet intcke of St-90 and exposed populations are unrealistic and overestimate the actual population doses.
Dr. Sternglass' calculational procedures will be addressed in more detail by the NRC in a detailed critique of the full report at a future date.
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}9 The Ho.norable Christopher J. Dcdd United States House of Reoresenutives Washincton, D. C.
20515
Dear Congressman Dodd:
At the recuest of the Nuclear Regulatory Comais51on, Dr. Marvin Gold an, h
an MRC consus tant, performed an edcitional review of the ailegation raised by Dr. Sternglass concerning the level of strontfu: and cesf ue in the en-j-
virornent around nuclear facilities in Connecticut.
Dr. Gol dan's con-clusion is supportive of our previous review of this subject, which was L
provided t.o you by letter dated January 18, 1978 from Chaiman Hendrie-D 5:.
Dr. Golamen is presently the Director of the Radiobiology Laboratory, t:
University of California-Davis and is retained by the NRC as a scientific t.
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consul tant.
Dr. Golccan is a member of the National Council of Radiation F
Protection (NCRP) ana the New York Academy of Sciences. Addi tional ly, I
Dr. Golchan has served on advisori comittees for the Food and Drug Ad-h riinistration's Bureau of Radiological Health and the National Acadecy of
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Science's Ad Hot Committee on " Hot Particles."
Dr. Gold:an's expertise in the area of envirornental radioactivity and radiobiology is further l
exe;:plified by his being the recipient of the AEC's E, O. Lawrence Award for 1972 for contributions to the "understar. ding of ~ the effects of bone-seeking radionuclides, in particular, the quantitation of the metabolic, dosinetric and carcinogenic characteristics of long-tera strontico-90 I!
exposure."
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Ve consider the enclosed evaluation of the Sternglass report a fulfillment l'
of our cow ment to you to exactne in cetail the findings of Dr. Sternglass.
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Most radiobiologists assume that there is soce risk associated with any I
radiation exposure, regardless of how small.
We feel the risks from expo-(
sure to the very Icw levels of radiation associated with the routine opera-tion of nuclear power plants such es those in Connecticut are extremely small in relation to the other co:peting risks associated with living a useful and satisfying life.
Nevertheless, we recognize that such judgr4ents are value judgroents, and others tsay not always agree with our perception of the risk inVolYed.
l cN'h[ld ty li. ;;. 0:rlen I
Harold R. Denton, Director Office of Hucitar Reactor Regulation 2158 195 e
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U. S. Nuclear Regulatory Co==ission
-:2 tu FR3M: Dr. Marvin Goldman en F..
RE:
Recent reports of Dr. Ernest Sternglass regarding radioactivity and health statistics around nuclear facilities in Connecticut.
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I was asked to serve as a censultant to the Nucicar Regulatory Comission in j
this catter and to review and coc=ent upon two reports by Dr. Ernest Sternglass.
I One is " Strontium-90 Levels in the Milk and Diet near Connecticut Nuclear Power f~
P.lants," dated October 27, 1977, and the other appears to be testimony dated Februa y 10, 1975 for a Congressional seminar and is titled " Cancer Hortality
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Changes A cund Nuclear Facilities in Connecticut." Although I a= Director of a large radiobiology laboratory at the University of California, the views ex-p essed herein are entirely my own and in no way imply any endorsement or assess-tent 'cy the University of California or the Federal agencies who support the Laboratory's research.
Fcr the past 27 years I have been engaged in radiobiologic research related to the dosimetry, netabolism and pathology of radionuclides.
In particular, a r.ajer effort involves studies of radiostrontiu and its effects.
M. Sternglass alleges that levels of strontium-90 (physical half-life of ebeu: 23 years) and cesium-li7 (physical half-life of about 30 years) around iacia: Neck and Mi11stene Point nuclear power plants have been increasing mark-edl;. as a result of plant emissions and that these levels pose a " serious threat
.o h=an health."
I do not agree with these conclusions.
In reviewing the information avail-61e ro ne I conclude cuite the contrary.
Tnere are several reasors that prompt
_e to seriously cuestion the validity of Dr. Sternglass' conclusions.
Cr.e central factor relates to the well knowr. fact tha: Sr-90 and Cs-137 are en;
- ved fission produe ts resulting fro the fissioning of fertile elements
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u c'r. a s U-215 an d Pu - 239.
Furthermore, it is also well docurented that as a escit cf atmospheric weapons testing (especially sone 15 years ago) that the
.: ire.and surface of our plane: is, to a variable and freo,uently measured er ee, cen acinated with low J evels of these (and some other) radionuclides, t is a*se knowT4 that when tranium-235 is fissioned, a host of radionuclides of s.r;'in; ' alf-lives are generated.
"inis is true of both weapons related fission-
.; and cf nuclear fuels in an operating reacter.
One additienal fact that 2158 196 L
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Dr. Sternglass see=s to have not taken into account is t' at recent fission product h
mixtures will contain short lived radionuclides as wel) as long-lived radionuclides.
The fraction of short-lived radionuclides will decline with time after fissioning and a: late times only the Icag-lived species uny bc cstected in envirom catal samplas. Tnis ebD ity to " data" M radioanivity, c-st 2 eist eenNm it is cf recent origin is an impoz tant and relatively " fool proof tool."
Tna: Sr and Cs both exist in freshly produced firsion products in the fom cf several isotopes is fortuitous and significant. Generally speaking, consider-3 ably core "short-lived" Sr-89 (half-life s50 days) is produce,d and to a limited ext e n: released than the longer-lived Sr-90 In terms of relative activity, de-pending on sampling time, Lbou: 5 pCi of Sr-89 might be released for each pCi of Sr-90.
Tnus even correcting for the decay of radioactivity from " release" to incorporation into the food chain (e.g., milk and other locally pwduced food stuffs), there must be some Sr-89 present in foodstuffs with Sr-90 of recent origin.
Tne nuclear plants do record the annual totals of both strontium iso-topes released and do record the levels in their periodic environmental samples.
If this is true, my question is where is the Sr-S97 Tne methodolcgy seems to be sufficiently sensitive to have picked this up following some Chinese atmospheric weapons tests; enth S -89 and Sr-90 (e.g.,10/5/76 samples of tilk which also showed 8 day Is131) were measured.
Furthermore, the alkali earth element cesium is represented by shorter-lived isotopes, particularly the 2.1 year half-life Cs-134 This isotope is released along with the Cs-137 from nuclear reactors in very small quantities (e.g.,1972 Millstone 16.4 Ci Cs-137 plus 8.6 Ci Cs-134). Tne activity ratios are similar -
about the same number of microcuries of each isotope released annually.
Since their respective decay emissions are sufficiently different, any detector sensitive enough to identify one can distinguish it from the other - their gamma ray and beta particle energies are different. Tnus, I must question the conclusion tha:
the Cs-137 measured in food stuffs was recently released from the nuclear plant in question.
If so, where was the Cs-134? Tnere are no pathways to man which separate these two isotopes of the same element.
The element cesium will behave like cesium whether it is Cs-137 or Cs-134 Tne element strontium will behave like strontium whether it is Sr-90 or Sr-591
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In light of the fregaen: sampling schedults, it is not possible for the short-lived radioauclides to have decayed to non-detectable levels relative to thos e measured for the longer-lived isotope.
inus, I am forced to conclude that the vnly explanation for the data shown is that whatever the nuclear plants re-leased was completely masked by the " background" level of Sr-90 and Cs-137 from fairly old atmospheric deposits, i.e.,
earlier weapons tests.
Tne Sr-90 and Cs-3 37 shown in national monitorng data varies from place to place and with time.
In food stuffs, some of the variation is related to the degee of frerh foliar deposition on vegetation and cattle ferage as well as root uptake frc soil deposits.
In addi don, the local rainfall pattern may " wash on or off" varying amounts cf atmospheric fallout on vegetation surfaces, as well as leaching more deeply into the soil that which was deposited on the surface.
Globally, millions cf dollars have been spen on studying and quantifying these phenorena and their variations.
Depending on how one calculates a mean or average value, individual samples may vary by ten fold in repeated sarpling l
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(co: pare tilk Cs-137 in April vs. May 1976 for U. S. cities).
The time trends a.d specific levels have shown me no significant levels which I feel can be attributed to plant releases. On the contraa, the data strangly indica ce that
%e Sr-90 Pnd Cs-H r:.nsur d '.n foed p..hwa. sr.tpic. cre alem. all, if not c: tire 17, the result of atmospheric weapons test fallout.
A fatal flaw in Dr. Ste:. glass' analyses is the t.nner of selection of da ta. One cannot select a particular simple as meanin ful unless the other s:cc:.anying radionuclides are all present and the environmental pathway moni-tering is conristent. Tnus, for rilk to contr.in nuclear plant Sr-90 and Cs-137,
- cust also have the other nuclides, Cs-134 and Sr-89 (and I-131 I night add).
These findings would have to be confirmed by air and liquid samples and the plant monitors would also have to have 'shown "down stream" increases.
I do not find support for these requirerents and conclude that the local measurements a.re refle:tiens of the local temporal weapons fallout situation.
Ancther prcblem o# apparent misinterpretation of data relat es to the re-P:rting of cancer death rates. Cco.aecticut probably has one of the best state t=c registries in the ccuntry and I w;uld imagine that the State officials may have their own analyses of the trends of cancer mortality.
I reviewed the gen-e al statistics on cancer published annually by the American Cancer Society in ats " Cancer Facts and Figures." For example, it was of interest to note that i the Unit.ed States, overall cancer nortality has steadily risen from about 160 pe-hundred thousand in 1970 to about 170 per hundred thousand in 1975.
Tne ACS publirhed annual Connecticut rates which are generally in agreement with these value s.
I did not check on the State registry as I wished to determine whether the State was following a different trend than the Nation.
Tne data for both rennecticut and the U. S. show increases which are largely influenced by the neretses in both sexes of lung cancer related to cigarette smoking.
If Sr-90 was indeed increasing, and it does not appear to be the case, its deposition in the body would incur an increased dose to bone and marrow.
- s an alkaline earth element which concentrates in skeletal mineral as does calcium, about one thousand fold creater than in other tissues. Extending this hypothetical si;ustica further, one might have expected an increase in bene cancer and leuke:ia we e sericus skeletal and carrow irradiation resultant from radionuclide burdens.
anere is no cata in support of this.
I calculate that between 1 and 3 mrem per yetr s absorbed by adults and children respectively from tilk containing a cen-stant pico:urie of strontium-90 per liter.
If I accept a cilk concentration of M
chut 10 p:i Sr/ liter, this would account fer about 10-30 tre: per yer_r to bone F.ni ab:ut 3-10 trem per year to marrow.
Tnis value is close to that which we all re:eive from the traces of radium present in our drinking water.
Fna: health effects tight result from skeletal irradiation associated with S:-907 Tne National Acade y of Sciences estinates that about 0.2 bone cancer derths per year would be expected per population of one tillion per rem absorbed.
Tnis w:ulc translate in a Connecticut population of about 3 tillion to 0.6 bone ca cer ceaths per year per rem and also to 0.6 cases tires 0.03 rem (30 trem) er 0.CE cases per year a tributable to the 5 -90 skeletal dose.
Using these ccas e-catice estirates, one would predict abou: 1 such death every fifty years
- secuer.: to a 33 trem bene dose added to the State 50 year total of 1000 to 2 0. d ea ths fro this disease (I estimate a bone cancer death rate of about 1 00R B Md 2158 198!
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,i pe-103,000 per year in Connecticut; i.e., about 30-4 0 per year). There are c:ner ways of cal,.'lat?.rg :cdiation c:n=e: ri.:ks, het I f r.:1u'ed this erample te put the risk per absorbed dose cuestien in perspective and in 7 fo n which is fre uently used by experts in this field.
It is not possible for Sr-90 body k-den.s deri ed by irytie - te iqure can~ers h ct5 r enar
- 0 the cnclusien cf bene and marrow since the radioelenent cone,entrates so preferentially in s>; ele:7.1 tineral.
v In cenclusion, I have not found support for the contention that the Connect-icut r.:c1 car plants have released sufficient radionuclides (Sr-89, 90 and Cs-137, 1 24) t: have caused significen: radiation exposure of the population; such expo-cu es are a minute fraction of those attributed to atmospheric nucicar weapons tests. Furthermore, the radiation doses associated with Sr-90 (from all sources) are very significantly below those associated with observable changes in cancer risk. As a final note, it is generally cepted by the National Acadeny of Sc!en:es that bene cancer risks from prio2 radiation would be acconpanied by r.
laten period of about 15 years, and not six years.
I can only conclude that-the variations in health statistics presented by Dr. Stern 3) ass, if correct, are associated with events totally unrelated to the operation of the nuclear power plants in Connecticut and that there is no evidence to support the allegation that these plants have posed a " serious threat to human health."
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