ML19224B373
| ML19224B373 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 06/14/1979 |
| From: | Porter S PORTER CONSULTANTS, INC. |
| To: | Arnold R, Congel F, Rosenstein M HEALTH & HUMAN SERVICES, DEPT. OF, METROPOLITAN EDISON CO., Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML19224B374 | List: |
| References | |
| TM-0507, TM-507, NUDOCS 7906150015 | |
| Download: ML19224B373 (3) | |
Text
1.,
TMI DOCUMEffrS DOCUMENT NO:
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COPY MADE Op 8~ &[- 7f 0F DOCUMENT PROVIDED BY METROPOLITAN EDISON COMPANY.
Supervisor, Document Control, NRC j
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76 klY T E r.wOLjs! PL ACE 4, g ) P.a O S4 [. p A 19003 21: e ';6 *.,3 5 3 I
MEMO
~TO:
R. Arnold
- L.
Battist, NRC, Bethesda R. Bores, NRC J.
Collins, NRC
- F.
Congel, NRC, Bethesda-J. Herbein
- H.
Peterson, NRC, Bethesda
- M. Rosenstein, HEW, FDA, Eureau of Radiological Health B. Rusche K. Woodward, Pickard 6 Lowe
REFERENCE:
May 10,1979 draf t document entitled " Population dose and health impact of the accident at Three Mile Island Nuclear Station (a preliminary assessment, March 38 to April 7,1979)"
SUBJECT:
Errors made by Ad Hoc Population Dose Assessment Group in computing dose to the maximum individual during the Three Mile Island Acci'ent of March 28, 1979.
1)
_ Errors A) Page 24 of the referenced document lists the Met Ed TLP d a a f or the
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period Dece-ber 27, 1975 through April 6, 1979.
This data constitutes greater than 95% of the dose to the maxima: individual during the Three Mile Island event.
The data listed does not subtract background for the period.
More importantly, the data listed does not correct for the over-response of the TLD's to 81 kev gattna which is a factor of 2.2.
E) The NRC has never contacted Porter-Gertz Consultants, Inc. in order to establish what the specific background is for each of the TLD stations.
C)
The NRC uses the unit mrem which must be corrected for the roentgen to rad dose, as well as for the quality factor.
D)
The maximum individual dose must be corrected for shielding factor for the time the maximum individual was in doors during the event.
E)
The maximum individual dose must be corrected for the proper occupancy time.
It is unlikely that the maximum individual did not move away from TMI bet.een the dates of 3/28 and 4/7/79.
2)
Attempts to Correct Errors in the Referenced Document A)
I have made repeated attempts to have F. Congel of the Ad Hoc Committee '-.
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sit down with me to discuss the interpreNtion of the TMI TLD data'...I had discussed this data with Robert Bores and he agrees with me that the
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embers of the in-agency Ad Hock population dose assessment 01 10
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dose to the maximum individual, as smuted in the referenced document, is incorrect.
I am still attenpting to discuss this data in detail with F. Con!;e1 or one of his Committee members.
E)
I have discussed this item (both last week and this week) with John Collins of the NRC who has promised to attempt to allow Met Ed to review the use of our TLD prior to this draf t document being publised as a new Reg.
3)
Porter-Gertz consultants, Inc. Interpretation o_f TLD Data The potential dose to the maxit,un individual living out of doors 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> per day at the Laurel Road TLD station (4A1) with background subtracted is. equal to 3_0.7_mR for the_ time yeriod of 3/28-5/5/79.
Please refer to the enclosed memo from S. M. Gert to S. W. Porter, dated May 17, 1979 for the details of the Porter-Gertz evaluation of the TLD data.
h,& s./
y/a S. W. Porter, r.
Fead, TMI-Effluent / Environmental Assessment Branch SWP/cr enc.
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rict'-Gertz CenoulfIn:s, Inc.
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'm m. s m M3y 17, 1979 MEMO
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L T0: S.W. Porter, Jr., Head, TMI-Effluent / Environmental Assessment Branch T?iO": S.M. Gertz, Ph.D.
SU3 JECT:
Potential Dose (mR) To The Maximum Individual Off Site In The Vicinity Of Three Mile Island fiuclear Station For The Time Period Of 3/28 - 5/5/79 As Determined By The TMI Radiological Environmental.'ionitoring Program TL D Da ta A. Discussion of Results The results in paragraph E below assume that the maximum individual was sta out of doors 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> a day, 7 days a week.
Therefore this dose needs to be re-duced utilizing a reasonable occupancy factor for the time indoors and the time near station 4A1.
The normal background of station 4A1 is 5.6 mR per standard month, which is equal to 0.184 mR per day, based on 1978 data at this station.
A further correction of the results should be made so that the final r expressed in mrem.
Tiiis correction is normally made by multiplyino the mR by 0.955 to obtain mead.
tiplying by the quality factor, which is assumed to be 1 in most ca E. TLD Results - Raw at 4A1
_12/27-3/29 J3/28-3/29]_
3/29-3/31 3/31-4/3 4/3-4/6 20.2 1.3 3.40 34.3 8.6 41.4 8.5 2.2 0.4 Uncorrected total = 81.3 mR C. Resu'.ts - Corrected for 2.2 overresoonse of 81 rseV 3/_28-3/29 3/29-3/31 3/31-4/3 4/3-4/6 1.65 15.79 19.12 1.30 Corrected Total = 37.9 mR (includes backaround)
All results were background after 4/6.
Total exposure 4/6-5/5 = 3.8 mR D. Correction Formula Net TLD - Ncroal Backoround
-27
- + Normal Background True Dose
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The dose to the maximum individual living out of ~6cors.2T 60urs'per daF at' the
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Laurel Road TLD station (4A1) with backaround subtracted is equal to 30.7 mR
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the tine period of
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3/28-5/5/79.
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Data personally reviewed and verified by Steven M..Gertz, R3.D.-
S.U.~P,jo t g Jr.
Coordinator-TMItiS Emergency Environ-nental Sample Collection & Statistica Wo k.
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