ML17173A754
| ML17173A754 | |
| Person / Time | |
|---|---|
| Site: | Dresden, Quad Cities  |
| Issue date: | 04/16/1979 |
| From: | Janecek R COMMONWEALTH EDISON CO. |
| To: | Ippolito T Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 7904200203 | |
| Download: ML17173A754 (2) | |
Text
Commonwealth Edison One First National Plaza. Chicago. Illinois Addre.ss Reply to: Post Office Box 767 Chicago, Illinois 60690 April 16, *1979 REGULATORY DOCKET FILE CO?Y.
Mr *. Thomas* A. Ippolito, Chief O°Perating Reactors ~ Branch 3 Division of Operating Reactors u.s. NUclear Regulatory commission Washington, D.c.
20555
Subject:
NRC Request for Radiation
.* Measurement In£ormation at BWRs NRC :OOcket Nos. 50-10/237/249/254/265 Reference (a): T. A. Ippolito letter to c. Reed date.d March 19, 1979
Dear Mr. Ippolito:
Reference (a) requested information concerning direct "shine" radiation from mm. turbine*s and plume radiation.
In 1971, commonwealth.Edison contracted with Environmental*Analysts of New York to perform a direct shine survey at Dresden Station, Units 2/3 operating.
The results of this survey are** contai"ned in Attachment l. Later,* the authors combined this Dresden data with data from other BWRs and prepared Attachment 2. This Dresden study is the only one of its kind performed for* us.
However, the former Health and Safety Laboratory of New York has performed studies of plume and, we-believe, direct radiation at Dresden.
Their data should be of interest to you.
With respect to plume radiation, one aspect of the Envircmmental*nose Pathways Study performed at Dresden during L978 was.the measurement of plmne radiation using pressurized argon ion chambers (PICs) and. the comparison of this data to the cloud gamma dose model.
Only data for the August-November period is useful for this purpose.
Preliminary evaluation of the information indicates that the monthly dose (computed from
.either the finite plume model on an hourly basis or the sector average, joint frequency wind rose model on a monthly basis) *is less than the measured dose by about a factor of two.
This under-estimation is believed due to the models assuming no contribution of exposure from plumes in adjacent sectors, when in actua.lity, because of the long relaxation length of gamma radiation in air, there appears to be siqnificant' contributions.
7904200~:;,
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Commonwealth Edison ttc Docket Nos. 50-10/237/249 50-254/265 Mr. Thomas A. Ippolito:
2 -
April 16, 1979 More specifically, if D is the calculated monthly dose at the center of the sector of in~erest, and o1 and o2 are the calculated center-line* doses in the two adjacent sectors, then the measured dose D is at the 95% confidence level, m
- -This formula applies only to an eleyated release to a distance of 3/4 of a mile and should be confiJ:med at other locations and release heights before.general use. *we plan to more rigorously study the finite plume model to see if better agreement with measured data for shorter time periods is possible, but the results will not be available until later this year.
No measurements similar to those indicated above have been made at Quad-Cities Station, so no information from that site is available.
I hope that this information is useful to you.
Please address any questions concerning this matter to this office.
attachments Very truly yours,
~~J Robert F. ~:~~~~
N'Uclear Licensing Administrator Boiling Water Reactors