ML19249F170
| ML19249F170 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 10/26/1973 |
| From: | Benaroya V US ATOMIC ENERGY COMMISSION (AEC) |
| To: | |
| Shared Package | |
| ML19249F153 | List: |
| References | |
| NUDOCS 7910100577 | |
| Download: ML19249F170 (6) | |
Text
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10/26/73 THREE MILE ISLAND NUCLFAR STATION - DOCKET NO.
50-289 Supplemental Testimony on Low Level Radiation Effluent By Victor Benaroya Contention 7 "The low level radiation effluents from the facility are not as low as practicable in that the facility does not have the latest and most up-to-date state of the art available radwaste system for both gaseous and liquid effluents to reduce low level radiation in that one of more of the following should be added:
1.
Treatment by charcoal filter of the main condenser air ejector discharge.
2.
Treatment of the reactor building containment atmosphere by a charcoal filter kidney system.
It is further contended that the calculations of the applicant and tne AEC cannot take into consideration the full radioactive inventory in that the cladding failure, for example, is too conservative, and the additional releases resulting from abnormal transients is not fully dealt with. It is further contended that the low level radiation through the pasture--cow--milk pathway and to infants and pregnant females is not as low as practiccble."
5 77 7910100
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i In our evaluation, we consider the inventory of radioactive materials in the primary coolant to be based eith-on 0.25% or 1% of the equilibrium fission product inventory, depending on the purpose of the evaluation. To evaluate the capability of the radioactive waste treatment facilities to reduce the liquid and gaseous effluents to levels that result in the impact to the environment being as low as practicable, we consider exoected clant operatine conditions. To evaluate the capability of the radioactive waste treatment facilities to reduce liquid and gaseous effluents to concentrations within the limits specified in 10 CFR Part 20, and for shielding requirements to keep doses to operating personnel as low as practicable, we consider the design for abnormal operation of the olant. The release of 1% of the fission product inventory to the primary coolant is the maximum expected value for which the plant is designed to operate. The table below shows that a value as high as 0.7% has been reported, but 1% has rever been reached. However, the release of 0.25% of the fission product inventory to the primary coolant is the average value based on operational experience with Zircaloy clad fuel in pressurized water reactors, similar to Three Mile Island Unit 1.
The c ata upon which this value is derived are as follows: \\4\\\\
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4 Facility Rating Mut Effective Full Power Davs
% Releases Ginna 1300 280 0.4 NOK (Breznau 1) 1142 413 0.7 KEP (Konsai Elec. Co.)
215 215 0.03 Point Beach 1518 100 0.003 H.B. Robinson 2300 75 0.0 Ave.
0.23 Our acceptance guidelines for radiciodine as low as practicable releases are formulated in Regulatory Guide 1.42.
The guide takes into account methods to reduce radioiodine releases, possible treatment of such releases and site characteristics in determining the necessary use of state-of-the-art technology for each application.
Regulatory Guide 1.42 discusses iodine release limits from a site, regardless of the number of units located within that site. There are two units, Unit 1 and Unit 2 in the Tbree Mile Island site.
Our calculated thyroid dose to a chi *.d through the pasture-cow-milk pathway, considering the actual locatior, of the cow 1-1/2 miles east-south-east from the site, is reported to be 19 mrem /yr for both Units 1 and 2 in the Final Environmental Statement, Page V-25.
Of this dese, approximately 10 crem/yr is the contribution from Unit 1.
- However, in our evaluation, no credit was given to the charcoal adsorber in the auxiliary building, because the applicant did not com=it to operate it continuously. However, since this adsorber will need to be used )h\\\\
P if, due to fuel cladding failures, radioactive materials enter the primary coolant system, and simultaneousl'y, some leakage occurs between the primary coolant and secondary system, as assumed above, and therefore credit is given for this charcoal adsorber, and with the revised meteorology as described in Supplement No. 1 to our Safety Evaluation dated October 15, 1973, Page 3-1, the iodine releases from Unit 1 would be reduced from 0.13 ci/yr to 0.06 Ci/yr, with a resulting thyroid dose to a child through the above pathway, of 2 mrem /yr (and 4 mrem /yr from Unit 2).
Since this corrected dose rate is lower than the acceptance guidelines of 15 mrem /yr in Regulatory Guide 1.42, we do not believe that additional equipment, such as charcoal adsorbers to further reduce radioiodine releases from the main condenser jet ejector exhaust, or the installation of kidney filters inside the containment is necessary.
The iodine releases to the environs will be monitored according to the Technical Specifications developed for Three Mile Island. If actual releases exceed the prescribed limits, the licensee will be required to take appropriate action to reduce these releases as delineated in the Technical Specifications.
Adding a charcoal adsorber in the existing filtering system, to treat the exhaust from the main condenser jet ejector, would decrease the I-131 releases from Unit 1 from 0.06 ci/yr to 0.05 ci/yr. This would not appreciably reduce the calculated dose to the thyroid of \\h\\\\
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0 a child from the present calculated 2 mrem /yr and would cost approximately $10,000 (Cost Ref: Appendix D. WASH 1258). To install a kidney filter system to treat the containment atmosphere would cost approximately $140,000, and it would cost an additionai
$5,000/yr to maintain such a system (Cost Ref: Appendix D, WASH 1258). A 20,000 cfm kidney filter s stem, a reasonable size for this facility, would reduce the I-131 releases from Unit 1 from 0.06 Ci/yr to 0.02 C1/yr, decreasing the calculated dose to the thyroid of a child from 2 mrem /yr to 1 mrem /yr. These assumed costs estimates are for new plants, so that the costs would be considerably higher if an existing plant, such as this facility, is to be modified.
In summary, if both a charcoal adsorber is installed to treat the main condenser jet ejector exhaust and kidney filters are installed inside the containment, the thyroid dose to a child from both Units 1 and 2 would be reduced from a calculated 6 mres/yr to 5 mres/yr at a cost in excess of $150,000.
One should also bear in mind that when additional equipment is added to an existing radwaste system it is difficult to provide adequate shielding to protect operating personnel from operation and maintenance of the components. Thus, further modifications and additions to the radwaste system of Three Mile Island Unit 1 at this stage, probably will increase the dose to the operating personnel. )k)\\
Based on our analysis on the expacted cost for additional equipment and the probable increase of dose rate to operating personnal, for the small potential expected reduction in the calculated thyroid dose to a child, we do not recommend at present further modifications to the existing radwaste systems of Three Mile Island No. 1, since the applicant has provided radioactive waste treatment facilities that are capable of reducing effluents to as low as practicable levels in accordance with Staff guidelines.
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