ML15112B008
| ML15112B008 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 03/31/1981 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML15112B007 | List: |
| References | |
| TAC-54862, TAC-54863, NUDOCS 8104090189 | |
| Download: ML15112B008 (6) | |
Text
o UINITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 SAFETY EVALUATION AND ENVIRONMENTAL IMPACT APPRAISAL BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO.
95 TO FACILITY OPERATING LICENSE NO. DPR-38 A
MENDMENT NO.
95 TO FACILITY OPERATING LICENSE NO.
DPR-47 AMENDMENT NO. 92 TO FACILITY OPERATING LICENSE NO. DPR-55 OCONEE NUCLEAR STATION, UNITS NOS. 1, 2, AND 3 DUKE POWER COMPANY DOCKETS NOS.
50-269, 50-270 AND 50-287 introduction By letters dated May 19, 1980 and December 17, 1980, Duke Power Company (DPC or the licensee) submitted a request to dispose of radioactively contaminated waste oil by incineration in the auxiliary boiler at the Oconee Nuclear Station. Oconee currently has the oil in storage in 55-gallon drums.
It is contaminated with isotopes of cesium and cobalt. The sources of this oil are the turbine building sumps and the reactor coolant pump (RCP) motor oil.
The RCP motor oil-is chnged every two years and generates approximately 1,000 gallons of waste oil for each Oconee unit. The licensee wants to dispose of the oil because the stored oil is an onsite radiological and fire hazard and there is a lack of adequate storage space.
The low level waste disposal sites will not accept unsolidified contaminated oil.
DPC provided the specific radionuclides present in each drum of oil, and the respective concentrations. The predominant isotopes present are Cs-134, Cs-137, Co-58 and Co-60.
The licensee's radiological assessment addressed airborne release pathways for normal conditions.
After evaluating alternatives, the licensee's con clusion was that incineration prov 4ded the best means of disposal.
The licen see did not provide an assessment of accident conditions where a fire may burn a portion or all of the oil.
Also, consequences of liquid spills were not addressed in the request.
We have conducted an independent review and evaluation of the potential radio logical hazards associated with incineration of the slightly contaminated oil in the auxiliary boiler.
810 4090 /I
-2 I. Safety Evaluation Radioactive Release Considerations Airborne releases will take place during normal operations of the auxiliary boiler. The pathway for these releases will be the stack. The contaminated oil that is fed to the boiler will be diluted with fuel oil.
Table I shows the data supplied by the licensee that was used in performing their radio logical assessment. We found these data to be acceptable and they were used to performf our assessment.
Our assessment has shown that if all the radioactivity that is contained in the oldest 24 drums of waste oil, which has the lowest concentration of radio activity of the stored oil, is released to the atmosphere through burning, the quantity of radioactivity released would be less than 0.003% of the annual Technical Specification (TS) airborne release limits at Oconee. Also, the amount released would be only 0.11% of the total amount of particulate activity actually released during normal operation for 1979.
The analysis also showed that the average concentration of radioactivity leaving the stack every second would be 18% of the 10 CFR 20, Appendix B, Table II limits and the highest concentration of radioactivity leaving would be 53% of the limits. We are adding a TS which will limit any future incinerations of waste oil to radio activity levels equivalent to the oldest 24 drums described in the May 19 letter, and more stringent than 10 CFR 20 limits for gaseous effluent releases..
Dose Control Onsite/Offsite Potential onsite radiation dose problems are minimized by the small quantities and concentration of activity present.
The dose rates at the surface of the drums from the contained byproduct materials will be less than.0.06 mrem/hr.
Consequently, the contaminated oil will present no dose problems as long as it is properly contained.
A spill of the contaminated oil could produce both surface and airborne containa lion. However, the surface contamination would not exceed 400 dpm per 100 cm which is 40% of the limit for release for uncontrolled use as found in Regula tory Guide 1.86. The low concentration of radioactivity in conjunction with the normal radiation control practices should preclude any significant doses from surface contamination.
Hypothetically, the offsite maximum-permissible concentration (MPC) could be exceeded by accidentally burning the undiluted contaminated oil.
With per fect combustion, the offsite MPC of 10 CFR Part 20, Appendix B, Table II, could be exceeded briefly by a factor of five, but in an accidental fire, only a small fraction of the oxygen in the air would react so the activity con centration would not be expected to exceed the offsite MPC value.
Exposure time will be limited; exposure to the airborne contamination from the burning of the most contaminated drum.of oil will be expected to produce a whole body dose commitment of less than 0.0006 mrem during normal operations.
The licensee proposes incineration of the waste oil diluted with the boiler fuel oil.
The potential for offsite radiation exposure develops when the oil is burned in the auxiliary boiler.
The oil is to be burned at a rate not exceeding 5.0 gal/min
"3 while the stack flow rate is 100,000 cfm, see Table I. The radioactivity con centration in the stack will not exceed 250 pCilm, which is approximately 53%
of the offsite MPC. A drum of oil would burn in 11 minutes. Exposure to the undiluted stack exhaust for the entire period would amount to 3.1 MPC-minutes.
The average level of activity in the drums is about one third the maximum. Con sequently exposure to.the undiluted stack exhaust during the burning of. the entire oldest 24 drums of oil would constitute an exposure of 25 MPC-minutes; the calcu lated corresponding whole body dose commitments are:
Adult:
C.01 mrem Teen:
0.007 mrem Child:
- 0.
003 mrem Infant:
0.001 mrem Our assessment showed that a reasonable criteria for burning would allow the concentration to reach 0.5 times MPC and permit burning for six hours per quarter. By doing this, the exposure to undiluted stack exhaust during the entire quarterly burn period would amount to a maximum of 120 MPC-minutes and the corresponding doses would be seven times the doses given above (0.07 mrem to an adult, etc.).
Of course, such direct exposure to stack exhaust is not possible and actual offsite doses would be lower by a factor of ten or more.
We conclude that the incineration of waste oil, subject to the TS restrictions discussed below, in this manner will not result in unacceptable offsite doses, and burning this oil is consistent with the NRC principles of, "as low as reasonably achievable" of 10 CFR 50.36a. The Commission, therefore, grants approval of the disposal of slightly contaminated oil by incineration in accordance'with the provisions of 10 CFR 20.305, subject to the TS restrictions discussed below.
Technical Specification Change The proposed TS provides for conservative rates of radiation release by:
- 1. limiting radioactivity In any 55-gallon drum to 10 CFR 20 - Appendix C
- levels,
- 2. limiting rate of incineration-such.that stack concentration of radio activity is one-half of 10 CFR 20 - Appendix B, and
- 3. limiting period of burning to six hours in any calendar quarter.
We conclude that this TS limits the effects of incineration of slightly contaminated oil to acceptable levels.
-4 Conclusion on Safety We have concluded, based on the considerations discussed above, that: (1) because the amendments do not involve a significant increase in the probability or consequences of accidents previously considered and-do not involve a signi ficant decrease in a.safety margin, the amendments do not involve a significant hazards consideration, (2) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, and (3) such activities will be conducted in compliance with the Commission's regulations and the issuance of these amendments will not be inimical to the common defense and security or to the health and safety of the public.
II. ENVIRONMENTAL IMPACT APPRAISAL Radiological Impact As stated above in the Safety Evaluation, the Duke f1ay 19, 1980 request, with the limits established in the TSs, will provide reasonable assurance that releases of radioactive material.will be sufficiently low during normal operations to meet 10 CFR 20, Appendix B limits.
Radiation Dose Impact The total radioactivity contained in the oldest 24 55-gallon drums of slightly contaminated oil is 31.85 pCi, see Table I. The highest radio activity in any single drum is 4.12 vCi.
Occupational exposure in handling the drums during the incineration process has been assessed in the above e
Safety Evaluation along with an assessment of doses.
The impact is expected to be less than 1% of siation exposure limits.
The TS change provided by these amendments will limit the activity in future drums of contaminated oil, prior to incineration, to levels equivalent to the oldest 24 drums.
As stated in the above Safety Evaluation, the highest offsite whole body dose commitment.from burning all 24 barrels of this slightly contaminated oil would be 0.01 mrem for an adult. Since our calculations of the dose commitment contain the consprvative assumotions that, 1) 24 barrels of oil are burned at one time (the proposed TS limits burning to six hours in any calandar ouarter), and 2) the stack exhaust would be undiluted at the time of such burning (the proposed TS limits the rate of incineration to 0.5 times 10 CFR Part 20), the calculated value of 0.01 mrem is considered to be quite conservative.
In the Final Environmental Statement (FES) related to the operation of the Oconee Nuclear Station, the staff calculated the estimated annual radiation dose to the population, in a two mile radial distance from the facility, to be 0.25 mrem/yr from gaseous effluents released by the three reactor units at the Station, (FES, Table V-4, page 124). Therefore, we find the offsite dose consequences of burning the slightly contaminated oil to be considerably less than the yearly, estimated radiation exposure to the population from routine releases. The numerical guides for meeting the "aslow as reasonably achievable (ALARA) criterion contained in Appendix I to 10 CFR Part 50, specify 15 mrem as the annual objective for radioactive material in particulate form to be released from
-5 nuclear reactors. The annual dose commitment as a result of burning this oil plus the dose contribution from gaseous effluents released by the three reactor units at the station, will therefore, be still well within.the guidelines set forth in 10 CFR 50, Appendix I. Since the additional restrictions required by the TS provide an additional degree of assurance that the radiological consequences of burning this slightly contaminated oil will be minimal, we find, in accordance with 10 CFR Part 20.305, that the burning of this sliqhtl.V contaminated oil is an acceptable means of disposal.
Conclusion and Basis for Negative Declaration On the basis of the foregoing, we conclude that there would be no signifi cant environmental inipactuattributable to the proposed burning of such slightly contaminated oil.
As a result of this conclusion, the Commission has further concluded that no environmental impact statement for the proposed action need be prepared, and that a negative declaration to this effect is appropriate.
Dated:
March 31, 1981
TABLE I DATA USED FOR RADIOLOGICAL ASSESSMENT Maximum Amounit of Radionuclides Present In the 24 Drums of Oil Co-58 1.08 Ci Co-60 1.39 vCi Cs-134 6.52 VCi Cs-137 22.86 pCi Total 31.85 pCi Total Oil Feed Rate to Boiler = 18.8 gal/min.
Percentage of Contaminated Oil = 5gpm/18.8 gpb = 27%