ML20246B289
| ML20246B289 | |
| Person / Time | |
|---|---|
| Site: | Fermi  |
| Issue date: | 04/28/1989 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20246B071 | List: |
| References | |
| NUDOCS 8905090005 | |
| Download: ML20246B289 (6) | |
Text
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,THE OFFICE OF NUCLEAR REAC_ TOR REGULATION SAFETY EVALUATION SUPPORTING AMENDMENT NO. 9 TO POSSESSION-ONLY LICENSE N0. DRP-9 ;
FERMI UNIT NO. 1 DOCKET NO. 50-16 ; i i
1.0 INTRODUCTION
Fermi 1 is a 200 megawatt (thermal) sodium cooled, fast breeder reactor that operated from Au 23, 1963 to its final shutdown on September 22, 1972. Detroit Edison (gustthe licensee) estimates the reactor operated for no more than 6000 megawatt days. _All fuel and Uranium-238 blanket material has been removed -l from the site. All sodium has also been removed from the site except for residual amounts in vessels and pipes (about 550 gallons) that could not be drained. All buildings, the fuel pools cnd facility components have been decontaminated q to remove loose contamination. A protected area has bein established for ' Fermi 1 structures that do not meet Regulatory Guide 1.86 limits for unrestricted ' access (FigureNo,'1). The primary system which has been drained is sealed and is mrintained at a po itive, low pressure with a mixture of nitrogen and carbon duwide. The carbon' dioxide reacts slowly with the rosidual sodium to form an inert solid compound of sodium carbonate. i Other systems and tanks which containcd sodium have been drained. Where y sipr.ificant amounts of residual sodium was present the systems and tanks were j a'.so passivated with carbon dioxide. Two waste water tanks in the Fuel and
. Repair Building (FARB) contain a total of 7550 gallons of water that is slightly contaminated with radionuclides. This water has accumulated over the years from the sump pump system in the FARB. Much of the water tht was pumped into these tanks came from inleakage of rain water from the Health Physics Building. l The Health Physics Builiding has now been removed and its drains to the waste water. sump plugged. l i
2.0 ' EVALUATION 1 In our evaluation we considered residual radionuclides, surveillance and l monitoring, and access control. 2.1 Residual Radionuclides 1 1 Residual-radionuclides at the Fermi 1 site consist of activation products in l the reactor vessel and internals, contamination of surfaces, contamination in residual sodium and contamination of water in tanks. O.r=ok - U.._.._....... . .
l' l* 2.1.1 Activation Products By far the greatest amount of residual radioactivity is the activation products , in the reactor vessel internals and the reactor vessel itself. The licensee ! has calculated that out of the total of 477 curies of radionuclides the reactor l Vessel internals contain about 475 curies of activity and the reactor vessel contains about 2.0 curies of activity. The potential exposures to workers at the present time and at the end of the 40 year SAFSTOR period are based primarily on exposures from Cobalt-60 and Cesium-137. The licensee has calculated the total amount of Cobalt-60 at 275 curies and the amount of Cesium-137 at 11 millicuries. The amounts of these radionuclides 40 years later was calculated to be 1.4 curies and 4.5 millicuries respectively. Therefore, the potential exposure rate for workers will be reduced by more than a factor of 100 in the 40 year SAFSTOR period. Also since nearly all of the residual radioactivity will be in the reactor internals, the removal and disposal of the major radiation source should be much easier than if the major source were in the reactor vessel which may have to be cut up for disposal. 2.1.2 Surface Contamination Surface contamination in buildings and components conrists of Cesium-137, Cobalt-60 and Sodium-22. The licensee surveyed all fermi 1 areas within the protected area (Figure 1). The surveys indicated that removable contamination was within Regulatory Guide 1.86 limits for unrestricted access (1000 dpm/100 cm2) in all areas except for the Delay and Cutup pools in the FARB. Also, general area gamma exposure rates 3 are less than 5 microrem per hour at one meter for reactor generated radionuclides except for:
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(1) The Delay and Cutup Pools, hot drains, waste tanks, Pump Room and sumps all in the FARB; (2) The Primary Sodium Tunnel; (3) The Gas Tunnel; and (4) The Waste Gas Building. In the above aress (1 through 4) gamma radiation in a few spots exceeds our guidance of 5 microrem per hour. Analysis by the licensee has shown, however, that in 40 years most of the above areas will meet the 5 microrem per hour criteria. Therefore a significant reduction in the decontamination effort and the volume of radioactive wt.ste should result from the 40 year delay in decontamination of Fermi 1. 2.1.3 Contamination in Residual Sodium The Radionuclides in the 550 gallons of residual sodium are estimated to be 1.0 millicuries of Sodium-22 and 5 millicuries of Cesium-137. The licensee's calculations show that any accidental release of 100 percent of these radio-nuclides from the residual sodium would result in less than 0.003 millirem whole body exposure at the site boundary. Therefore, we agree that the residual sodium does not present a significant radiological hazard to the health and safety of the public.
l 2.1.4 Waste Water Contamination At the present time 7550 gallons of slightly contaminated water (6 mei each of Cesium-137 and Cobalt-60) is stored in the waste water tanks in the FARB. In its letter dated December 22, 1988 the licensee committed to the removal and processing of 95 percent of this water by May 31, 1989. Following water removal operations two tanks will retain a small amount of water, 400 gallons in the Mark 15 Tank and 200 gallons in the Mark 9 Tank. The licensee itenes to retain 1 this amount of water to assure that level indutors will function and can be j checked for operability. ! The licensee has shown in its analysis that an accidental release of all 7550 gallons of waste water would result in water concentrations at the Monroe city water intake that are about 10 percent of the concentration limits of 10 CFR Part 20, Appendix B Table II for normal operational releases. When the licensee completes its removal of 95 percent of the waste water, the potential offsite exposures from an accidental release would be reduced by a factor of 20. We have therefore determined that the potential exposures from an accidental release of water from the waste water tanks does not result in a significant health and safety risk because of the low concentration of radionuclides), the remote possibility of the tanks rupturing and the licensee's plans for removal of 95 percent of the waste water. 2.2 Surveillance and Monitoring Technical Specifications (TS) requirements have been established for weekly surveillance of the primary system cover gas pressure and for annual testing of the cover gas relief valve. Weekly surveillance of the nitrogen cover gas pressure for the empty sodium tanks has also been established as a TS require-ment. We have determined that this surve11ance is adequate because a temporary loss of pressure of the cover gases will not cause significant water reactions with the residual sodium since the sodium has been mostly passivated at this time and water is not likely to enter the systems because of cover gas pressure loss. The stainless steel primary system is located within the Reactor Building and the empty sodium tanks are located in the Sodium Building Complex (Figure 1). All components containing significant residual sodium are therefore inside buildings and protected from the elements. Any roof leaks or other leakage would be detected during the weekly surveillance and repaired before the primary system or the empty sodium tanks could be significantly damaged. TS requirements have been established for environmental surveillance at locations where the licensee estimated thct maximum concentrations would occur for any radioactive material discharged from the plant. Figure 2 shows location of rmpling. Weekly grab samples are taken from river water and lake water and ann il grab samples from the South Lagoon. These , water samples are analyzed ft beta radioactivity. Sediment samples are taken l in the South Lagoon on a semiannual basis and analyzed for gamma radioactivity. The staff has determined that the proposed environmental surveillance is ; adequate in view of the fixed nature of the residual radioactivity at Farmi 1. l l _ _ - - - - _ _ - - - - - - - - - - - -- a
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4. Quarterly radiation surveillance of the reactor building and the FARB is required by the TS to detect any spread of contamination. The staff has
.. reviewed these surveillance requirements and determined that they are adequate.
2.3 Access Control The primary purpose of access control at Fermi 1 is to assure that unauthorized personnel will not be exposed to hazardous radiation levels. Since there is no fuel at Fermi 1, safeguards / security is not an issue. Access to the reactor internals and reactor vessel, the major source of radio-activity, is prevented by the sealed and shielded reactor structure. Access to other parts of the facility is controlled by locked gates and doors. In addition, security guards control access to the Fermi 1/ Fermi 2 site. The access control is adequate because the only hazardous radiation is in the reactor vessel and its internals which are well isolated. 3.0 FINDING OF NO SIGNIFICANT IMPACT An Environmental Assessment has been prepared as part of this action and is enclosed. A Finding of No Significant Impact was published in the FEDERAL REGISTER on April- 27, 1989. The staff has determined that the proposed action will not have a significant effect on the quality of the human environ-ment. Based on our environmental assessment we have determined that no environ-mental impact statement need be prepared in connection with the issuance of , I. this amendment.
4.0 CONCLUSION
A Notice of Consideration of Issuance of Amendment to facility License and Opportunity for Hearing was published in the FEDERAL REGISTER on November 7, 1985'(50FR46371). No requests for hearing and no public comments were received. The staff has concluded, based on the considerations discussed above, that: (1) there is reasonable assurance that the health and safety of the public will not be endangered by the proposed activities and (2) such activities will be conducted in compliance with the Commission's regulations and the issuance of this amendment will not be inimical to the common defense and security nor the health and safety of the public. Principal Contributor: Peter B. Erickson Dated: April 28, 1989 u
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