ML20217N438

Safety Evaluation Supporting Amend 17 to License DPR-9

ML20217N438
Person / Time
Site:	Fermi
Issue date:	10/25/1999
From:	NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS)
To:
Shared Package
ML20217N429	List: ML20217N426 ML20217N430 ML20217N438 ML20217N449
References
NUDOCS 9910290030
Download: ML20217N438 (4)

Text

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. SAFETY EVALUATION BY OFFICE OF NUCLEAR MATERIAL SAFETY AND SAFEGUARDS i RELATED TO AMENDMENT NO.17 TO FACILITY OPERATING LICENSE NO. DPR-9 DETROIT EDISON COMPANY ENRICO FERMI ATOMIC POWER PLANT. UNIT 1 POCKET NO. 50-16

1.0 INTRODUCTION

By letter dated April 20,1999, the Detroit Edison Company (DECO or the licensee) submitted a request for a change to the Enrico Fermi Atomic Power Plant Unit 1 (Fermi 1 or the facility)

Technical Specifications (TS) appended to Facility Operating License No. DPR-9. The requested changes were: (1) deletion of surveillance requirement D.3.c, which requires weekly observation of the nitrogen cover gas pressure within the sodium storage tanks located in the sodium building; and (2) revise the title of Specification D.

2.0 EVALUATION During an earlier phase of the Fermi 1 decommissioning process, the licensee drained the primary sodium from the following: the primary system, the service system, the transfer tank, and the Fuel and Repair Building (FARB) service system. The licensee placed this sodium into three 15,000-gallon storage tanks and 55-gallon steel dmm.;. In 1983 the contents of the primary sodium storage tanks were drained and placed in 55-gallon steel drums. In 1984 these drums were shipped to the Argonne National Laboratory located in Idaho. The licensee then welded the tank openings shut. The licensee then tried to passivate the residual sodium residue left in the tanks with a carbon dioxide cover gas. Carbon dioxide gas was used because it would react slowly with the residual metallic sodium to form sodium carbonate. This cover gas would also prevent moisture contained in the air from entering these systems and reacting with the sodium.  !

This reaction would release hydri pn gas. The licensee later changed the cover gas in the l primary sodium storage tanks from carbon dioxide to nitrogen. The licensee still uses carbon l dioxide as the primary system cover gas. {

l The licensee is in the process of performing industrial remediation at the Fermi I site. Included in this industrial remediation is the removal of the remaining residual sodium from piping systems and tanks. To remove the sodium from the primary storage tanks the licensee will need 9910290030 991025 PDR ADOCK 05000016 P PDR ,

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to make openings in these tanks, an action that may make maintaining a cover gas in these tanks impractical. Thus, the licensee has requested the deletion of surveillance requirement D.3.c.

This surveillance requirement states that "[0]bservations of the nitrogen cover gas pressure over essentially empty sodium storage tanks in the Sodium Building Complex shall be performed weekly." When the licensee finds the pressure reading below the surveillance limits, nitrogen is m2 ually added to the storage tanks.

The licensee stated that no longer maintaining the cover gas for these storage tanks would not adversely impact the public health or safety based on the following:

1. When the licensee began similar preparatory work to remediate the secondary sodium storage tanks, the licensee found approximately 30 to 70 gallons of non-passivated residual sodium in the bottoms of the three tanks. The licensee noted that this approximately 200 gallons of non-passivated residual sodium has remained in a stable condition for more than 20 years without a cover ga system. In addition, the licensee noted that over the past two years this non-passivated residual sodium has remained in a stable condition while the secondary sodium storage tanks have been breached for inspections, monitoring, and other work activities in preparations to remove this sodium. The licensee expects that there will be less residual sodium, approximately 50 gallons, in the primary sodium storage tanks.

Additionally, the licensee determined that the area where the secondary sodium storage tanks are located the atmosphere contains more moisture than the area where the primary sodium storage tanks are located. The licensee concluded this based on the exterior condition of the secondary sodium storage tanks versus exterior condition of the primary sodium storage tanks. The licensee notes based on the experience obtained from the secondary sodium storage tanks, it does not expect any adverse consequences from removing the nitrogen cover j gas from the primary sodium storage tanks, and to breach these tanks to begin to perform similar preparatory work as was done for the secondary sodium storage tanks.

2. The licensee noted that it had previously analyzed the impact of an unlikely catastrophic event that would result in the release to the environment of the total estimated radionuclides inventory contained in all of the residual sodium in the primary system. This accident scenario was presented in Section 8.4 of the Fermi 1 Safety Analysis Report. The results of the licensee analysis indicated that if such an unlikely event were to occur an adult member of the public would receive a total body dose of 0.0013 mrem and a dose to the liver, the most critical organ, of 0.0015 mrem. Thus, the dose that results from this unlikely event is  !

insignificant when compared to the 10 CFR Part 20 dose limit for an individual member of i the public from an operational facility of 100 mrem per year. )

I NRC staff finds the licensee's proposal acceptable based on: (1) the licensee's experience acquired from similar conditions from the work being performed to remove the residual sodium from the secondary sodium storage tanks, and (2) tue results of the licensee's analysis which demonstrated that should an unlikely event occur the dose to a member of the public would be

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insignifict.nt when compared to the Part 20 limit for an individual member of the public from an operational facility.

Also, the licensee has requested that the title of Specification D,"PPlMARY SYSTEMS \ STORAGE TANK COVER GAS" be revise by deleting "S\ STORAGE TANK "

This change would reflect deletion of surveillance requirement D.3.c. The NRC staff finds this requested change acceptable because it is considered an editorial change.

3.0 STATE CONSULTATION

In accordance with the NRC regulations, a Michigan State official was notified of the proposed issuance of the amendment. The State official had no comments.

4.0 ENVIRONMENTAL CONSIDERATION

This amendment deletes the requirement for the licensee to maintain a nitrogen cover gas within the sodium storage tanks located in the sodium building. NRC staff has previously issued on ,

August 11,1999, a proposed finding that the amendment involves no significant hazards consideration (64 ER 43770), and there has been no public comment on such finding. Further, NRC staff has determined that the amendment involves no significant change in the types or significant increase in the amounts of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure.

Accordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9). Pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendment.

5.0 CONCLUSION

The NRC 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 operation ]

in the proposed manner; (2) such activities will be conducted in compliance with the NRC j regulations; and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.

Principal Contributor: Stewart W. Brown, DWM/NMSS

.. .. i Date: October . 25 ,1999 i

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ENCLOSURE 1