NRC-99-0035, Application for Amend to License DPR-9 to Modify TS Section D.3.Amend Would Eliminate TS Surveillance Requirement for Ni Cover Gas on Nearly Empty Primary Sodium Storage Tanks in Sodium Bldg Complex.With marked-up & Typed TS Pages

Application for Amend to License DPR-9 to Modify TS Section D.3.Amend Would Eliminate TS Surveillance Requirement for Ni Cover Gas on Nearly Empty Primary Sodium Storage Tanks in Sodium Bldg Complex.With marked-up & Typed TS Pages

ML20205T528
Person / Time
Site:	Fermi
Issue date:	04/20/1999
From:	Gipson D DETROIT EDISON CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20205T532	List: ML20205T536 NRC-99-0035, Application for Amend to License DPR-9 to Modify TS Section D.3.Amend Would Eliminate TS Surveillance Requirement for Ni Cover Gas on Nearly Empty Primary Sodium Storage Tanks in Sodium Bldg Complex.With marked-up & Typed TS Pages
References
CON-NRC-99-0035, CON-NRC-99-35 NUDOCS 9904270273
Download: ML20205T528 (11)

Text

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./ , Douglas R. Gipson

• • Senior Vice I resident, Nudear Gena ation Fermi 2 6400 North Dixie Hwy., Newport, Allehigan 48166 Tel:734.5A6.5201 Fax:734.586 4172 Detroit Edison April 20,1999 ,

NRC-99-0035 '

U. S. Nuclear Regulatory Commission Attn.: Document Control Desk Washington, D. C. 20555

References:

1) Enrico Fermi Atomic Power Plant, Unit No. I NRC Docket No. 50-16 NRC License Number DPR-9

, 2) NRC Letter, " Issuance of Amendment No. 9 to renew Possession-Only License No. DPR-9 for Fermi, Unit 1",

dated April 28,1989

Subject:

Proposed Technical Specification Change (License Amendment) -

Primary Sodium Storage Tanks Pursuant to 10 CFR 50.90, Detroit Edison hereby proposes to amend Possession Only License No. DPR-9 for the Fermi I plant by modifying Technical Specification Section D.3, Surveillance Requirements.

This application proposes to eliminate the Technical Specification surveillance requirement for nitrogen cover gas on the nearly empty primary sodium storage tanks in the Sodium Building Complex. Deletion of the cover gas is proposed to prepare for the removal of the primary sodium from the storage tanks. This application also addresses opening these tanks as needed for access. The current Fermi 1 Safety Analysis Report (F1SAR) mentions the tanks were welded shut during earlier decommissioning activities.

I The description and evaluation of the changes are included in Enclosure I to this letter.

Enclosure 2 provides the marked up pages of the existing Technical Specification to show i the proposed change and a typed version of the affected Technical Specification with the proposed change incorporated.

Detroit Edison requests that this amendment be approved with an implementation time period of"within 60 days."

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USNRC NRC-99@35 Page 2 -

Detroit Edison has evaluated the proposed Technical Specification change against the criteria of 10 CFR 50.92 and determined that no significant hazards consideration is involved. The Fermi 1 Review Committee has approved the proposed Technical Specification changes and concurs with the enclosed determinations. In accordance with 10 CFR 50.91, Detroit Edison is providing a copy of this letter to the State of Michigan.

If you have any questions, please contact Lynne S. Goodman, Director Fermi 1 at 734-586-1205.

Sincerely, Enclosures (2) cc: NRC Regional Administrator, Region III S.W. Brown S. Campbell P. Lee, NRC Region III D. Minaar(State of Michigan) i l

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, USNRC NRC-99-0035 Page 3 j I, DOUGLAS R. GIPSON, do hereby afrum that the foregoing statements are based on i facts and circumstances which are true and accurate to the best of my knowledge and belief.

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DOUGLAS R. GIPSON Senior Vice President 1 On this A day of dIb ,1999 before me personally appeared Douglas R. Gipcon, being first duly sworn and says that he executed the foregoing as his free act and deed.

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Sudi $taa72 NotaryPublic l i

l ROSALIE A. ARMETTA NOTARYPUBUC MONROECOUNTY,Mt MYCOMMIS$10N EXPIRES 10d1/99 l

USNRC NRC-99-0035 Page 4 bc: G. Cerullo P. Fessler D.R. Gipson L.S. Goodman P. Marquardt J.E. Conen L. Craine J. Couillard ,

R.R. Eberhardt, Jr.

D. Ferencz W.D. Gilbert J R.A. Janssens E.F. Kokosky R. Laubenstein E.F. Madsen R.H. McLenon J.E. Meyers B. Michelbacher W. O'Connor, Jr.

E.M Wilds D.R. Williams Information Management (116 NOC) - Fermi 1 Records NRR Chron File (Licensing) i i

NRC Notebook (Fenni 1) 1 l

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1, - .

Enclosure !

NRC-99-0035 Page!

ENCLOSURE 1 DESCRIPTION AND EVALUATION OF PROPOSED TECHNICAL SPECIFICATION CHANGE Enrico Fermi Atomic Power Plant, Unit 1 NRC Docket No. 50-16 4 NRC License No. DPR-9

Enclosure 1 NRC-99-0035 Page 2 DESCRIPTION DE PROPOSED CHANGE The purpose of this proposed amendment is to modify the Technical Specifications to delete the requirement for surveillance of the nitrogen cover gas pressure over the nearly empty primary sodium storage tanu in the Sodium Building complex. The revision to the specific article is described as follows:

Section D.3.c is being revised to delete the requirement to check the nitrogen cover gas pressure aver the three primary sodium (Na) storage tanks in the Sodium Building complex. Section D.3.c of the Technical Specifications states: " Observations of the nitrogen cover gas pressure over essentially empty sodium storage tanks in the Sodium Building Complex shall be performed

- weekly".

Since the requirement to check the pressure over the sodium storage tanks is being deleted, the title of Section D is revised to delete " Storage Tank" from the section title. Other subsections in -

Section D are for the primary system cover gas. The revised title will be " Primary System Cover Gas".

- Also, this amendment request evaluates opening up the sealed primary Na storage tanks to allow access. The Fenni 1 Safety Analysis mentions that the tanks were welded shut in the description of previous decommissioning activities.

During the decommissioning of Fermi 1, the primary Na was drained into the three 15,000-gallon storage tanks and 55-gallon steel drums from four major systems: the primary system, the service system, the transfer tank, and the FARB service system. Only 45,000 gallons of the total estimated inventory ofprimary sodium, about 77,000 gallons, was stored in the storage tanks. In 1983, the contents of the primary Na storage tanks were drained and placed in 55-gallon steel drums. The drums were shipped to Argonne National Laboratory - West in Idaho in 1984. The

. sodium residue in the tanks was then passivated with a carbon dioxide (CO2 ) cover gas. The tank openings were welded shut and the tanks sealed in the shielded storage room by locking the \

access door. Carbon dioxide was used because it would react slowly with residual metallic sodium, fonning sodium carbonate. The use ofcarbon dioxide also prevented moisture from the air from reacting with sodium and releasing hydrogen gas. Later, the CO2 was replaced with a nitrogen (N 2) cover gas.

Currently, the N 2gas pressure is normally maintained between 1 psig and 5 psig. There is expected to be a combined total of approximately 50 gallons of residual Na remaining in the three primary Na storage tanks.

The N, gas is contained in an isolated bottle connected to pipes leading to the three storage tanks.

. The weekly surveillance involves checking the three storage tank pressure gauges. When the

. pressure falls outside the surveillance limits, N2is manually added to the storage tanks to maintain the pressure.

t Enclosure 1-NRC-99-0035

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l Approval of this proposed amendment will allow the cover gas to be maintained, discontinued, or changed, and pennit opening of these tanks for access. This will provide Detroit Edison more  ;

flexibility to support project activities leading to cleanup of the residual primary sodium. This proposed amendment is evaluated as if the cover gas will be discontinued afler the amendment is

- approved.

I EVALUATION OF THE PROPOSED CHANGE l The purpose of this evaluation is to consider the consequence of deleting the Technical Specification requirement for observing the cover gas pressure on the primary Na storage tanks in preparation for removal of the primary Na in the future. Also, the evaluation addresses opening up the primary Na storage tanks for future work activities.

The NRC reviewed and approved the Technical Specification requirement to A forN2 cover gas pressure on the " essentially empty" Na tanks through the issuance of Amen it No. 9, April 28,1989 (Reference 2). The NRC Safety Evaluation states that a temporary loss ofcover gas pressure will not cause "significant water reactions" with the residual sodium since the tanks were passivated with CO 2and water is not likely to enter the tanks because of cover gas pressure loss.

The Technical Specifications do not specifically require the N2cover gas system to be continuously in service. The only requirement is to observe the pressure weekly. Action is required should the N2 cover gas pressure not meet proceduralized criteria. Also, the Technical Specifications do not otherwise address the primary Na storage tanks status, except that they are essentially empty.

Deletion of the N 2cover gas system may bejustified by the following examples:

1. During the dec0mmissioning of Fermi 1, the secondary Na storage tanks located in the basement of the Steam Generator Building were purged with 7-8 psig CO2 to passivate the residual Na and sealed closed. The atmosphere inside one of the tanks was sampled and analyzed in 1997 and the results showed a 10% by volume concentration of CO2 . The other sample constituents by volume were 0.04% hydrogen,13% oxygen,78% nitrogen,0.2%

argon, and < 0.05% carbon monoxide. A visual inspection inside the secondary tanks showed a white layer of sodium carbonate on the pipe and valve flange on the top of the tank.

The bcttom of the tank was a dull metallic gray, revealing approximately 34 to 70 gallons of solid residual Na, a total of 200 gallons or less in the three secondary Na storage tanks combined. These storage tanks have remained in this condition for over 20 years. l The Techr.ical Specifications characterize the primary Na storage tanks as " essentially  !

empty". The quantity ofprimary Na in each storage tank is expected to be less than the ,

quantity of secondary Na in each storage tank. The condition of the Na in the secondary j tanks showed that the absence of a cover gas system did not result in any adverse consequences. l l

. Enclosure 1 -

NRC-99-0035 Page 4 The secondary Na storage tanks have been breached for inspection, monitoring, and other work activities on occasions during the past two years. No adverse effects have been noted.

No adverse consequences will be expected if the primary Na storage tanks are similarly opened for work activities.

2. A comparison between the condition of the primary storage tanks and the secondary storage tanks supports approval of this change. The secondary Na storage tanks are in a relatively moist atmosphere. Surface corrosion was revealed on the tanks when the asbestos was removed in 1997. An informational ultrasonic examination performed on two of the secondary tanks showed no decrease in thickness from the original norninal tank shell thickness, indicating no loss from corrosion. The primary Na storage tanks are housed in the Sodium Building which has a dryer atmosphere. The primary Na storage tank surfaces exhibited little corrosion under a thin coat of paint when the asbestos was removed in 1998.

The nominal tank shell thickness for both primary and secondary Na storage tanks was 3/8 -

inch.

Since the primary Na storage tanks appear to be in good condition and were exposed to a less corrosive atmosphere, their condition should be at least as good as the secondary Na storage tanks. Since the secondary Na storage tanks have contained the residual Na without a cover gas pressure system for over 20 years, the primary Na storage tanks are capable of storing sodium safely without a cover gas system.

3. Any potential release of the estimated 50 gallons of residual Na remaining in the primary storage tanks as a result of removing the primary cover gas system is bounded by the Na accident evaluation in the Fermi 1 Safety Analysis Report. A postulated radiological accident covers an airborne release of all primary residual Na including the entire radionuclide inventory of the Na which was estimated to contain a total of 0.98 mci 22Na, 4.84 mci '"Cs, and 70 mci'H. In the event of a fire or other catastrophic event, the release i of residual sodium results in concentration levels well below the values in 10 CFR 20, Appendix B, Table II, for releases to unrestricted areas.

If opening the tanks resulted in releasing the residual sodium, the potential radiological release is the same as addressed above.

Removing the surveillance requirement for the N2 cover gas will enable Detroit Edison to make preparations for cleanup of the primary storage tanks which will eliminate the residual Na and any need for a cover gas over the tanks in the future. Opening the tanks will also facilitate cleanup preparations.

The change in the title for Section D of the Technical Specifications is an editorial change, since the remaining section requirements apply only to the primary system cover gas.

.- . . Enclosure 1

' NRC-99-0035

-Page5 SIGNIFICANT HAZARDS CONSIDERATION In accordance with 10 CFR 50.92, Detroit Edison has made a determination that the proposed amendment involves no significant hazards considerations. To make this determination, Detroit

Edison must establish that conduct of activities in accordance with the proposed amendment would not: (1) involve a significant increase in the probability or consequences of an accident previously evaluated, or (2) create the possibility of a new or different kind of accident from any accident previously evaluated, or (3) involve a significant reduction in a margin of safety.

1. The proposed change does not involve a significant increase in the probability or consequences of an accident.

Removing the primary cover gas supply from the storage tanks will not significantly increase '

the probability of an accident occurring as long as the probability of an uncontrolled water reaction with residual sodium is not significantly increased. This is ensured by sealing the storage tnnks after the nitrogen cover gas system is removed except when controlled activities such as sampling are performed. The consequences of an accident would not be i affected by removing the N 2cover gas supply from service as the previously analyzed primary Na accident already involves release of all the radioactive material in the primary Na. Removing the cover gas will not increase the amount of radioactive material available to be released.

2. The proposed change does not create the possibility of a new or different accident from any previously evaluated.

i A sodium accident has been previously evaluated. No other type of accident could be caused  !

by removing the primary sodium storage tanks cover gas or opening the tanks since no other system or mode of operation of any other system will be affected. I

3. The proposed change does not involve a significant reduction in a margin of safety, i Only a small amount of sodium remains in the primary sodium storage tanks. Some of this residual may have been converted to sodium carbonate, leaving even less sodium remaining.

The cover gas is a good precaution, especially for tanks sitting unattended for many years. It prevents moisture from intruding into the tanks and reacting with the sodium residues. It prevents oxygen from entering and reacting'with any hydrogen formed from reactions of j water with sodium. Discontinuing the use of cover gas slightly reduces the margin of safety, J but not significantly. Removing the cover gas does not, in itself, introduce water into the tank in an uncontrolled manner. Even if slight amounts of moisture from humidity in the air enter over the next year or two until the sodium is removed while the tank is opened or scaled, the tank volume (15,000 gallons) is large enough that the tank should be able to dissipate any small reactions that occur. The design pressure for the primary Na storage tanks is vacuum to 50 psi per the vendor drawing.

-. Enclosure 1

. ' NRC-99-0035 Page 6 Even if sufficient water entered the tank, generated hydrogen, and sufficient oxygen entered the tank to cause a reaction that released the contents of the tank, there would be no significant release of radioactivity from the tank. The release of all residual primary sodium would result in concentration levels well below the values in 10 CFR 20, Appendix B, Table II for releases to unrestricted areas. Since there is less sodium in the primary Na j storage tanks than in the secondary Na storage tanks, potential chemical hazard consequences of releasing the contents of a primary Na storage tank are bounded by the hypothetical secondary sodium scenario evaluated in the Fermi 1 Safety Analysis Report. For these reasons, the proposed change does not involve a significant reduction in the margin of safety.

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ENVIRONMENTAL IMPACT Detroit Edison has reviewed the proposed Technical Specification changes against the criteria of 10 CFR 51.22 for environmental considerations. The proposed changes do not involve a significant hazards consideration, nor significantly change the types or increase the amounts of effluents that may be released offsite, nor increase individual or cumulative occupational radiation exposures. Based on the foregoing, Detroit Edison concludes that the pmposed Technical Specifications meet the criteria given in 10 CFR 51.22(c)(9) for a categorical exclusion from the requirements for an Environmental Impact Statement. I CONCLUSION Based on the evaluations above: (1) there is reasonable assurance that the health and safety of the public will not be endangered by conduct of activities in the proposed manner, and (2) such activities will be conducted in compliance with the Commission's regulations, and the proposed amendment will not be inimical to the common defense and security or the health and safety of the public.

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1 Detroit Edison requests that the proposed license amendment be effective within 60 days of j

approval by the Commission. j

Enclosure 2 NRC-99@35 Page1 ENCLOSURE 2 PROPOSED i TECHNICAL SPECIFICATION CHANGE Marked-up TechrA~al Specification (2 Pages)

Typed Revised Technical Specification (2 Pages)

Enrico Fermi Atomic Power Plant, Unit 1 NRC Docket No. 50-16 NRC License No. DPR-9