ML20126G148

Responds to NRC 921214 Request for Addl Info Re Util 920928 Request for Full Exemption from 10CFR50.54(w) on Property Insurance.Util Reiterates That 10CFR50.54(w) Inapplicable Based on Defueled Condition of Plant

ML20126G148
Person / Time
Site:	Yankee Rowe
Issue date:	12/30/1992
From:	Mellor R YANKEE ATOMIC ELECTRIC CO.
To:	Fairtile M NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation
References
BYR-92-114, TAC-M84579, NUDOCS 9301040086
Download: ML20126G148 (6)

Text

- --

. YANKEE ATOMIC ELECTRIC COMPANY ""C";,1.laZ'";"l" e-  ;,

L5 580 hiain Street, Bolton, hiassachusuts 01740-1398 (x,YANREE

-- -* December 30, 1992 BYR 92-114 United States Nuclear Regulatory Commission Document Control Desk Wachington, DC 20555 Attention: Mr. Morton Fairtile Senior Project Manager Non-Power Reactors and Decommissioning Project Directorate Division of Operating Reactor Support

References:

(a) License No. DPR-3 (Docket No. 50-29)

(b) Letter, H. Tracy, Yankee Atomic Electric Company (YAEC) to M. Fairtile, U. S. Nuclear Regulatory Commission (NRC), dated September 28, 1992 (c) Letter, M. Fairtile, NRC to J. Grant, YAEC Company, dated December 14, 1992

Subject:

RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING PROPERTY INSURANCE EXEMPTION REQUEST (TAC NO. M84579)

Dear Mr. Fairtile:

In Reference (b), Yankee Atomic Electric Company (YAEC) requested f rom NRC a full exemption to 10 CFR 50.54 (w) regarding property insurance for the Yankee Nuclear Power Staticn (YNPS). Reference (c) transmitted an NRC request for additional information regarding YAEC's exemption request. Response to the specific Staff request is attached.

We wish also to take this opportunity to emphasize that in our initial submittal, we clearly identified that 10 CFR 50.54 (w) no longer applies to YNPS. We believe that the basis for our request deserves repeating here.

10 CFR Section 50.54 (w) (2) (1) defines " accident" as "an event that involves the release of radioactive material from its intended place of confinement within the reactor or on the reactor station site such that there is a nresent danger of release off site in amounts that would pose a threat to the public health and safety." (Emphasis added.) NUREG/CR-2601,

" Technology, Safety, and Costs of Decommissioning Reference Light-Water Reactors Following Postulated Accidents," identifies the kind of accidents that. meet the 10 CFR definition. j i 9301040086 921230 -

1 POR ADOCK 05000029 It\

J PDR -

Ur.ited s mtes Nuclear Regulatory Commission Page 2 BYR 92-114 Accidents as defined by 50.54 (w) (2) (i) and as identified by NUREG/CR-2601 can no longer occur at YNPS. With YNPS in a permanently shutdown and defueled condition, the only postulated design basis event that can potentially occur is a fuel handling accident. A fuel handling accident at YNPS cannot lead to the release of radioactive materials such that the public health and safety would be threatened. The radiological consequences of such an accident have been previously provided to the NRC for review. NRC has verifled the results and accepted the fuel handling accident as the basis for both the Defueled Emergency Plan and Defueled Security Plan.

In summary, 10 CFR 50. 54 (w) no longer applies to YNPS because there is no design baals accident that could result in a threat to the radiological health and safety of the public. However, as indicated in Reference (b), it is prudent for YAEC to continue to insure YNPS for property damage risks in order to protect its ratepayers and stockholders. YAEC does not consider maintenance of such coverage as a regulatory requirement.

If you should have any questions concerning the attached response to the Request for Additional Information or the position reiterated above, please feel free to cell Jane Grant or me at 508-779-6711.

Sincerely, YANKEE ATOMTC FLECTRIC COMPANY l i S. . e /

Russell A. Mello Project Manager Yankee Rowe Project e: NRC Region I NRC Resident Inspector (Rowe)

R. Dudley, NRC, NRR e

+

t l

Allachmrol Remtut for AthlithmaLhtrnrnm Inn Provide a description of all sources of stored radioactive fluids at the plant site.

Demonstrate either the integrity of the storage method or if the fluids were to escape ,

from the storage vessel, show that the proposed property insurance coverage would be adequate to cover recovery costs. in the demonstration of integrity, consider component or system failures and/or operator errors.

Enum1&c The following is a description of the sources of stored radioactive fluid on site along with the design and operating features to preclude and control release of the fluid to the environment.

Wnstt_[hthbuutnd Attivity DRitthatJ)tfALTn.rtks ,

The waste holdup tank and activity dilution decay tank, each with a capacity of 75,000 ,

gallons, are located adjacent to each other within a 10-foot tall reinforced concrete enclosure designed to contain the contents of both tanks in the unlikely event of a tank rupture. Each tank is constructed of stainless steel.

During plant operation these tanks were used to process hydrogenated radioactive liquid originating primarily from reactor coolant letdown and leakage from reactor coolant auxiliary systems. During plant operation the tanks were vented to the waste gas system which operated to collect and process fission gases and hydrogen. In the current mode of plant operation, the waste gas system has been purged and vented and the tanks are used to store aerated radioactive liquid prior to processing through the liquid radwaste evaporator.

At this time, the reactor coolant system (except the reactor vessel) and most of the reactor auxiliary systems have been drained, and the liquid processed through the radwaste evaporator. As a result, the volume of water stored in the tanks at any given time is minimal. Ilowever, YAEC currently plans to maintain the existing liquid radwaste systems operational to support current plant operation and future decommissioning activities.

Based on the above, the unlikely failure of the waste holdup or activity dilution decay tanks does not represent a significant liability, since the entire tank contents will be  ;

contained within the reinforced concrete dike surrounding each tank. Such confinement simplifies decontamination and cleanup.

Page 1 I

M { @ 7d W s M M b I 1

I' Atladimtnt (coni,)

51akty injtcilen Timli During normal plant operatioa, the Safety injection Tank (SIT) contained more than 125,000 gallons of borated, slightly contaminated water. The tank contents were used to fill the refueling cavity during refueling operations, and to provide the suction source for the Emergency Core Cooling System.

The SIT, erected in 1990, is located outside to the west of the waste disposal building, and is constructed of stainless steel with overnow directed to the waste disposal building sump. The tank was designed and built to YNPS seismic design criteria. Since cessation of power operation, the SIT has been drained and the Guld has been processed through the radwaste evaporator.

Currently there are no plans to use the SIT to store radioactive water. The refueling cavity can be filled via other systems, and the cavity can be drained to the waste holdup and activity decay tanks described above, llowever, the SIT will be maintained as a potential storage location for radioactive Guid. Use of the tank will be minimized, and any stored fluids will be processed or transferred in a timely manner. The combination of minimal activity concentrations, limited fluid storage time, design and construction features and the service life of the tank and connected piping, make the probability of discharge of significant radioactivity to the surrounding area, exceedingly small. In addition to the low probability of tank failure, the radioactive water contained in the SIT was typically within 10 CFR 20 Appendix 13 limits thus limiting the radiological impact of any tank leakage.

YAEC has estimated the costs associated with onsite decontamination and cleanup in the unlikely event that tank leakage should occur. Given the age, design criteria and operating cond;tions of the tank, catastrophic tank failure is not considered a credible event. Instead, the evaluation considered leakage, at a moderate rate, from one of the tank nonle connections, it was assumed that the leakage would cause the surrounding yard area to be contaminated such that remediation would be required. Site cleanup costs were then conservatively estimated and included labor for asphalt and soil excavation, and ultimate disposal of contaminated material at a licensed burial site. No equipment replacement costs were included in the estimate. The total cleanup cost following a safety injection tank leak was estimated to be less than $3 million.

Page 2

i l

- AtlattunculjnstJ Lint!kilitittItalanks Two liquid waste test tanks, each with a capacity of approximately 8000 gallons, are used to collect, recirculate and sample evaporator distillate prior to discharge to the circulating and service water system. The test tanks are located outside and adjacent to the waste disposal building. liach tank is fitted with a rubber liner to minimi7e potential for leakage. Leakage from these tanks would result in spillage of distillate to the surrounding yard area. Typically, the radionuclide concentrations in the distillate are within 10 CFR 20 Appendix 11 limits. The cleanup costs resulting from distillate test tank leakage would be minimal, and bounded by the safety injection tank leakage cleanup costs.

AlonitqtEl Wasie_ Taqk3 Two monitored waste tanks, each with a capacity of approximately 1300 gallons, were designed to store mildly contaminated water from various sources for sampling prior to discharge. These tanks are not in use, and there are no plans to use them to store radioactive fluid in the future.

DihtLMISSclhinsgutTanh3 The plant contains several other miscellaneous radioactive liquid storage and sump tanks which are located inside plant buildings. Any fluid discharged as a result of failure of any of these tanks would be contained within the building. Cleanup cost associated with such leaks will be minimal, and well within the proposed property insurance coverage.

EntnLEurLl'il The Spent Fuel Pit (SFP) at YNPS is a stainless steel lined reinforced concrete structure.

The foundation is a 3 foot thick mat approximately 17 feet below grade. The walls vary in thickness and are doubly reinforced. The SFP has been analyzed for maxiirum dead weight, hydrostatie, thermal and NRC spectrum seismic loadings. Tbe SFP water level is contir.dously monitored with indicatien and alarm in the control room. The most likely source of SFP leakage is from the SFP cooling piping. Limited leakage from this piping will be detected and isolated by the plant operators prior to discharge of a significant volume of water. Cleanup costs associated with this event would be bounded by the SlT leakage cleanup costs.

l l

l Page 3 a T It i

AllMhtutaikut!!J knXuhnnutMt The ion exchange pit is a reinforced concrete structure adjoining the east side of the primary auxiliary building and the south side of the SFP. Its primary function is to house ion cubangers used to purify SFP water. The pit is filled with demineralized water which provides radiation shielding. Water level is monitored locally by the plant operators every shift. All piping penetrations are above the pit operating water level. Any minor leakage from the ion exchange pit would be detected by the cperators prior to discharge of significant volumes of water Cleanup costs associated with this event would be bounded by the SIT leakage cleanup costs.

Lign)d ItatlEnittPip10g 1.iquid Radwaste process piping is routed both inside and outside of plant structures.

Leakage from piping within the buildings would be contained within building sumps, and detected by installed sump alarms or by plant operators. Buried radwaste piping is routed within guard pipes to provide an additional barrier against leakage. The largest storage tanks, which are the activity dilution and waste holdup, are located adjacent to the waste disposal building thus minimizing the length of process piping between the -

tanks and the processing equipment. The probability of process piping leakage going undetected, resulting in significant discharge of fluid is minimal. Any such leakage will be detected and isolated thus minimizing potential cleanup costs. Cleanup costs associated with piping leakage would be bounded by the safety injection tank leakage cleanup costs.

Operator Errors 1.iquid radwaste processing systems are operated by qualified operators in accordance with approved plant operating procedures. The evaporator is operated in a batch mode, and distillate is sampled and analyzed prior to discharge. In addition, the distillate effluent piping is continuously monitored by an inline radiation monitor with an alarm in the control room. Multiple operator errors and procedure violations are necessary to discharge any radioactive liquid directly to the environment prior to processing and/or monitoring. Therefore, the probability of discharge of a significant volume of radioactive fluid as a result of operator error is negligible.

Page 4

>