CY-98-062, Updates Info of Historical Nature in Response to Both NRC Historical Review Rept & NRC Insp Rept 50-213/97-11 Open Items

Updates Info of Historical Nature in Response to Both NRC Historical Review Rept & NRC Insp Rept 50-213/97-11 Open Items

ML20155D120
Person / Time
Site:	Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png
Issue date:	10/28/1998
From:	Mellor R CONNECTICUT YANKEE ATOMIC POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
50-213-97-11, CY-98-062, CY-98-62, NUDOCS 9811030118
Download: ML20155D120 (5)

Text

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YANKEE ATO MIC POWER COMPANY C CONNECTICUT HADDAM NECK PLANT 362 INJUN HOLLOW ROAD e EAST HAMPTON. CT 06424-3099 October 28,1998 Docket No. 50-213 CY-98-062 Re: 10CFR20,2002 U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555 Haddam Neck Plant Update on Historical Information This letter updates information of a historical nature in response to both the NRC Historical Review Report

• and NRC Inspection Report 97-11* open items. This information pertains to the disposal of dredging spoils onsite in the owner controlled area which occurred in 1.979 and 1987.

Summary There is an area outside the radiological controlled area, on owner controlled property, which contains material dredged from the discharge canal in the period between 1979 and 1987. According to the samples taken and analyzed, the dredged material contained trace concentrations of radioactive material. The pile occtgies an area of about 11,200 square i meters.

I Our review of the circumstances of these dredging activities determined that Connecticut Yankee Atomic Power Company (CYAPCO) was required to obtain NRC approval for onsite disposal of licensed material for the dredging which occurred in 1987. A review of our records determined the application had not been filed. NRC regulations did not require NRC approval for the 1979 disposal. b

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"' USNRC Letter to CYAPCO, A. Randolph Blough to Russell A. Mellor, "NRC IIistorical Review Team Report - Radiological Control and Area Contamination Issues at Iladdam Neck," dated hlarch 26.1998.

"'USNRC Letter to CYAPCO, J. R. White to T. C. Feigenbaum, NRC Inspection No. 50-213/ 97-11, dated December 29,1997 (URI 50-213/97-11-0I).

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9811030118 981028 PDR ADOCK 05000213.

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U. S. Nuclear Regulatory Commission l CY-98-062/Page 2 CYAPCO did receive dredging approval permits issued by the U.S. Army Corps of

, . Engineer's (Permit Nos.79-416 and 87-5024) and by the Commissioner of Environmental 4

Protection, State of Connecticut (Water Quality Certification, dated November 21,1979 and Permit No.109, January 15,1987) for the past dredgings.

4 As a result of this review, a dose assessment of the deposited material was performed using NRC approved dose modeling methodology. The results of this assessment show that the estimated dose to the public is less than 1 millirem per year. Similar to 10CFR20.2002 applications, this assessment will be placed in the Updated Final Safety Analysis Report (UFSAR).

Background

l Canal dredging was necessary in 1979 and in 1987. The more recent dredging was necessary to support the 1987 LP Turbine Replacement project. Plans began in 1986 and j included (1) preparing and submitting the necessary permit requests to the Connecticut Department of Environmental Protection, Town of Haddam, and U.S. Army Corps of Engineers, and (2) taking sediment samples for both non-radiological and radiological assessments.

- CYAPCO performed an initial radiological assessment of the dredged material in 1986 and determined that onsite disposal was acceptable based on the following considerations (sampling included 1979 sediment):

1. The material would remain onsite. It was just being moved from one location to another.

I The sludge removed from the canal was deposited on a peninsula between the canal and the Connecticut River, an area within the Haddam Neck Plant controlled area.

Although accessible to the public by way of the river, access is limited and the area is ,

patrolled by the security staff. Release of the material from the site would not be permitted without a further review.

2. Unconditional release of the detectable radioactivity had already been accounted for via a permitted release.

The measured concentrations of radioactivity in sludge samples taken before removal were found to be a factor of one hundred less than the concentrations allowed in liquid effluents. Furthermore, it was believed that the samples did not show an activity concentration of concern. The activity in this sludge resulted from liquid waste discharges that were allowed by 10CFR.

l U. S. N iclear Regulatory Commission CY-98-062/Page 3

3. No inc case in background radiation (dose rate) was expected.

l This expectation was verified by conducting high pressure ion chamber radiation measurements above the deposit area before and after the dredged material was deposited. The results of the high pressure ion chamber radiation measurements were lower following placement of the dredged material. This confirmed that the relocation of the contaminated materials did not cause an increase in background radiation.

Determinatign Based on the above assessment,it was believed an application in accordance with 10CFR20.302 (now 20.2002) was not necessary. In hindsight, an application should have been filed based on review of industry applications setting precedence as well as regulatory guidance provided in Information Notice 83-05," Obtaining Approval for .

Disposing of Very-Low-Level Radioactive Waste - 10 CFR Section 20.302", and NUREG-1101,"Onsite Disposal of Radioactive Waste."

l Discussion It is believed that submittal of a 10CFR20.2002 application at this time is unnecessary l due to the time duration since disposition of the material and the current decommissioning status of the plant. Howevei, a recent dose assessment of the dredging material has been completed and was performed in the same manner as would be appropriate to support an application.

The assessment was performed by modeling the potential dose pathways using the RESRAD version 5.70 computer code. Both the 1979 material and 1986 material were modeled. Because the material is otored on owner controlled land, there are no residents in proximity to the material. The considered dose pathways include external gamma radiation, inhalation of suspended radioactive material, and ingestion of aquatic foot,,

and drinking water. These analyses use conservative estimates for occupancy and access to this material by members of the public.

Table 1-1 and 1-2 summarize the results of the assessment. Table 1-1 presents a summary of the calculated total dose rates, based on the applicable assumptions at the following points in time: 1986 which was time zero for the calculation, 1987,1998,and 2001. (Note: 1986 was chosen as time zero since this was when the radiological l characterization was performed). Table 1-2 presents a summary of the total dose by pathway in 1998.

l As shown in Table 1-1, the maximum total dose from all dredged materials occurred in 1986. Also, from the assessment performed, it is expected that the annual dose from the 1979 material in the time period between 1979 and 1986 would not have exceeded the estimated dose in 1986 because of the similarity in the activity concentrations of the two materials and the lesser volume of the 1979 material.

U. S. Nuclear Regulatory Commission CY-98-062/Page 4 l

Table 1-2 shows that the dose in 1998 from the inhalation, aquatic foods, and drinking water pathways is a small fraction of the total dose, and that a total estimated dose of 0.22 millirem / year is almost entirely attributable to external gamma radiation. (Note: Cs-137 is the major contributor to the external dose pathway. Background subtraction was not performed and the model assumes that all Cs-137 is attributed to CYAPCO.)  ;

Table 1-1 Summary of Total Dose Rate from Models of River Sediment Stored on the Peninsula at Connecticut Yankee

' Time (t) Since 1986--+ t = 0 years t = 1 year t = 12 years t= 15 years (1986) (1987) (1998) (2001)

Total Effective Dose Equivalent Rate (mrem /yr)

Model #1 - 79 in herm* 2.29E-7 2.00E-7 4.73E-8 3.27E-8 Model #2 - 86 in berm 3.16E.1 2.68E-l 1.30E-l 1.17E-l Model #3 - 79 out berm

• 2.72E-1 2.39E- 1 9.03 E-2 7.60E-2 Sum 5.88E-1 5.07 E- 1 2.20E-l 1.93 E- l

• I In 1986, some of the deposited material from 1979 was moved to outside the bermed storage area to make room for the 1986 material.

Table 1-2 Summary of Total Dose Rate by Pathway in 1998 (at t=12 years)

Time (t) = 12 years External inhalation Aquatic Foods Drinking Water (1998)-+ (Ground) (Fish) j Total IIIfective Dose Equivalent Rate (mrem /yr)

Model #1 - 79 in berm

• 4.73E-8 0.00 0.00 0.00 Model #2 - 86 in herm 1.30E-1 1.39E-6 0.00 0.00 Model #3 - 79 out berm

• 9.03E-2 1.05 E-6 7.90E-6 5.1 l E-5 Sum 2.20E-1 2.A4 E-6 7.90E-6 5.11 E .5 Characterization Efforts Characterization of the area containing the dredging materials was initiated in 1997. The surve; results from approximately forty (40) soil samples show no detectable levels of Co-60 (lower limit of detection ~ 0.02 pCi/g) and only background levels of Cs-137.

CYAPCO will further characterize this area as part its ongoing site characterization program.

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U. S. Nuclear Regulatory Commission CY-98-062/Page 5 Conclusion ,

, The models used to estimate the dose from the dredging material stored on the peninsula j are based on conservative assumptions and parameters approved by the NRC for dose modeling of residual radioactivity in soil. The models show that at no time does the total  !

! effective dose equivalent from this material exceed 1 millirem in a year. The estimated

! l maximum dose is less than 1% of the 100 millirem per year dose limit imposed for  ;

members of the public under 10CFR20.1301(a). 1 l

. Furthermore, recent site characterization surveys of the area containing the dredge l materials indicate no detectable levels of Co-60 or Cs-137 above background levels. I Commitments l

Similar to 10CFR20.2002 applications, a copy of this letter and a copy of the current j assessment memorandum will be placed in the UFSAR. In addition, for purposes of final i

status survey, the dredge material area will be designated as impacted for further i investigation based on the limited past sampling of the material.

l l We trust this information is satisfactory to resolve the inspection open issues. If you have I any questions or desire additional information, please contact Mr. Gerry P. van Noordennen at (860) 267-3938. i

i i i Very truly yours, CONNECTICUT YANKEE ATOMIC POWER COMPANY f

um T- ., -

RusseibA. Mellor \

Vice President Operations and Decommissioning i l

l l

l cc: H. J. Miller, Region I Administrator T. L Fredrichs, NRC Project Manager, Haddam Neck Plant L J. Raymond, Senior Resident Inspector, Haddam Neck Plant

! E. Wilds, Director, CT DEP, Radiation and Monitoring Division

! P. G. Hill, CT DEP, Bureau of Water Management 2

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