ML081200351

Estimated Dose Report for 2007, Connecticut Yankee Independent Spent Fuel Storage Installation

ML081200351
Person / Time
Site:	Haddam Neck  File:Connecticut Yankee Atomic Power Co icon.png
Issue date:	04/15/2008
From:	Radiological Safety & Control Services
To:	NRC/FSME, Office of Nuclear Material Safety and Safeguards
References
CY-08-009
Download: ML081200351 (7)

Text

ESTIMA TED DOSE REPORT FOR 2007 CONNECTICUT YANKEE ISFSI INDEPENDENT SPENT FUEL STORA GE INS TALLA TION License No. DPR-61 CONNECTICUT YANKEE ISFSI

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April 2008 Prepared by:

Radiological Safety & Control Services 91 Portsmouth Avenue Stratham, NH 03885-2468

TABLE OF CONTENTS Page TABLE OF CONTENTS........................................................................................

I LIST OF TABLES................................................................................................

2

1.0 INTRODUCTION

3 2.0 DOSE ASSESSMENT..................................................................................

3

3.0 REFERENCES

4 I

LIST OF TABLES TABLE TITLE Page TABLE 1 CONNECTICUT YANKEE ISFSI Maximum Annual Dose from Direct External Radiation for 2007(a)(40CFR190)......................................................................

5 TABLE 2 Receptor Locations for the Connecticut Yankee ISFSI......................................

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CONNECTICUT YANKEE ISFSI ESTIMATED DOSE REPORT FOR 2007

1.0 INTRODUCTION

The Connecticut Yankee ISFSI is designed with the NAC-MPS Transportable Storage Containers that are stored in Vertical Concrete Cask. Per the NAC-MPS Safety Analysis Report, and the 10 CFR 72.212 Evaluation, this type of design meets the definition of a leak tight canister as defined by as defined by ANSI N 14.5. As such, there are no liquid, particulate, or gaseous effluents resulting from ISFSI operations. The only dose to be considered from facility operations is from direct radiation.

For the purposes of demonstrating compliance with 40CFR190, "Environmental Radiation Protection Standards for Nuclear Power Operations," radiation dose estimates must include direct radiation contributions from significant plant sources. Data from thermoluminescent dosimeters (TLDs) in the area of the southwestern ISFSI controlled area boundary was used for this dose assessment.

The total dose to the most limiting member of the public due to ISFSI related direct radiation was well below the dose standards of40CFRI190.

2.0 DOSE ASSESSMENT The annual (calendar year) total dose to any member of the public due to direct radiation from fixed sources are limited to EPA's radiation protection standards for the uranium fuel cycle (40CFR190). The dose limits are set to less than or equal to 25 mrem per year to the total body or any organ, except the thyroid, which is limited to less than or equal to 75 mrem per year.

Direct external dose from fixed sources of radioactive materials within the ISFSI controlled area was estimated from Connecticut Yankee TLD data. The data from TLDs posted in the south and west sectors of the ISFSI controlled area boundary were used for this dose estimation. The dose estimate is performed to determine to potential dose to any real member of the public along the southwest boundary where individual members could occupy the Connecticut River for recreational activities throughout the year. The maximum annual dose from fixed radiation sources to members of the public along the Connecticut River shoreline, as derived from TLD measurements, was estimated to be 0.51 mrem. This estimate of dose incorporates an occupancy time of 500 hours0.00579 days <br />0.139 hours <br />8.267196e-4 weeks <br />1.9025e-4 months <br /> per year as a reasonable occupancy factor for a real member of the public conducting such activities. The receptor location used for the dose estimation is that containing TLD CY-53-1F. It must be considered however, that the location used by the public is situated further away from this selected reference point TLD. As a result, actual exposure from direct radiation would be less than the value applied in the estimate of direct dose (0.51 mrem) as the dose calculation makes no attempt to apply a "distance" correction factor to the onsite TLD measurement for the purpose of obtaining the exposure rate to the Connecticut River. The dose rate at that location would be much less as a function of distance.

Table I provides the quarterly and annual dose to the maximally exposed member of the public from direct radiation associated with ISFSI operations.

Table 2 identifies the receptor locations nearest resident to the Connecticut Yankee ISFSI.

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3.0 REFERENCES

I.

"Off-Site Dose Calculation Manual," Connecticut Yankee ISFS1.

2.

40CFR190, Environmental Radiation Protection For Nuclear Power Operations

5.

NUREG-0133, "Preparation of Radiological Effluent Technical Specifications for Nuclear Power Plants,"

U.S. Nuclear Regulatory Commission, Office of Nuclear Reactor Regulation, October 1978.

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TABLE 1 CONNECTICUT YANKEE ISFSI Maximum Annual Dose from Direct External Radiation for 2007(a)

(40CFR190)

Pathway Ist Qtr.

2 r

4tr Qtr.

Year Direct External Exposure Rate (Micro-R/hr) 0.20(c) 1.00(c) 7.87E-1 avg.

Occupancy Hours/interval 50(a) 200(a) 200(a) 50(a) 500(a) 3.00E-2 3.93E-1(b) mrem/interval 1.00E-2 2.OOE-1 2.70E-1 use avg. exp. rate 1.0 E-2 + 2.0E-I + 2.70E-1 + 3.OE-2 5.1 E-1 mrem (value applied in dose estimate)

(a)

The location of maximum individual doses from direct radiation corresponds to the south west sector of the Connecticut Yankee ISFSI. Whereas the hours per interval were proportioned to a reasonable time that any real member of the public would conduct recreational activities along the shore of the Connecticut River. The annual occupancy (500 hours0.00579 days <br />0.139 hours <br />8.267196e-4 weeks <br />1.9025e-4 months <br /> per year) is a reasonable assessment for determining the direct dose component to a real member of the public for demonstrating compliance with 40CFR190.

(b)

For any member of the public, EPA radiation protection standards (40CFR190) established annual dose limits of 25 mrem to the total body and any organ (except the thyroid, which has a dose limit of 75 mrem).

(c)

Exposure rate above the average background of the Connecticut Yankee offsite TLD locations (Hurd Park Road). For this dose estimate, the TLD location with the highest annual average was used (CY-10-IFC).

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TABLE 2 Receptor Locations for the Connecticut Yankee ISFSI Nearest Resident Sector (Meters)

N 1.18 NNE NNE 1.74 NE 1.69 ENE 1.75 E

2.12 ESE 2.75 SE 1.34 SSE 1.20 S

1.04 SSW 0.93 SW 1.03 WSW 1.22 W

1.40 WNW 0.64 NW 1.09 NNW 1.55 The receptor locations noted represent the closest dry land points beyond the site boundary where a 100% occupancy time is assumed.

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