ML16350A042

Supplemental Information Relicensing for the Rhode Island Nuclear Science Center (R-95)

ML16350A042
Person / Time
Site:	Rhode Island Atomic Energy Commission
Issue date:	12/15/2016
From:	Goodwin C State of RI, Atomic Energy Comm, Nuclear Science Ctr
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
Download: ML16350A042 (67)

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STATE OF RHODE ISLAND AND PROVIDENCE PLANTATIONS Rhode Island Atomic Energy Commission 16 Reactor Road Narragansett, RI 02882-1165 Telephone#401-874-2600 Executed on: December 15, 2016 Docket No.50-193 License No.R-95 U.S.Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C.20555-0001

Subject:

Supplemental Information Re: Relicensing for the Rhode Island Nuclear Science Center (R-95)Mr.Boyle, This letter and attachment contains supplemental information in support of the Rhode Island Nuclear Science Center's (RINSC's)relicensing effort.Our response includes 2 enclosures.

The enclosures contain the facilities fuel failure analysis and the fissionable experiment analysis.We are also including the fact that the make-up system provides a make-up rate of 5 gallons per minute..If there are any questions regarding this matter, please feel free to contact me at (401)874-2600.Sincerely, Cameron Goodwin, PhD, Director Rhode Island Nuclear Science Center I certifyunderpenalty of perjury that the representations made above are true and correct.cc: A Adams Mr.Craig Bassett 5523 Preserve Point Flowery Branch, GA 30542 1 Fuel Failure Analysis 161114 Radionuclides Released from Fuel Failure 1. The available regulatory guidance regarding the quantity of radioactive material that gets into the coolant from the damaged fuel is geared toward nuclear power plants, rather than low power research reactors. The guidance is divided into information that pertains to low pressure boiling water reactors (BWR), versus information related to high pressure, pressurized reactors (PWR). Of the two types of reactors, the RINSC reactor is more similar to a BWR than a PWR. Consequently, the guidance for BWRs was used. 2. The radionuclides that are expected to be released as a result of gap and early in-vessel fuel failure have been grouped on the basis of chemical similarity4. There are seven groups that are expected to get into the coolant5: Group Elements Noble Gases Xe, Kr Halogens I, Br Alkali Metals Cs, Rb Tellurium Group Te, Sb, Se, Ba, Sr Noble Metals Ru, Rh, Pd, Mo, Tc, Co Lanthanides La, Zr, Nd, Eu, Nb, Pm, Pr, Sm, Y, Cm, Am Cerium Group Ce, Pu, Np 3. Regulatory Guide 1.183 indicates that during the gap and early in-vessel release phases of fuel failure, the release fractions from the fuel to the confinement air are6: Group Gap Release Phase Early In-Vessel Release Phase Total Noble Gases 0.05 0.95 1.0 Halogens 0.05 0.25 0.3 Alkali Metals 0.05 0.20 0.25 Tellurium Metals 0.00 0.05 0.05 Ba, Sr 0.00 0.02 0.02 Noble Metals 0.00 0.0025 0.0025 Lanthanides 0.00 0.0002 0.0002 Cerium Group 0.00 0.0005 0.0005 4. All of the fission products that are released from the fuel are in particulate form except for7:

2 A. Elemental Iodine (I2) B. Organic Iodide C. Noble Gases 5. Particulates: A. The particulates are assumed to be retained by the water in the pool11. Consequently, only the iodines and noble gases must be considered in the analysis. 6. Iodine: A. If there were not an appreciable amount of coolant acting as a barrier between the fuel and the confinement air: 1. The chemical form of the iodine that is released from the coolant into the confinement air would be7: A. Cesium Iodide (CsI) 95% B. Elemental Iodine (I2)4.85% C. Organic Iodide 0.15% 2. The cesium iodide is expected to completely dissociate in the pool water, after which, the iodine is expected to re-evolve as elemental iodine (I2) due to the low pH of the water relatively instantaneously8. B. However, RINSC Technical Specifications require that the height of the pool water over the top of the fuel meat be at least 23 feet 7 inches for both natural convection operation, and forced convection operation9. C. If the depth of the water above the damaged fuel is 23 feet or greater, then 99.5% of the total iodine in the coolant remains in there, and the composition of the iodine that reaches the confinement air is10: 1. Elemental Iodine (I2) 57% 2. Organic Iodide 43% 7. Noble Gases: A. The retention of the noble gases in the pool water is assumed to be negligible11. 8. Therefore, the isotopes that are relevant due to the fact that a significant fraction of them will be transported to the confinement air are the iodines and noble gases.

3 A. Given the fact that at the RINSC reactor the water depth is at least 23 feet over the fuel meat, the fraction of the halogens that are released into the pool water that will reach the confinement air is 0.5% of the content in the coolant. B. The noble gases will be unaffected by the coolant, so it is anticipated that 100% of the noble gases that are released into the pool water will reach the confinement air. Highest Power Fuel Plate Activity Inventory 1. Highest Power Fuel Plate A. The memo regarding the Steady-State Thermal-Hydraulic Analysis for Forced-Convective Flow in the Rhode Island Nuclear Science Center (RINSC) Reactor, indicates that power of the highest power plate during full power reactor operation at 2 MW is 9.653 kW.13 2. Fission Rate A. The energy associated with each fission event that occurs in the reactor is 200 MeV per fission. B. Converting from MeV to MW Seconds: = 3.2 X 10-17 MW second per fission C. Therefore the fission rate at 1 MW power is: D. In order to generate 9.653 kW of power in the highest power fuel plate, the fission rate in that plate must be: = 2.992 X 1014 fission / second ~ 3 X 1014 fission / second 2. Fission Nuclide Production Rate 4 A. The fission nuclide production rate for the i th fission product nuclide is the i) for the i th fission product: Fission Nuclide Production Rate = (3 X 1014 i) 3. Fission Nuclide Decay Rate A. The fission nuclide decay rate for the i th fission product nuclide is the i), and the number of atoms of the nuclide that are present (Ni): i)(Ni) 4. Fission Product Saturation A. Fission product saturation occurs when the production rate and decay rate are the same. Therefore, for the i th fission product, saturation is when: (3 X 1014 ii)(Ni sat) B. Therefore, if we wanted to estimate the number of atoms of the i th fission product in the highest power fuel plate at saturation, it would be: C. However, if we want to estimate the activity of the i th fission product in the highest power fuel plate at saturation, it would be: i)(Ni sat) = (3 X 1014 i) D. The activity can be converted to units of Ci by using the conversion factor: 1 Ci = 3.7 X 1010 Bq 5. As an example, consider I-atoms per fission-7 per second: A. Saturation Activity in the Highest Power Fuel Plate = 8.3 X 1012 I-131 atoms per second 5 = 8.3 X 1012 Bq I-131 = 2.25 X 102 Ci B. Most of the fission products do not get out of the fuel matrix. Of the isotopes that get into the pool water, there is so much solvent in comparison to solute that the vast majority of the isotopes would stay dissolved in the pool water14. The fission products that are both volatile and long lived enough to potentially escape from the fuel matrix to the pool, as well as the decay constants and cumulative fission yields of each of those isotopes are15: Note that the fission yields are cumulative, and include not only the yield of the nuclide, but also take into account the yields of the short lived precursors as well. Source Term 1. If a fuel plate were to be completely denuded on one side, the amount of the plate activity that would be available to be released would depend on the temperature of the fuel, and the surface area of the fuel that is exposed. Since the fuel temperature even during full power operation is very low, diffusion from the fuel matrix would be essentially zero. Consequently, the only fission products that would be available to get into the confinement air would be from the denuded surface due to the kinetic energy associated with fission fragment recoil. 2. As a result, of the total fission fragment inventory in the damaged fuel plate, the fraction of the activity that could be released is the fraction that is in the volume 6 defined by the surface area of the exposed fuel matrix, and the fission fragment recoil depth. 3. Therefore, we can estimate the source term that is available to be released to the confinement air by finding the ratio between the volume of the fuel meat that is within the recoil range, to the total volume of the fuel meat. Using the minimum fuel meat volume maximizes the activities in the release volume, and is therefore conservative. 3. NUREG / CR-2079 PNL-3691 Analysis of Credible Accidents for Argonaut Reactors indicates that the range of fission fragment recoil in aluminum is: 1.37 X 10-3 cm 4. For the RINSC reactor, the minimum total volume of the fuel meat is17: Length = (22.50 inches)(2.54 cm) / in = 57.15 cm Width = (2.32 inches)(2.54 cm) / in = 5.89 cm Thickness = (0.020 inches)(2.54 cm) / in = 0.05 cm Total Fuel Meat Volume = (57.15 cm)(5.89 cm)(0.05 cm) = 16.83 cm3 5. If a fuel plate were stripped of one side of the cladding, the volume within the recoil range of the fission fragments would be: (57.15 cm Length)(5.89 cm Width)(1.37 X 10-3 cm) = 0.46 cm3 6. The ratio of fission fragments that are available to be released to the coolant, to the total fuel plate fission fragment inventory is: (0.46 cm3)(16.83 cm3) = 0.027 = 2.7% 7. Therefore, the activity that is available to be released from the fuel into the confinement air is only 2.7% of the fuel plate activity. Overall:

7 Coolant Activity 1. All of the source term activity is assumed to be released to the coolant, so the release fractions for both the iodines, and the noble gases are one. Confinement Air Activity 1. Of the activity that is available to be released to the confinement air, the fractions that are released to the air are: A. Halogen Release Fraction = 0.005 B. Noble Gas Release Fraction = 1.0 8 Volume of Confinement A negative pressure is maintained in the confinement building so that all of the air that exits the buiding will exit through a stack. If an airborne RAM release is detected, the Emergency Air Handling System is activated, and the airflow is directed through an emergency filter prior to reaching the stack. During facility re-licensing, the volume of the confinement building was determined to be approximately 203,695 cubic feet. The volume of the pool structure and water was determined to be 21,740 cubic feet, leaving 181,955 cubic feet of open space. The control room takes up about 3,612 cubic feet of this space. Converting the free volume of the confinement room to cubic centimeters: Confinement Concentration If we assume that the activity that is released into confinement is spread out uniformly over the entire volume of the confinement, the concentrations of each isotope would be:

9 Emergency Filter Exhaust Activity Release Rate 1. When the Emergency Air Handling System is activated, all of the air from the confinement room is exhausted through an emergency filter. The emergency filter consists of: A. Roughing Filter B. HEPA Filter C. Charcoal Filter D. HEPA Filter 2. The proposed Technical Specifications associated with the Emergency Filter efficiency are: 3.5.2.3 The emergency filter shall be at least 99% efficient at removing iodine. 3.5.2.4 The Emergency Filter System Exhaust Absolute Filter shall be certified by the manufacturer to have a minimum efficiency of 99.97% for removing 0.3 micron diameter particulates. 3. Of the iodine that reaches the stack, only the non-organic iodine is adsorbed by the charcoal filter. The organic iodine is not adsorbed. 4. The concentration of non-organic iodine in the confinement room that will reach the stack is: (1%)(Confinement Concentration) 10 = (0.01)(Confinement Concentration) 5. The noble gases are unaffected by the HEPA filters, but are slowed by the charcoal filter. We will assume that all of the noble gases are released to the stack. 6. If we continue with our I-131 example: A. We concluded that the concentration of I-131 in the confinement air was 5.89E-6 Ci / cm3. B. Of this concentration of iodine, the relative amounts of organic and non-organic iodine are: (43% Organic Iodine)(5.89E-Ci / cm3) = 2.53 X 10-6 Ci / cc (57% Non-Organic Iodine)(5.89E-Ci / cm3) = 3.36 X 10-6 Ci / cc D. All of the organic Iodine is assumed to get through the filter, and only 1% of the non-organic iodine is assumed to get through. Therefore, the total amount that gets through the filter is: 2.53 X 10-6 + (0.01)( 3.36 X 10-6 ) = 2.57 X 10-6 Ci / cc E. Overall 11 Stack Radioactive Material Release Rate 1. The dispersion calculations use radioactive material release rates, rather than activity concentrations. 2. The rate at which RAM is exhausted from the stack is equivalent to the rate at which it is exhausted from the emergency filter. 3. The higher the filter exhaust flow rate, the higher the RAM release rate from the stack. 4. Technical Specification 3.5.2.2 limits flow through the emergency filter to a maximum of 1500 cfm. 5. Therefore, the RAM release rate from the stack is: 6. Continuing with the I-131 example, the concentation of I-131 in the emergency filter exhaust was 2.57 X 10-6 Ci / cm3, so the I-131 release rate is: 7. Overall:

12 Atmospheric Dispersion 1. Air Turbulance Conditions A. Non-Fumigation Conditions Atmospheric stability is a measure of the turbulence in the plume, and it affects the rate of the dispersion of the plume. The more turbulent the air is, the greater the dispersion rate. There are six classifications of atmospheric stability, ranging from Pasquill Type A through Pasquill Type F, in which A is extremely unstable, and F is moderately stable. While this suggests that Pasquill Type F is conservative because it minimizes the dispersion rate and maximizes the airborne RAM concentrations at ground level, it is not necessarily the most conservative from the standpoint of the distance at which the plume reaches ground level. B. Fumigation Conditions Fumigation is a condition in which there is an air inversion above the stack release which forces the plume to stay below the inversion. As a result, under fumigation conditions, the plume reaches the ground level at distances that are much shorter than what occurs under non-fumigation conditions. NRC Regulatory Guide 1.145 Section 2.1.2.b indicates that for coastal sites that are located less than 3.2 kilometers from a large body of water, fumigation conditions should be assumed to exist.

13 C. Conditions Under Consideration Since the stack is approximately 150 meters from the Narragansett Bay, fumigation conditions were considered to be the predominant condition. 2. Dispersion Equations A. Atmoshperic dispersion calculations estimate the concentration of some material in air for a given release rate, under specified atmospheric conditions, at some distance away from the source. A Gaussian Straight Line Plume Model is used. B. Fumigation Equation Section 1.3.2.b of NRC Regulatory Guide 1.145 (November 1982 Rev. 1) indicates that the equation for stack releases under fumigation conditions is: C. The factors for this equations is: 1. 2. Q is the material release rate (Activity / Time) 3. y is the horizontal dispersion coefficient (Distance) 4. z is the vertical dispersion coefficient (Distance) 5. hs is the stack height above the plant grade (Distance) 6. ht is the maximum terrain height above plant grade between the release point, and the point of interest (Distance) 7. he is the effective stack height = hs ht with he = 0 if ht> hs (Distance) 8. uhe is the average wind speed of the fumigation layer at the effective stack height (Distance / Time) 9. x is the downwind distance (Distance) 10. y is the horizontal distance at right angles to the plume centerline (Distance) 11. z is the height above the ground (Distance) 3. Stack Height The release is at the level of the stack (hs = 115 ft), with no significant change in terrain height between the release point and the site boundary (ht = 0), so the effective stack height is:

14 he = hs ht = 35m = 0 = 115 ft = (115 ft)(12 in / ft)(2.54 cm / in)(m / 100 cm) = 35.052 m 4. Wind Direction Wind direction is assumed to be constant, As a result, all of the concentration of RAM will be along one line of direction, rather than dispersed across more than one direction. Consequently, this assumption is conservative. 5. Wind Speed The wind speed is assumed to be one meter per second. Higher wind speeds increase dilution because the RAM released per unit time is added to a larger volume of air passing by the release point. Consequently, this assumption is conservative. 6. Coordinates of Interest The dispersion coefficents are quantitative measures of how much the plume spreads out in the horizontal (y) and vertical (z) directions at some given distance (x) down wind of the release point. The material concentration in the plume as a function of distance from the plume centerline is a Gaussian distribution, with maximum concentration at the centerline. The dispersion coeficients are the standard deviations y distance from the centerline in the y z distance from the centerline in the z direction. For this analysis, the y and z values are taken to be zero so that the concentrations calculated will be associated with the centerline of the plume, and therefore will be the most conservative. The distance between the confinement stack and the site boundary is 50 meters. RINSC has the authority to prevent the public from entering this boundary. The facility sits on the Bay Campus of the University of Rhode Island. There are residential areas to the north and south of the campus. To the west of the campus, woods and businesses abut the campus. To the northwest along South Ferry Road, there are residences as well. Using Google Maps to estimate the distances between the stack release point, and the residences to the north, nothwest, and south, the nearest residence was determined to be 500 meters from the stack:

15 Distance to Nearest Residence on South Ferry Road Distance to Nearest Residence in Saounderstown Disatance to Nearest Residence in Bonnet Shores Therefore the closest residence is 1600 feet from the stack: The maximum concentration point occurs whenNeed

Reference:

z)2 = (he)2 From this, the maximum concentration point is the x distance from the stack that z that was calculated. In addition to calculating where the maximum concentration point occurs, numerical methods were used to verify that itt occurs where it is predicted to occur. Consequently, the three points down wind of the stack that we are interested in knowing the RAM concentrations at ground level are: 1. Site Boundary (x = 50 meters) 2. Nearest Residence (x = 500 meters) 3. Maximum concentration point The dispersion coefficients take these distances into account. The dispersion 103 are:

16 7. NRC Regulatory Guide 1.145 section 1.3.2.b provides the dispersion equation for fumigation conditions, and indicates that: A. B. A wind speed of u = 2 meters / second is considered to be conservative. Since the initial conservative assumption was made that the wind speed is u = 1 meter / second, and this is more conservative that an assuption of 2 meters / second, the analysis was done with u = 1 meter / second. C. y is determined under air turbulent conditions of Pasquill F. 1. The Site Boundary distance from the stack is 50 meters. 2. y dispersion coefficient at 50 meters is: y is at 50 meters for the Pasquill F y vs. x graph, two data points are: x1 = 100 m y1 = 4 m x2 = 200 m y2 = 8 m The slope of the line is: = = = 0.04 The point slope form of the line is: (y2 y1) = m(x2 x1) The y intercept occurs at point (0,b): (y2 b) = m(x2 0) (y2 b) = mx2 y2 mx2 = b 17 b = y2 mx2 b = (8 m) (0.04)(200 m) = 0.0 m Consequently, the general equation is: y = mx + b y = (0.04) x + 0.0 m y is: y = y = (0.016)(50 m) + 0.08 m = 2.0 m 8. Consequently, the values of each of the factors in the fumigation dispersion equation are: he = 35.052 m uhe = 1 m / s y = 2.0 m 9. Plugging these values into the non-fumigation dispersion equation: = 5.69 X 10-3 s / m3 Converting the volume to units of cm3: = (5.69 X 10-3 s / m3)(m / 100 cm)3 = 5.69 X10-9 s / cm3 10. Using this to convert the stack release rate of I-131 into a concentration: For I-131, the release rate out of the stack was 1.82 X 100 Ci / s. (1.82 X 100 )(5.69 X10-9 s / cm3) = 1.04 X 10-8 Ci / cm3 This is the concentration of I-131 at ground level, at a distance of 50 meters down wind of the stack, if the air turbulance is in a fumigation condition, and the wind speed is 1 m / s.

18 11. Methodology for Determining Concentrations at the Site Boundary, Nearest Residiential, and Maximum Concentration Points A. In order to get a sense of where the maximum concentration point is, dispersion coefficients were determined for distances ranging from the 50 meter site boundary point, to 10,000 meters out from the stack, including the 500 meter residential point. B. X/Q was calculated for each of these distances. C. Isotope concentrations were calculated for each of these distances, and the distance with the highest concentration data was highlighted. D. A second set of dispersion coefficients were determined for distances at smaller increments around the point of maximum concentration found in the first set of data, in order to get a more precise location. E. X/Q was calculated for each of these new distances. F. Isotope concentrations were calculated for each of these new distances, and the distance with the highest concentration data was highlighted. The distance associated with these concentrations is the maximum concentration point. G. Additionally, the point of maximum concentration was also calculated using the following formulaNeed formal reference for Ronald Fjeld, Quantitative Environmental Risk Analysis : 2(z)2 = (he)2 and solving for z. z vs. x graph was used to determine the distance x associated with the z. This distance is the predicted point of maximum concentration point. H. For each case, both methods for determining the maximum concentration point were found to be consistent with each other.

19 12. Fumigation Results 20 13. RAM Concenterations at Points of Interest Dose Limits 1. Dose Calculation Background Information A. Health effects of radiation dose are separated into two categories: 1. Stochastic Effects These effects are probabilistic, and are due to random ionization events. Consequently, there is no threshold for these effects, and the probability of occurrence is proportional to the dose received. Cancer is an example of these types of effects. 2. Non-Stochastic Effects These effects depend on the amount of dose received beyond a minimum threshold, and the amount of damage depends on the magnatude of the dose. Skin erythmia is an example of a non-stochastic effect. B. The objective of dose limits are to minimize the risk of stochastic effects, and to prevent the occurrence of non-stochastic effects. The dose limits have been designed to be independent of whether or not the radiation dose is uniform or non-individual organ and equates it to the risk associated with a uniform irradiation of the whole body.

21 2. Definitions A. Allowable Limit on Intake (ALI) This is the amoung of RAM taken into the body via ingestion or inhalation that would lead to a committed effective dose equivalent of 5 Rem, or 50 Rem to any individual tissue or organ. B. Derived Air Concentration (DAC) This is the concentration of a given radionuclide in air which if inhaled at a rate of 2 X 104 cm3 per minute for one working year (2000 hours0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br />) would result in reaching the ALI. Therefore, as an example, I-131 has a DAC = 2 X 10-8 3 and an ALI = This means that if the reference man were to breath in the DAC for 2000 hours0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br />, at a rate of 2 x 104 equivalent to the ALI. C. Derived Air Concentration - Hour (DAC - Hour) This is the product of the concentration of RAM in the air expressed as a fraction or multiple of the DAC, and the exposure time expressed in hours. D. Absorbed Dose (D) This is a measure of the radiation energy that is absorbed per unit mass of material of interest. E. Dose Equivalent (H) This is the product of the absorbed dose in tissue, quality factor (Q), and all other necessary modifying factors at the location of interest. The units of dose equivalent are the rem and sievert (Sv). In general: H = DQ F. Quality Factor (Q) This is a regulatoraly defined factor to account for the fact that the type and energy of the incident radiation has an effect on the amount of biological damage that is produced per unit of absorbed energy (absorbed dose). G. Tissue Dose Equivalent (HT) This is the dose equivalent to a specific tissue or organ due to external sources. H. Committed Dose Equivalent (HT,50) This is the dose equivalent to organs or tissues of reference (T) that will be received from a single intake of radioactive material by an individual that will be accumulated over the 50-year period following the intake.

22 I. Effective Dose Equivalent (HE) This equates the risk of a non-uniform external dose, or internal dose to the risk associated with a dose that is distributed uniformly over the whole body. A regulatoraly defined weighting factor (WT) is used for each organ, and the overall effective dose equivalent is: HE THT This is the sum of the products of the dose equivalent to the organ or tissue (HT) and the weighting factors (WT) applicable to each of the body organs or tissues that are irradiated (HE THT). J. Committed Effective Dose Equivalent (HE,50) This is the effective dose equivalent accumulated over a 50 year period as a result of a single intake of radioactive material. In general: HE,50 THT,50 This is the sum of the products of the weighting factors applicable to each of the body organs or tissues that are irradiated and the committed dose equivalent to these organs or tissues (HE,50 THT,50). K. Deep Dose Equivalent (DDE) This is the whole body dose at a depth of 1 cm due to an external exposure. L. Total Effective Dose Equivalent (TEDE) This is the sum of the DDE due to an external dose, and the CEDE due to an internal dose from an intake of radioactive material. In general: TEDE = DDE + CEDE 3. Regulatory Limits10 CFR 20 A. Occupational Dose Limits 1. TEDE = 5 rem / yr [10 CFR 20.1201(a)(1)(i)] 2. DDE + CDE to any individual organ or tissue = 50 rem / yr [10 CFR 20.1201(a)(1)(ii)] 3. to demonstrate compliance with dose limits. [10 CFR 20.1201(d)] 4. If the only intake of radionuclides is by inhalation, the total effective dose equivalent limit is not exceeded if the sum of the deep-dose equivalent divided by the total effective dose equivalent limit, and one of the following, does not exceed unity [10 CFR 20.1202(b)]:

23 A. The sum of the fractions of the inhalation ALI for each radionuclide, or B. The total number of derived air concentration-hours (DAC-hours) for all radionuclides divided by 2,000, or C. The sum of the calculated committed effective dose equivalents to all significantly irradiated1 organs or tissues (T) calculated from bioassay data using appropriate biological models and expressed as a fraction of the annual limit. 5. If the identity and concentration of each radionuclide in a mixture are known, the fraction of the DAC applicable to the mixture for use in calculating DAC-hours must be either [10 CFR 20.1204(e)]: A. The sum of the ratios of the concentration to the appropriate DAC value (e.g., D, W, Y) from appendix B to part 20 for each radionuclide in the mixture; or B. The ratio of the total concentration for all radionuclides in the mixture to the most restrictive DAC value for any radionuclide in the mixture. 6. In order to calculate the committed effective dose equivalent, the licensee may assume that the inhalation of one ALI, or an exposure of 2,000 DAC-hours, results in a committed effective dose equivalent of 5 rems (0.05 Sv) for radionuclides that have their ALIs or DACs based on the committed effective dose equivalent. [10 CFR 20.1204(h)(1)] 7. When the ALI (and the associated DAC) is determined by the nonstochastic organ dose limit of 50 rems (0.5 Sv), the intake of radionuclides that would result in a committed effective dose equivalent of 5 rems (0.05 Sv) (the stochastic ALI) is listed in parentheses in table 1 of appendix B to part 20. In this case, the licensee may, as a simplifying assumption, use the stochastic ALIs to determine committed effective dose equivalent. However, if the licensee uses the stochastic ALIs, the licensee must also demonstrate that the limit in § 20.1201(a)(1)(ii) is met. [10 CFR 20.1204(h)(2)] B. Dose Limits for Individual Members of the Public 1. TEDE = 100 mrem / yr [10 CFR 20.1301(a)(1)] 2. A licensee shall show compliance with the annual dose limit in § 20.1301 by [10 CFR 20.1302(b)]: A. Demonstrating by measurement or calculation that the total effective dose equivalent to the individual likely to receive the highest dose from the licensed operation does not exceed the annual dose limit or 24 B. Demonstrating that: 1. The annual average concentrations of radioactive material released in gaseous and liquid effluents at the boundary of the unrestricted area do not exceed the values specified in table 2 of appendix B to part 20; and 2. If an individual were continuously present in an unrestricted area, the dose from external sources would not exceed 0.002 rem (0.02 mSv) in an hour and 0.05 rem (0.5 mSv) in a year. 4. External Immersion Dose vs. Internal Dose For the fuel failure accident we are concerned about the doses that individuals will recieve due to airborne radioactive materials. The airborne RAM that is released in these types of accidents consist of halogens, such as iodine, and noble gases, such as xenon and krypton. When halogens are inhaled, part of what is inhaled is taken up and incorporated into the body. Consequently, these isotopes cause a committed internal dose. Noble gases are inert, so when they are inhaled, they are not taken up and incorporated into the body. Consequently, these isotopes cause an external immersion dose and do not contribute to an internal dose. During a fuel failure accident, the principle halogen that is released as an airborne RAM source is iodine. When iodine is uptaken into the body, it concentrates in the thyroid. As a result, the internal dose associated with a fuel failure accident would be the Committed Dose Equivalent (HT,50) to the thyroid due to iodine. A regulatoraly defined weighting factor (WT) is used to equate the risk of a non-uniform external dose, or internal dose to the risk associated with a dose that is distributed uniformly over the whole body. The product of the Committed Dose Equivalent and the weighting factor is the Committed Effective Dose Equivalent accumulated over a 50 year period as a result of a single intake of radioactive material (HE,50). During a fuel failure accident, the principle noble gases that are released as airborne RAM sources are krypton and xenon. These isotopes are the are the sources for the external immersion dose. As a result, the external immersion dose that is associated with a fuel failure accident is the Deep Dose Equivalent (DDE) to the whole body due to the iodine, krypton, and xenon isotopes. The Total Effective Dose Equivalent (TEDE) is the sum of the Deep Dose Equivalent (DDE), and the Committed Effective Dose Equivalent(HE,50).

25 5. What We Must Show A. Therefore, based on the regulations, we must show that: 1. The occupational doses to individuals inside confinement are no greater than: A. TEDE = 5 rem B. CEDE to any individual organ or tissue = 50 rem / yr 2. The doses to the public at the site boundary, maximum concentration point, and nearest residence are no greater than: A. TEDE = 100 mrem / yr Dose Calculation Methodology 1. Use of the DAC to Determine the Committed Dose Equivalent to the Thyroid (CDE) A. The ALI and DAC for any given nuclide can be found in 10 CFR 20 Appendix B. For I-131, the inhalation values for occupational exposure are given to be: 1. ALI = 50 -131 will lead to a CEDE of 5 Rem, or 50 Rem to any individual tissue or organ. Since iodine concentrates in the thyroid, the ALI is based on a dose of 50 Rem to the thyroid. 2. DAC = 2 X 10-8 cm3 This means that if an individual inhales concentration of 2 X 10-8 cm3 I-131 at a rate of 2 X 104 cm3 per minute for 2000 hours0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br />, they would intake enough of the radionuclide to receive a CEDE of 5 Rem whole body, or 50 Rem to any individual tissue or organ: B. If an individual is immersed in an air concentration equivalent to one DAC, the average dose rate that they would be receiving would be: 1. Individual Tissue or Organ (in this case Thyroid):

26 C. Since this is the dose rate that is associated with an airborne RAM concentration of one DAC, we can relate the dose rate associated with being immersed in an airborne RAM concentration of one DAC by: D. We can express the concentration of any RAM in air as a fraction or multiple of the DAC: DAC Fraction (Multiple) = (Air Concentration) / (DAC) E. Therefore, if we had a concentration of 5.89 X 10-6cm3 of I-131 in the confinement air, the DAC fraction (multiple) if the occupational DAC were 2 X 10-8cm3 would be: DAC Fraction (Multiple) = (Air Concentration) / (DAC) = 294.5 DAC F. For the iodines, the committed dose to the thyroid is also dependent on the amount of time that the individual is immersed. If an individual were only in the concentration of iodine for 5 minutes (0.083 hr), then the DAC fraction can be reduced: Immersion DAC = (DAC)(Immersion Time) Immersion DAC = (294.5 DAC)(0.083 hr) = 24.4 DAC - hr G. If we know the concentration of RAM in air as a fraction or multiple of the DAC, then we can determine the committed dose rate that that an individual immersed in the air would recieve. Continuing with the I-131 example: H. If there is more than one nuclide in the air with the same dose rate associated with exposure (either whole body or individual organ), then the DAC fractions can be added together before determining the dose rate. Consider: 1. Suppose that the air has a concentration of 5.89 X 10-6cm3 of I-131, and 8.78 X 10-6cm3 of I-132 in it. The DAC fractions are:

27 (Air Concentration) / (DAC) Where the DAC is defined in 10 CFR 20 for each isotope 2. For I-131 the DAC fraction has been previously calculated to be 294.5 DAC. 3. For I-132, given that the DAC is 3 X 10-6cm3, the DAC fraction is: (8.78 X 10-6cm3) / (3 X 10-6cm3) = 2.93 DAC 4. Therefore the total DAC fraction is: Total DAC Fraction = 294.5 DAC + 2.93 DAC = 298 DAC 6. Both of these DACs are based on a committed thyroid dose of 50 rem per year, which means that the dose rate associated with an air concentration of one DAC is 25 mrem / DAC - hr. 7. Therefore the committed dose to the thyroid for an individual that is immersed for 5 minutes in air with a concentration of 5.89 X 10-6cm3 of I-131 and 8.78 X 10-6cm3 of I-132 would be: 2. Use of the DAC to Determine Deep Dose Equivalent (DDE) A. The DAC for any given nuclide can be found in 10 CFR 20 Appendix B. For Kr-85, the inhalation value of the DAC for occupational exposure are given to be: DAC = 1 X 10-4 cm3 This means that if an individual is immersed in a concentration of 1 X 10-4 cm3 Kr-85 for 2000 hours0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br />, they would receive a DDE of 5 Rem whole body. B. If and individual is immersed in an air concentration equivalent to one DAC, the average dose rate that they would be receiving would be: Whole Body:

28 C. Since this is the dose rate that is associated with an airborne RAM concentration of one DAC, we can relate the dose rate associated with being immersed in an airborne RAM concentration of one DAC by: D. We can express the concentration of any RAM in air as a fraction or multiple of the DAC: DAC Fraction (Multiple) = (Air Concentration) / (DAC) E. Therefore, if we had a concentration of 1.21 X 10-4cm3 of Kr-85 in the confinement air, the DAC fraction (multiple) if the occupational DAC were 1 X 10-4cm3 would be: DAC Fraction (Multiple) = (Air Concentration) / (DAC) = 1.21 DAC F. If we know the concentration of RAM in air as a fraction or multiple of the DAC, then we can determine the dose rate that that an individual immersed in the air would recieve. Continuing with the Kr-85 example: G. For a mixture of airborne radionuclides, the total dose rate can be determined either by summing the individual DAC fractions and multiplying the sum by the dose rate per DAC - hr: Or by finding the dose rate associated with each nuclide and summing the individual dose rates to get the total dose rate:

29 H. Consider: 1. Suppose that the air has a concentration of 1.21 X 10-4cm3 of Kr-85, and 5.65 X 10-4cm3 of Kr-85m in it. The DAC fractions are: (Air Concentration) / (DAC) Where the DAC is defined in 10 CFR 20 for each isotope 2. For Kr-85 the DAC fraction has been previously calculated to be 1.21 DAC. 3. For Kr-85m, given that the DAC is 2 X 10-5cm3, the DAC fraction is: (5.65 X 10-4cm3) / (2 X 10-5cm3) = 28.25 DAC 4. Therefore the total DAC fraction is: Total DAC Fraction = 1.21 DAC + 28.25 DAC = 29.46 DAC 5. Therefore the dose rate associated with the deep dose equivalent is: Halogen Dose Calculations for Personnel Inside Confinement 1. Confinement Committed Dose to the Thyroid (CDE) A. Halogens are an inhalation hazard because they are absorbed into the body. The halogen of interest in the case of a fuel failure is iodine. Iodine concentrates in the thyroid. Consequently, the DAC for each isotope of Iodine is based on the amount of isotope that will result in a 50 rem dose to the thyroid over a 2000 hour0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br /> year. We have calculated that an individual immersed in air with a concentration of RAM in it equivalent to one DAC would lead to an internal dose rate of 25 mrem / hr to the thyroid. B. Facility evacuation drills show that in the event of an evacuation, the confinement building can be evacuated within 5 minutes. Thererfore the projected dose from the gas release for individuals inside confinement when the fuel failure occurs is:

30 C. For the isotopes of interest: Therefore, if someone remains in confinement for five minutes, they will receive a committed does to the thyroide of: DE = 961 mrem D. The committed effective dose equivalent (CEDE) is the product of the total CDE and a regulatorily defined weighting factor (WT) for the organ of interest. In this case, we are interested in the thyroid dose. 10 CFR Part 20.1003 provides the weighting factor for the thyroid: WT = 0.03 E. Therefore the CEDE is: CEDE = (961 mrem)(0.03) = 28.8 mrem Noble Gas Dose Calculations for Personnel Inside Confinement 1. For the isotopes of interest, assuming an occupancy time of five minutes:

31 Therefore, if someone remains in confinement for five minutes, they will receive a committed does to the thyroide of: mrem Total Effective Dose Calculations for Personnel Inside Confinement 1. Total Effective Dose Equivalent (TEDE) This is the sum of the DDE due to an external dose, and the CEDE due to an internal dose from an intake of radioactive material. In general: TEDE = DDE + CEDE = 285 mrem + 29 mrem = 314 mrem Dose Calculations for General Public at Site Boundary and Maximum Concentration Point 1. 10 CFR 20 Appendix B indicates that for offsite doses to the public due to airborne releases, values listed in Table 2 column 1 should be used. These concentrations correspond to an annual dose of 100 mrem. 2. Therefore, if an individual is immersed in an air concentration equivalent to one DAC, the average dose rate that they would be receiving would be: 3. Section 1.3 of NRC Regulatory Guide 1.145 (November 1982 Rev. 1) indicates that a conservative estimation of site boundary doses can be determined by it assuming that an individual spends two hours at the site boundary immediately following an accident. 4. For the isotopes of interest, assuming an occupancy time of two hours:

32 Therefore, if someone remains in at the site boundary, which is also the maximum concentration point for two hours, they will receive a total effective dose of: = 14 mrem Dose Calculations for General Public at Nearest Residence 1. For the isotopes of interest, assuming an occupancy time of two hours: Therefore, if someone remains in at the nearest residence for two hours, they will receive a total effective dose of: mrem 33 Summary 1 Fissionable Experimen t RAM Release Analysis 161123 Methodology For the fuel failure analysis, an assumption was made that one side of the cladding for the highest power fuel plate was denuded, and all of the fission fragments within the recoil distance were released to the coolant.

This corresponded to a release fraction from the fuel plat e to the coolant of 2.7%.

For the experiment failure analysis, numerical methods were used to determine the release fraction that would lead to the regulatory dose limits.

The fuel failure analysis assumed that the accident occurred under water. Therefore, an assumption was made that while all of the noble gases were released from the coolant to the confinement air, only 0.5% of the halogens got into the air. For this analysis, it is assumed that the experiment could fail in open air, which would mean that the release fraction to the confinement air would be 100% for both, noble gases and halogens.

It is assumed that if a release occurs, personnel will remain inside confinement for not longer than five minutes.

Once in the air, the fuel failure analysis assumed that the concentration of radionuclides would be spread over the entire volume of confinement. This assumption is also made for the experiment failure analysis.

The major constituents of the radionuclides expected to be release from a fuel cladding failure are iodines and noble gases. The iodines are expected to be 57% non

-organic and 43% organic. These assumptions are made for the experiment failure analysis.

Confinement air is assumed to be exhausted through the emergency filter, which has release fractions of:

Non-Organic Iodine 1% Organic Iodine 100% Noble Gases 100% Once exhausted through the emergency filter, the air goes into the stack. The stack release is assumed to occur under fumigation conditions, which lead to a maximum concentration point at the site boundary.

Dose calculations are made for personnel inside confinement for five minutes, general public at the site boundary for two hours, and general public at the nearest residence for two hours.

2 Mass of Fissionable Material in a Fuel Plate For the fuel failure analysis, an assumption was made that one side of the cladding for the highest power fuel plate was denuded, and all of the fission fragments within the recoil distance were released to the coolant. If we start with the assumption that an experiment is fuelled with the amount of fissionable material in one fuel plate, then there would be:

275 22 = 12.5 Highest Power Fuel Plate Activity Inventory The fuel failure analysis showed that the saturation fission fragment inventory for the highest power fuel plate would be:

NuclideFissionNumberLamarshDecayHighest PowerHighest PowerYieldof SecondsHalf LifeConstantFuel Plate ActivityFuel Plate Activity(Atoms/Fission)(s)( /s)(Bq)(Ci)I-1310.02778.04 d8.64E+046.95E+059.98E-078.31E+122.25E+02I-1320.04132.28 h3.60E+038.21E+038.44E-051.24E+133.35E+02I-1330.067620.8 h3.60E+037.49E+049.26E-062.03E+135.48E+02I-1340.071852.3 m6.00E+013.14E+032.21E-042.15E+135.82E+02I-1350.06396.7 h3.60E+032.41E+042.87E-051.92E+135.18E+02Kr-85m0.01334.4 h3.60E+031.58E+044.38E-053.99E+121.08E+02Kr-850.0028510.76 y3.15E+073.39E+082.04E-098.55E+112.31E+01Kr-870.0237 76 m6.00E+014.56E+031.52E-047.11E+121.92E+02Kr-880.03642.79 h3.60E+031.00E+046.90E-051.09E+132.95E+02Xe-133m0.001892.26 d8.64E+041.95E+053.55E-065.67E+111.53E+01Xe-1330.06775.27 d8.64E+044.55E+051.52E-062.03E+135.49E+02Xe-135m0.010515.7 m6.00E+019.42E+027.36E-043.15E+128.51E+01Xe-1350.06729.2 h3.60E+033.31E+042.09E-052.02E+135.45E+02Fuel Plate ActivityLamarsh Half Life Note that the fission yields are cumulative, and include not only the yield of the nuclide, but also take into account the yields of the short lived precursors as well.

This corresponds to the saturation activity of 12.5 g of fissionable material.

Source Term Numerical methods were used to show that if a release fraction of 0.7% of the fuel plate activity inventory were released into the confinement air, it would result in reaching the regulatory dose limits for the committed dose to the thyroid for personnel inside confinement, and the dose to the general public at the site boundary.

3 This corresponds to a mass of:

(12.5 g fissionable material)(0.7%) = 0.0875 g = 87.5 mg fissionable material With this assumption, the experiment source term becomes:

(Highest Power Fuel Plate Activity)(0.7%) = Source Term NuclideHighest PowerSource TermFuel Plate Activity(Ci)(Ci)I-1312.25E+021.57E+00I-1323.35E+022.34E+00I-1335.48E+023.84E+00I-1345.82E+024.08E+00I-1355.18E+023.63E+00Kr-85m1.08E+027.55E-01Kr-852.31E+011.62E-01Kr-871.92E+021.35E+00Kr-882.95E+022.07E+00Xe-133m1.53E+011.07E-01Xe-1335.49E+023.84E+00Xe-135m8.51E+015.96E-01Xe-1355.45E+023.81E+00Source Term Quantity of RAM that Reaches Confinement Air An assumption is made that the experiment failure occurs in air, rather than in the reactor pool. Consequently100% of the source term is expected to reach the confinement air.

Confinement Building A negative pressure is maintained in the confinement building so that all of the air that exits the buiding will exit through a stack. If an airborne RAM release is detected, the Emergency Air Handling System is activated, and the airflow is directed through an emergency filter prior to reaching the stack.

During facility re

-licensing, the volume of the confinement building was determined to be approximately 203,695 cubic feet. The volume of the pool structure and water was determined to be 21,740 cubic feet, leaving 181,955 cubic feet of open space. The control room takes up about 3,612 cubic feet of this space. Converting the free volume of the confinement room to cubic centimeters:

4 3 9 3 3 3 3 3 10 15.5 54.2 12 1 181955 cm X in cm ft in ft Concentration of RAM in the Confinement Air If we assume that the quantity of RAM that reaches the confinement air is spread uniformly throughout confinement, the concentration of each nuclide in the confinement building air would be: 9 cm 33 Therefore, the average concentration of each of the major nuclides would be:

Confinement AirConfinement AirConfinement AirActivityConcentrationConcentration(Ci)(Ci / cc)(Ci / cc)I-1311.57E+003.05E-103.05E-04I-1322.34E+004.55E-104.55E-04I-1333.84E+007.45E-107.45E-04I-1344.08E+007.91E-107.91E-04I-1353.63E+007.04E-107.04E-04Kr-85m7.55E-011.47E-101.47E-04Kr-851.62E-013.14E-113.14E-05Kr-871.35E+002.61E-102.61E-04Kr-882.07E+004.01E-104.01E-04Xe-133m1.07E-012.08E-112.08E-05Xe-1333.84E+007.46E-107.46E-04Xe-135m5.96E-011.16E-101.16E-04Xe-1353.81E+007.41E-107.41E-04Confinement Activity Concentration Emergency Filter

1. When the Emergency Air Handling System is activated, all of the air from the confinement room is exhausted through an emergency filter. The emergency filter consists of:

A. Roughing Filter B. HEPA Filter C. Charcoal Filter D. HEPA Filter

2. The proposed Technical Specifications associated with the Emergency Filter efficiency are:

5 3.5.2.3 The emergency filter shall be at least 99% efficient at removing iodine. 3.5.2.4 The Emergency Filter System Exhaust Absolute Filter shall be certified by the manufacturer to have a minimum efficiency of 99.97% for removing 0.3 micron diameter particulates.

3. Of the iodine that reaches the emergency filter, only the non-organic iodine is adsorbed by the charcoal filter. The organic iodine is not adsorbed.

4. The relative amounts of organic and non

-organic iodine are:

43% Organic Iodine 57% Non-Organic Iodine

5. Therefore, the concentration of non

-organic iodine in the confinement room that will reach the stack is:

(1%)(Confinement Concentration)

= (0.01)(Confinement Concentration)

6. The noble gases are unaffected by the HEPA filters, but are slowed by the charcoal filter. We will assume that all of the noble gases are released to the stack.

7. Overall: ConcentrationConcentrationEmergency FilterConfinement Airof Organicof Non-OrganicReleaseConcentrationIodineIodineConcentration (Ci / cc)(Ci / cc)(Ci / cc)(Ci / cc)I-1313.05E-041.31E-041.74E-041.33E-04I-1324.55E-041.96E-042.59E-041.98E-04I-1337.45E-043.20E-044.25E-043.25E-04I-1347.91E-043.40E-044.51E-043.45E-04I-1357.04E-043.03E-044.01E-043.07E-04Kr-85m1.47E-041.47E-04Kr-853.14E-053.14E-05Kr-872.61E-042.61E-04Kr-884.01E-044.01E-04Xe-133m2.08E-052.08E-05Xe-1337.46E-047.46E-04Xe-135m1.16E-041.16E-04Xe-1357.41E-047.41E-04Emergency Filter Release Concentrations

6 Stack Radioactive Material Release Rate

1. The dispersion calculations use radioactive material release rates, rather than activity concentrations.

2. The rate at which RAM is exhausted from the stack is equivalent to the rate at which it is exhausted from the emergency filter.

3. The higher the filter exhaust flow rate, the higher the RAM release rate from the stack. 4. Technical Specification 3.5.2.2 limits flow through the emergency filter to a maximum of 1500 cfm.

s cm X s in cm ft in ft10 08.7 60 min 54.2 12 min 1500 3 5 3 3 3 3 3

5. Therefore, the RAM release rate from the stack is:

s Ci s cmFlowrateExhaustFilterEmergency cm CiionConcentratExhaustFilterEmergency3 3

6. Overall: InitialStackStackRAM ReleaseConcentrationRate (Ci / cc)(Ci / cc)I-1311.33E-049.42E+01I-1321.98E-041.40E+02I-1333.25E-042.30E+02I-1343.45E-042.44E+02I-1353.07E-042.17E+02Kr-85m1.47E-041.04E+02Kr-853.14E-052.22E+01Kr-872.61E-041.85E+02Kr-884.01E-042.84E+02Xe-133m2.08E-051.47E+01Xe-1337.46E-045.28E+02Xe-135m1.16E-048.19E+01Xe-1357.41E-045.24E+02Stack RAM Release Rate

7 Atmospheric Dispersion

1. Air Turbulance Conditions A. Non-Fumigation Conditions Atmospheric stability is a measure of the turbulence in the plume, and it affects the rate of the dispersion of the plume. The more turbulent the air is, the greater the dispersion rate. There are six classifications of atmospheric stability, ranging from Pasquill Type A through Pasquill Type F, in which A is extremely unstable, and F is moderately stable. While this suggests that Pasquill Type F is conservative because it minimizes the dispersion rate and maximizes the airborne RAM concentrations at ground level, it is not necessarily the most conservative from the standpoint of the distance at which the plume reaches ground level.

B. Fumigation Conditions Fumigation is a condition in which there is an air inversion above the stack release which forces the plume to stay below the inversion. As a result, under fumigation conditions, the plume reaches the ground level at distances that are much shorter than what occurs under non

-fumigation conditions. NRC Regulatory Guide 1.145 Section 2.1.2.b indicates that for coastal sites that are located less than 3.2 kilometers from a large body of water, fumigation conditions should be assumed to exist.

C. Conditions Under Consideration Since the stack is approximately 150 meters from the Narragansett Bay, fumigation conditions were considered to be the predominant condition.

2. Dispersion Equations A. Atmoshperic dispersion calculations estimate the concentration of some material in air for a given release rate, under specified atmospheric conditions, at some distance away from the source. A Gaussian Straight Line Plume Model is used.

8 B. Fumigation Equation Section 1.3.2.b of NRC Regulatory Guide 1.145 (November 1982 Rev. 1) indicates that the equation for stack releases under fumigation conditions is:

e he y h u Q 21)2 (1 C. The factors for this equations is:

1. 2. 3. y is the horizontal dispersion coefficient (Distance)

4. z is the vertical dispersion coefficient (Distance)

5. h s is the stack height above the plant grade (Distance)

6. h t is the maximum terrain height above plant grade between the release point, and the point of interest (Distance)

7. h e is the effective stack height = h s - h t with h e = 0 if h t> h s (Distance)

8. uhe is the average wind speed of the fumigation layer at the effective 9 9. x is the downwind distance (Distance)

10. y is the horizontal distance at right angles to the plume centerline (Distance)

11. z is the height above the ground (Distance)

3. Stack Height The release is at the level of the stack (h s = 115 ft), with no significant change in terrain height between the release point and the site boundary (h t = 0), so the effective stack height is:

h e = h s - h t = 35m = 0 = 115 ft

= 35.052 m

4. Wind Direction Wind direction is assumed to be constant, As a result, all of the concentration of RAM will be along one line of direction, rather than dispersed across more than one direction. Consequently, this assumption is conservative.

5. Wind Speed The wind speed is assumed to be one meter per second. Higher wind speeds increase dilution because the RAM released per unit time is added to a larger volume of air passing by the release point. Consequently, this assumption is conservative.

6. Coordinates of Interest The dispersion coefficents are quantitative measures of how much the plume spreads out in the horizontal (y) and vertical (z) directions at some given distance (x) down wind of the release point. The material concentration in the plume as a function of distance from the plume centerline is a Gaussian distribution, with maximum concentration at the centerline. The dispersion coeficients are the standard deviations y distance from the centerline in the y

- z distance from the centerline in the z

- direction. For this analysis, the y and z values are taken to be zero so that the concentrations calculated will be associated with the centerline of the plume, and therefore will be the most conservative.

The distance between the confinement stack and the site boundary is 50 meters.

RINSC has the authority to prevent the public from entering this boundary.

10 The facility sits on the Bay Campus of the University of Rhode Island. There are residential areas to the north and south of the campus. To the west of the campus, woods and businesses abut the campus. To the northwest along South Ferry Road, there are residences as well. Using Google Maps to estimate the distances between the stack release point, and the residences to the north, nothwest, and south, the nearest residence was determined to be 500 meters from the stack:

Distance to Nearest Residence on South Ferry Road Distance to Nearest Residence in Saounderstown

11 Disatance to Nearest Residence in Bonnet Shores

Therefore the closest residence is 1600 feet from the stack:

The maximum concentration point occurs whenNeed Reference

z)2 = (h e)2 = 2/ From this, the maximum concentration point is the x distance from the stack that z that was calculated.

In addition to calculating where the maximum concentration point occurs, numerical methods were used to verify that it occurs where it is predicted to occur.

12 Consequently, the three points down wind of the stack that we are interested in knowing the RAM concentrations at ground level are:

1. Site Boundary (x = 50 meters)

2. Nearest Residence (x = 500 meters)

3. Maximum concentration point The dispersion coefficients take these distances into account. The dispersion coefficient curves given in the US Atomic Energy Commission's "Meteorology and Atomic Energy, 1968", pp. 102

- 103 are:

13 14 15 7. NRC Regulatory Guide 1.145 section 1.3.2.b provides the dispersion equation for fumigation conditions, and indicates that:

A. e he y h u Q 21)2 (1 B.

the initial conservative assumption was made that the wind speed is u = 1

C. y is determined under air turbulent conditions of Pasquill F. 1. The Site Boundary distance from the stack is 50 meters.

2. y dispersion coefficient at 50 meters is:

y is at 50 meters for the Pasquill F y vs. x graph, two data points are:

x 1 = 100 m y 1 = 4 m x 2 = 200 m y 2 = 8 m The slope of the line is:

= ( )( ) = ( )( ) = = 0.04 The point

- slope form of the line is:

(y 2 - y 1) = m(x 2 - x 1)

The y - intercept occurs at point (0,b):

(y 2 - b) = m(x 2 - 0)

(y 2 - b) = mx 2 y 2 - mx 2 = b b = y 2 - mx 2 b = (8 m)

- (0.04)(200 m) = 0.0 m

16 Consequently, the general equation is:

y = mx + b y = (0.04) x + 0.0 m

y is: y = y = (0.016)(50 m) + 0.08 m = 2.0 m

8. Consequently, the values of each of the factors in the fumigation dispersion equation are: h e = 35.052 m uhe y = 2.0 m

9. Plugging these values into the non

-fumigation dispersion equation:

)052.35 ()1 ()2 ()2 (1)2 (1 21 21 m s m m h u Q e he y -3 3 Converting the volume to units of cm 3: Q -3 33 -9 3

10. Methodology for Determining Concentrations at the Site Boundary, Nearest Residiential, and Maximum Concentration Points A. In order to get a sense of where the maximum concentration point is, dispersion coefficients were determined for distances ranging from the 50 meter site boundary point, to 10,000 meters out from the stack, including the 500 meter residential point.

B. f these distances.

C. Isotope concentrations were calculated for each of these distances, and the distance with the highest concentration data was highlighted.

D. A second set of dispersion coefficients were determined for distances at smaller increments around the point of maximum concentration found in the first set of data, in order to get a more precise location.

17 E.

F. Isotope concentrations were calculated for each of these new distances, and the distance with the highest concentration data was highlighted. The distance associated with these concentrations is the maximum concentration point.

18 12. Fumigation Results StackSite BoundaryNearest ResidenceRAM Release 50 m 200 m 500 m 1000 m 2000 m 5000 m 10000 m=3.141593RateConcentrationConcentrationConcentrationConcentrationConcentrationConcentrationConcentration (Ci / s)(Ci / cc)(Ci / cc)(Ci / cc)(Ci / cc)(Ci / cc)(Ci / cc)(Ci / cc)=6.283185I-1319.42E+015.37E-071.32E-075.37E-082.64E-081.51E-086.69E-093.86E-09I-1321.40E+028.00E-071.97E-078.00E-083.93E-082.25E-089.97E-095.76E-09=2.506628I-1332.30E+021.31E-063.22E-071.31E-076.43E-083.68E-081.63E-089.42E-09I-1342.44E+021.39E-063.42E-071.39E-076.83E-083.91E-081.73E-081.00E-08h(s)=115 ft=35.052 mI-1352.17E+021.24E-063.04E-071.24E-076.08E-083.48E-081.54E-088.91E-09Kr-85m1.04E+025.92E-071.45E-075.92E-082.91E-081.66E-087.37E-094.25E-09h(t)=0 ft=0 mKr-852.22E+011.27E-073.11E-081.27E-086.23E-093.56E-091.58E-099.12E-10Kr-871.85E+021.05E-062.59E-071.05E-075.18E-082.96E-081.31E-087.58E-09h(e)=115 ft=35.052 mKr-882.84E+021.62E-063.98E-071.62E-077.95E-084.54E-082.02E-081.16E-08Xe-133m1.47E+018.41E-082.06E-088.41E-094.13E-092.36E-091.05E-096.05E-10(y)=6 mXe-1335.28E+023.01E-067.40E-073.01E-071.48E-078.45E-083.75E-082.17E-08Xe-135m8.19E+014.67E-071.15E-074.67E-082.29E-081.31E-085.82E-093.36E-09U(he)=1m/sXe-1355.24E+022.99E-067.34E-072.99E-071.47E-078.39E-083.72E-082.15E-08Paquill 50 m 200 m 500 m 1000 m 2000 m 5000 m 10000 m/Q=1.90E-03s/m^3=1.9E-09s/cm^3 FX/QX/QX/QX/QX/QX/QX/Q(s / cc)(s / cc)(s / cc)(s / cc)(s / cc)(s / cc)(s / cc)2 8 20 40 70 160 2805.7E-091.4E-095.7E-102.8E-101.6E-107.1E-114.1E-11h(e)^2=m^2(z)^2=m^2StackRAM Release 50 m 100 m 150 m 200 m 250 m 300 m 350 m 400 m 500 m(z)=mRateConcentrationConcentrationConcentrationConcentrationConcentrationConcentrationConcentrationConcentrationConcentration(Ci / s)(Ci / cc)(Ci / cc)(Ci / cc)(Ci / cc)(Ci / cc)(Ci / cc)(Ci / cc)(Ci / cc)(Ci / cc)x[(z)=25]mI-1319.42E+015.37E-072.64E-071.79E-071.32E-070.00E+000.00E+000.00E+000.00E+000.00E+00I-1321.40E+028.00E-073.93E-072.67E-071.97E-070.00E+000.00E+000.00E+000.00E+000.00E+00I-1332.30E+021.31E-066.43E-074.37E-073.22E-070.00E+000.00E+000.00E+000.00E+000.00E+00I-1342.44E+021.39E-066.83E-074.64E-073.42E-070.00E+000.00E+000.00E+000.00E+000.00E+00I-1352.17E+021.24E-066.08E-074.13E-073.04E-070.00E+000.00E+000.00E+000.00E+000.00E+00Kr-85m1.04E+025.92E-072.91E-071.97E-071.45E-070.00E+000.00E+000.00E+000.00E+000.00E+00 x1=100 mKr-852.22E+011.27E-076.23E-084.23E-083.11E-080.00E+000.00E+000.00E+000.00E+000.00E+00 x2=200 mKr-871.85E+021.05E-065.18E-073.51E-072.59E-070.00E+000.00E+000.00E+000.00E+000.00E+00=4 mKr-882.84E+021.62E-067.95E-075.40E-073.98E-070.00E+000.00E+000.00E+000.00E+000.00E+00=8 mXe-133m1.47E+018.41E-084.13E-082.80E-082.06E-080.00E+000.00E+000.00E+000.00E+000.00E+00Xe-1335.28E+023.01E-061.48E-061.00E-067.40E-070.00E+000.00E+000.00E+000.00E+000.00E+00 m=0.04Xe-135m8.19E+014.67E-072.29E-071.56E-071.15E-070.00E+000.00E+000.00E+000.00E+000.00E+00 b=0Xe-1355.24E+022.99E-061.47E-069.96E-077.34E-070.00E+000.00E+000.00E+000.00E+000.00E+00=2Pasquill 50 m 100 m 150 m 200 m 250 m 300 m 350 m 400 m 500 m x1=100 m FX/QX/QX/QX/QX/QX/QX/QX/QX/Q x2=200 m(s / cc)(s / cc)(s / cc)(s / cc)(s / cc)(s / cc)(s / cc)(s / cc)(s / cc)=2.4 m=4 m2 4 6 8 m=0.016 b=0.85.7E-092.8E-091.9E-091.4E-09=1.6Atmospheric Dispersion CalculatorCalculated Maximum Concentration Point 19 13. RAM Concenterations at Points of Interest Site Boundary andNearestMaximum Concentration PointResidenceConcentrationConcentration (Ci / cc)(Ci / cc)I-1315.37E-075.37E-08I-1328.00E-078.00E-08I-1331.31E-061.31E-07I-1341.39E-061.39E-07I-1351.24E-061.24E-07Kr-85m5.92E-075.92E-08Kr-851.27E-071.27E-08Kr-871.05E-061.05E-07Kr-881.62E-061.62E-07Xe-133m8.41E-088.41E-09Xe-1333.01E-063.01E-07Xe-135m4.67E-074.67E-08Xe-1352.99E-062.99E-07RAM Concentrations at Points of Interest Dose Limits

1. Dose Calculation Background Information A. Health effects of radiation dose are separated into two categories:

1. Stochastic Effects

- These effects are probabilistic, and are due to random ionization events. Consequently, there is no threshold for these effects, and the probability of occurrence is proportional to the dose received. Cancer is an example of these types of effects.

2. Non-Stochastic Effects

- These effects depend on the amount of dose received beyond a minimum threshold, and the amount of damage depends on the magnatude of the dose. Skin erythmia is an example of a non-stochastic effect.

B. The objective of dose limits are to minimize the risk of stochastic effects, and to prevent the occurrence of non

-stochastic effects. The dose limits have been designed to be independent of whether or not the radiation dose is uniform or non

-uniform. This is achieved by having "effective dose" limits in which the "effective dose" takes into consideration the risk due to the irradiation of each individual organ 20 and equates it to the risk associated with a uniform irradiation of the whole body.

2. Definitions A. Allowable Limit on Intake (ALI)

- This is the amoung of RAM taken into the body via ingestion or inhalation that would lead to a committed effective dose equivalent of 5 Rem, or 50 Rem to any individual tissue or organ.

B. Derived Air Concentration (DAC)

- This is the concentration of a 4 cm 3 per minute for one working year (2000 hours0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br />) would result in reaching the ALI. Therefore, as an example, I

-131 has a D-8 3 and Ci Ci hr hr cm X cm Ci X ALI 50 48 1 2000 min 60 min 10 2 10 2 3 4 3 8

This means that if the reference man were to breath in the DAC for 2000 hours0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br />, at a rate of 2 x 10 4 uptake equivalent to the ALI.

C. Derived Air Concentration

- Hour (DAC

- Hour) -This is the product of the concentration of RAM in the air expressed as a fraction or multiple of the DAC, and the exposure time expressed in hours.

D. Absorbed Dose (D)

- This is a measure of the radiation energy that is absorbed per unit mass of material of interest.

E. Dose Equivalent (H)

- This is the product of the absorbed dose in tissue, quality factor (Q), and all other necessary modifying factors at the location of interest. The units of dose equivalent are the rem and sievert (Sv). In general:

H = DQ F. Quality Factor (Q)

- This is a regulatoraly defined factor to account for the fact that the type and energy of the incident radiation has an effect on the amount of biological damage that is produced per unit of absorbed energy (absorbed dose).

21 G. Tissue Dose Equivalent (H T) - This is the dose equivalent to a specific tissue or organ due to external sources.

H. Committed Dose Equivalent (HT,50) - This is the dose equivalent to organs or tissues of reference (T) that will be received from a single intake of radioactive material by an individual that will be accumulated over the 50

-year period following the intake.

I. Effective Dose Equivalent (H E) - This equates the risk of a non

-uniform external dose, or internal dose to the risk associated with a dose that is distributed uniformly over the whole body. A regulatoraly defined weighting factor (W T) is used for each organ, and the overall effective dose equivalent is

H E T H T This is the sum of the products of the dose equivalent to the organ or tissue (H T) and the weighting factors (W T) applicable to each of the body organs or tissues that are irradiated (H E T H T). J. Committed Effective Dose Equivalent (H E,50) - This is the effective dose equivalent accumulated over a 50 year period as a result of a single intake of radioactive material. In general:

HE,50 T HT,50 This is the sum of the products of the weighting factors applicable to each of the body organs or tissues that are irradiated and the committed dose equivalent to these organs or tissues (HE,50 = T HT,50).

K. Deep Dose Equivalent (DDE)

- This is the whole body dose at a depth of 1 cm due to an external exposure.

L. Total Effective Dose Equivalent (TEDE)

- This is the sum of the DDE due to an external dose, and the CEDE due to an internal dose from an intake of radioactive material. In general:

TEDE = DDE + CEDE

3. Regulatory Limits10 CFR 20 A. Occupational Dose Limits

1. yr [10 CFR 20.1201(a)(1)(i)]

2.

CFR 20.1201(a)(1)(ii)]

22 3. The DAC and ALI may be used to determine the individual's dose and to demonstrate compliance with dose limits. [10 CFR 20.1201(d)]

4. If the only intake of radionuclides is by inhalation, the total effective dose equivalent limit is not exceeded if the sum of the deep-dose equivalent divided by the total effective dose equivalent limit, and one of the following, does not exceed unity [10 CFR 20.1202(b)]

A. The sum of the fractions of the inhalation ALI for each radionuclide, or B. The total number of derived air concentration

-hours (DAC-hours) for all radionuclides divided by 2,000, or C. The sum of the calculated committed effective dos e equivalents to all significantly irradiated 1 organs or tissues (T) calculated from bioassay data using appropriate biological models and expressed as a fraction of the annual limit.

5. If the identity and concentration of each radionuclide in a mixture are known, the fraction of the DAC applicable to the mixture for use in calculating DAC

-hours must be either [10 CFR 20.1204(e)]

A. The sum of the ratios of the concentration to the appropriate DAC value (e.g., D, W, Y) from appendix B to part 20 for each radionuclide in the mixture; or B. The ratio of the total concentration for all radionuclides in the mixture to the most restrictive DAC value for any radionuclide in the mixture.

6. In order to calculate the committed effective dose equivalent, the licensee may assume that the inhalation of one ALI, or an exposure of 2,000 DAC

-hours, results in a committed effective dose equivalent of 5 rems (0.05 Sv) for radionuclides that have their ALIs or DACs based on the committed effective dose equivalent. [10 CFR 20.1204(h)(1)]

7. When the ALI (and the associated DAC) is determined by the nonstochastic organ dose limit of 50 rems (0.5 Sv), the intake of radionuclides that would result in a committed effective dose equivalent of 5 rems (0.05 Sv) (the stochastic ALI) is listed in parentheses in table 1 of appendix B to part 20. In this case, the licensee may, as a simplifying assumption, use the stochastic ALIs to determine committed effective dose equivalent. However, if the licensee uses the stochastic ALIs, 23 the licensee must also demonstrate that the limit in § 20.1201(a)(1)(ii) is met. [10 CFR 20.1204(h)(2)]

B. Dose Limits for Individual Members of the Public

1. 2. A licensee shall show compliance with the annual dose limit in

§ 20.1301 by [10 CFR 20.1302(b)]

A. Demonstrating by measurement or calculation that the total effective dose equivalent to the individual likely to receive the highest dose from the licensed operation does not exceed the annual dose limit or B. Demonstrating that:

1. The annual average concentrations of radioactive material released in gaseous and liquid effluents at the boundary of the unrestricted area do not exceed the values specified in table 2 of appendix B to part 20; and 2. If an individual were continuously present in an unrestricted area, the dose from external sources would not exceed 0.002 rem (0.02 mSv) in an hour and 0.05 rem (0.5 mSv) in a year.

4. External Immersion Dose vs. Internal Dose For the accidents involving fissionable material we are concerned about the doses that individuals will recieve due to airborne radioactive materials. The airborne RAM that is released in these types of accidents consist of halogens, such as iodine, and noble gases, such as xenon and krypton.

When halogens are inhaled, part of what is inhaled is taken up and incorporated into the body. Consequently, these isotopes cause a committed internal dose.

Noble gases are inert, so when they are inhaled, they are not taken up and incorporated into the body. Consequently, these isotopes cause an external immersion dose and do not contribute to an internal dose.

The principle halogen that is released from fission as an airborne RAM source is iodine. When iodine is uptaken into the body, it concentrates in the thyroid.

As a result, the internal dose associated with a fissionable experiment failure would be the Committed Dose Equivalent (HT,50) to the thyroid due to iodine. A regulatoraly defined weighting factor (W T) is used to equate the risk of a non-uniform external dose, or internal dose to the risk associated with a dose 24 that is distributed uniformly over the whole body. The product of the Committed Dose Equivalent and the weighting factor is the Committed Effective Dose Equivalent accumulated over a 50 year period as a result of a single intake of radioactive material (HE,50).

During a fissionable experiment failure , the principle noble gases that are released as airborne RAM sources are krypton and xenon. These isotopes are the are the sources for the external immersion dose. As a result, the external immersion dose that is associated with a fuel failure accident is the Deep Dose Equivalent (DDE) to the whole body due to the iodine, krypton, and xenon isotopes.

The Total Effective Dose Equivalent (TEDE) is the sum of the Deep Dose Equivalent (DDE), and the Committed Effective Dose Equivalent (HE,50).

5. What We Must Show A. Therefore, based on the regulations, we must show that:

1. The occupational doses to individuals inside confinement are no greater than:

A. TEDE = 5 rem B.

2. The doses to the public at the site boundary, maximum concentration point, and nearest residence are no greater than:

A. Dose Calculation Methodology

1. Use of the DAC to Determine the Committed Dose Equivalent to the Thyroid (CDE) A. The ALI and DAC for any given nuclide can be found in 10 CFR 20 Appendix B. For I

-131, the inhalation values for occupational exposure are given to be:

1. ALI = 50 -131 will lead to a CEDE of 5 Rem, or 50 Rem to any individual tissue or organ. Since iodine concentrates in the thyroid, the ALI is based on a dose of 50 Rem to the thyroid.

2. -8 cm 3 25 This means that if an individual inhales concentration of 10-8 cm 3 I-4 cm 3 per minute for 2000 hours0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br />, they would intake enough of the radionuclide to receive a CEDE of 5 Rem whole body, or 50 Rem to any individual tissue or organ:

B. If an individual is immersed in an air concentration equivalent to one DAC, the average dose rate that they would be receiving would be:

1. Individual Tissue or Organ (in this case Thyroid):

hrDAC mrem hr rem25 2000 50 C. Since this is the dose rate that is associated with an airborne RAM concentration of one DAC, we can relate the dose rate associated with being immersed in an airborne RAM concentration of one DAC by:

25 =25 /

D. We can express the concentration of any RAM in air as a fraction or multiple of the DAC:

DAC Fraction (Multiple) = (Air Concentr E. Therefore, if we had a concentration of 3.05 -4cm 3 of I-131 in the confinement air, the DAC fraction (multiple) if the occupational -8cm 3 would be: DAC Fraction (Multiple)

= 3.05 10 131 2 10 / = 15250 DAC F. For the iodines, the committed dose to the thyroid is also dependent on the amount of time that the individual is immersed. If an individual were only in the concentration of iodine for 5 minutes (0.083 hr), then the DAC fraction can be reduced:

Immersion DAC = (DAC)(Immersion Time)

Immersion DAC = (15250 DAC)(0.083 hr) = 1266 DAC - hr 26 G. If we know the concentration of RAM in air as a fraction or multiple of the DAC, then we can determine the committed dose rate that that an individual immersed in the air would recieve. Continuing with the

I-131 example:

mrem hrDAC hrDAC mrem 31650 1 1266 25 H. If there is more than one nuclide in the air with the same dose rate associated with exposure (either whole body or individual organ), then the DAC fractions can be added together before determining the dose rate. Consider:

1. Suppose that the air has a concentration of 3.05

-4cm 3 of I-131, and 4.55

-4cm 3 of I-132 in it. The DAC fractions are:

Where the DAC is defined in 10 CFR 20 for each isotope

2. For I-131 the DAC fraction has been previously calculated to be 15250 DAC. 3. For I--6cm 3, the DAC fraction is:

(4.55 -4cm 3-6cm 3) = 152 DAC 4. Therefore the total DAC fraction is:

Total DAC Fraction = 15250 DAC + 152 DAC = 15402 DAC 6. Both of these DACs are based on a committed thyroid dose of 50 rem per year, which means that the dose rate associated with - hr. 7. Therefore the committed dose to the thyroid for an individual that is immersed for 5 minutes in air with a concentration of

3.05 -4cm 3 of I-131 and 4.55 -4cm 3 of I-132 would be:

mrem hrDAC hrDAC mrem 31959 1 083.0 1 15402 25 27 2. Use of the DAC to Determine Deep Dose Equivalent (DDE)

A. The DAC for any given nuclide can be found in 10 CFR 20 Appendix B. For Kr

-85, the inhalation value of the DAC for occupational exposure are given to be:

-4 cm 3 This means that if an individual is immersed in a concentration of 10-4 cm 3 Kr-85 for 2000 hours0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br />, they would receive a DDE of 5 Rem whole body.

B. If and individual is immersed in an air concentration equivalent to one DAC, the average dose rate that they would be receiving would be:

Whole Body:

hr mrem hr rem5.2)2000 (5 C. Since this is the dose rate that is associated with an airborne RAM concentration of one DAC, we can relate the dose rate associated with being immersed in an airborne RAM concentration of one DAC by:

2.5 =2.5 / D. We can express the concentration of any RAM in air as a fraction or multiple of the DAC:

DAC Fraction (Multiple) = (A E. Therefore, if we had a concentration of 3.14

-5cm 3 of Kr-85 in the confinement air, the DAC fraction (multiple) if the occupational DAC were -4cm 3 would be: DAC Fraction (Multiple)

= (Air Concentration)

= 3.14 10 85 1 10 /

= 0.314 DAC F. If we know the concentration of RAM in air as a fraction or multiple of the DAC, then we can determine the dose rate that that an individual 28 immersed in the air would recieve. Continuing with the Kr

-85 example: hr mremDAC hrDAC mrem785.0 1 314.0 5.2 G. For a mixture of airborne radionuclides, the total dose rate can be determined either by summing the individual DAC fractions and multiplying the sum by the dose rate per DAC

- hr: )(1 5.2 hr mremRateDoseTotalFractionsDAC hrDAC mrem Or by finding the dose rate associated with each nuclide and summing the individual dose rates to get the total dose rate:

2.5 1 = (/) H. Consider: 1. Suppose that the air has a concentration of 3.14

-5cm 3 of Kr-85, a nd 1.47 -4cm 3 of Kr-85m in it. The DAC fractions are:

Where the DAC is defined in 10 CFR 20 for each isotope

2. For Kr-85 the DAC fraction has been previously calculated to be 0.314 DAC.

3. For Kr--5cm 3, the DAC fraction is:

(1.47 -4cm 3-5cm 3) = 7.35 DAC

4. Therefore the total DAC fraction is:

Total DAC Fraction = 0.314 DAC + 7.35 DAC =

7.66 DAC

5. Therefore the dose rate associated with the deep dose equivalent is:

29 hr mremDAC hrDAC mrem2.19 1 66.7 5.2 Halogen Dose Calculations for Personnel Inside Confinement

1. Confinement Committed Dose to the Thyroid (CDE) A. Halogens are an inhalation hazard because they are absorbed into the body. The halogen of interest in the case of a fuel failure is iodine.

Iodine concentrates in the thyroid. Consequently, the DAC for each isotope of Iodine is based on the amount of isotope that will result in a 50 rem dose to the thyroid over a 2000 hour0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br /> year. We have calculated that an individual immersed in air with a concentration of RAM in it equivalent to one DAC would lead to an internal dose rate of 25 mrem e thyroid.

10 CFR Part 20 Appendix B Table 1 Column 3 provides the occupational DACs for the isotopes of interest.

B. Facility evacuation drills show that in the event of an evacuation, the confinement building can be evacuated within 5 minutes. Thererfore the projected dose from the gas release for individuals inside confinement when the fuel failure occurs is:

)(min 60 1 min 5 1 25 mremCDE hrFractionDAC hrDAC mrem

C. For the isotopes of interest:

NuclideConfinementOccupational DACImmersionCommitted DoseConcentration DACFraction DACEquivalent(microCi / cc)(microCi / cc)(DAC-hr)(mrem)I-1313.05E-042.00E-081.53E+041.27E+033.18E+04I-1324.55E-043.00E-061.52E+021.26E+013.16E+02I-1337.45E-041.00E-077.45E+036.21E+021.55E+04I-1347.91E-042.00E-053.96E+013.30E+008.24E+01I-1357.04E-047.00E-071.01E+038.38E+012.10E+03Confinement Internal Dose

Therefore, if someone remains in confinement for five minutes, they will receive a committed does to the thyroide of:

4 mrem D. The committed effective dose equivalent (CEDE) is the product of the total CDE and a regulatorily defined weighting factor (W T) for the 30 organ of interest.

In this case, we are interested in the thyroid dose. 10 CFR Part 20.1003 provides the weighting factor for the thyroid:

W T = 0.03 E. Therefore the CEDE is:

4 mrem)(0.03) = 1494 mrem Noble Gas Dose Calculations for Personnel Inside Confinement

1. For the isotopes of interest, assuming an occupancy time of five minutes:

NuclideConfinementOccupational DACImmersionDeep DoseConcentration DACFraction DACEquivalent(microCi / cc)(microCi / cc)(DAC-hr)mremKr-85m1.47E-042.00E-057.33E+006.11E-011.53E+00Kr-853.14E-051.00E-043.14E-012.62E-026.54E-02Kr-872.61E-045.00E-065.22E+014.35E+001.09E+01Kr-884.01E-042.00E-062.01E+021.67E+014.18E+01Xe-133m2.08E-051.00E-042.08E-011.74E-024.34E-02Xe-1337.46E-041.00E-047.46E+006.22E-011.55E+00Xe-135m1.16E-049.00E-061.29E+011.07E+002.68E+00Xe-1357.41E-041.00E-057.41E+016.17E+001.54E+01Confinement Air External Dose Therefore, if someone remains in confinement for five minutes, they will receive a dose of: mrem Total Effective Dose Calculations for Personnel Inside Confinement

1. Total Effective Dose Equivalent (TEDE)

- This is the sum of the DDE due to an external dose, and the CEDE due to an internal dose from an intake of radioactive material. In general:

TEDE = DDE + CEDE

= 1494 mrem + 74 mrem = 1568 mrem

31 Dose Calculations for General Public at Site Boundary and Maximum Concentration Point

1. 10 CFR 20 Appendix B indicates that for offsite doses to the public due to airborne releases, values listed in Table 2 column 1 should be used. These concentrations correspond to an annual dose of 100 mrem.

2. Therefore, if an individual is immersed in an air concentration equivalent to one DAC, the average dose rate that they would be receiving would be:

hrDAC mrem hryearyearDAC mrem011.0 8760 100 3. Section 1.3 of NRC Regulatory Guide 1.145 (November 1982 Rev. 1) indicates that a conservative estimation of site boundary doses can be determined by it assuming that an individual spends two hours at the site boundary immediately following an accident.

4. For the isotopes of interest, assuming an occupancy time of two hours:

NuclideConcentrationPublic DACImmersionEffective DACFraction DACDose(microCi / cc)(microCi / cc)(DAC-hr)(mrem)I-1315.37E-072.00E-102.68E+035.37E+036.13E+01I-1328.00E-072.00E-084.00E+018.00E+019.14E-01I-1331.31E-061.00E-091.31E+032.62E+032.99E+01I-1341.39E-066.00E-082.32E+014.64E+015.29E-01I-1351.24E-066.00E-092.06E+024.13E+024.71E+00Kr-85m5.92E-071.00E-075.92E+001.18E+011.35E-01Kr-851.27E-077.00E-071.81E-013.62E-014.13E-03Kr-871.05E-062.00E-085.27E+011.05E+021.20E+00Kr-881.62E-069.00E-081.80E+013.60E+014.11E-01Xe-133m8.41E-086.00E-071.40E-012.80E-013.20E-03Xe-1333.01E-065.00E-076.02E+001.20E+011.37E-01Xe-135m4.67E-074.00E-081.17E+012.33E+012.67E-01Xe-1352.99E-067.00E-084.27E+018.54E+019.75E-01Site Boundary and Maximum Concentration Point Internal Dose

Therefore, if someone remains in at the site boundary, which is also the maximum concentration point for two hours, they will receive a total effective dose of: 100 mrem

32 Dose Calculations for General Public at Nearest Residence

1. For the isotopes of interest, assuming an occupancy time of two hours:

NuclideConcentrationPublic DACImmersionEffective DACFraction DACDose(microCi / cc)(microCi / cc)(DAC-hr)(mrem)I-1315.37E-082.00E-102.68E+025.37E+026.13E+00I-1328.00E-082.00E-084.00E+008.00E+009.14E-02I-1331.31E-071.00E-091.31E+022.62E+022.99E+00I-1341.39E-076.00E-082.32E+004.64E+005.29E-02I-1351.24E-076.00E-092.06E+014.13E+014.71E-01Kr-85m5.92E-081.00E-075.92E-011.18E+001.35E-02Kr-851.27E-087.00E-071.81E-023.62E-024.13E-04Kr-871.05E-072.00E-085.27E+001.05E+011.20E-01Kr-881.62E-079.00E-081.80E+003.60E+004.11E-02Xe-133m8.41E-096.00E-071.40E-022.80E-023.20E-04Xe-1333.01E-075.00E-076.02E-011.20E+001.37E-02Xe-135m4.67E-084.00E-081.17E+002.33E+002.67E-02Xe-1352.99E-077.00E-084.27E+008.54E+009.75E-02Dose at Nearest Residence Therefore, if someone remains in at the nearest residence for two hours, they will receive a total effective dose of:

Individual Effective Dose = 10 mrem Summary Confinement Dose4.98E+04mrem 50CEDE1.49E+03mremImmersion7.40E+01mremTEDE1.57E+03mrem 5100TEDE1.00E+02mrem 100TEDE1.00E+01mrem 100Dose SummaryDose LimitsOccupational LimitsGeneral Public LimitsNearest Residence Dose

33 Conclusion If we assume that an experiment with 0.0875 grams of fissionable material has been irradiated long enough for the fission products in it to be at saturation levels , and that all of the fission products are relased to confinement, 10 CFR 20 limits will still be met if it takes 5 minutes to evacuate confinement, and personnel down wind at the site boundary are located there for 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />.