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# UFD_BIOSPHERE¶

Specifies the Example Reference Biosphere (ERB) Model 1, which calculates annual dose to an individual drinking radioactive water from a well (IAEA 2003).

Under the SIMULATION block this process model is included by adding the UFD_BIOSPHERE block:

SIMULATION
SIMULATION_TYPE SUBSURFACE
PROCESS_MODELS
UFD_BIOSPHERE <name_string>
/
SUBSURFACE_FLOW flow
MODE GENERAL
/
SUBSURFACE_TRANSPORT transport
GLOBAL_IMPLICIT
/
/
END


where <name_string> gives a user-defined name for the process model.

## Required Cards:¶

UFD_BIOSPHERE
Opens the UFD_BIOSPHERE block. Must have a matching END line.

### ERB_1A/B block¶

ERB_1A or ERB_1B <name_string>
Opens the ERB Model block with either the ERB_1A model type or the ERB_1B model type. Any number of ERB Models blocks may be specified. ERB_1A is used for water that is extracted by a sink (well) in the simulation. ERB_1B is used to approximate dose from a hypothetical well not explicitly modeled.

ERB_1A block required cards:

REGION <string>

Specifies the REGION associated with the ERB_1A model, where <string> indicates the name of that region. This region must be associated with a SOURCE_SINK which is located at the screened portion of a pumping water well.

REGION well-45b

INDIVIDUAL_CONSUMPTION_RATE <double> <unit_string>

Specifies the water consumption rate in units of volume/time that the typical person drinks out of the contaminated well.

INDIVIDUAL_CONSUMPTION_RATE 3.4 L/day


Optional Cards:

If this card is included, then the ERB_1A model will consider both supported and unsupported radionuclides in the calculation of dose. Unsupported radionuclides are those which are not explicitly modeled in the simulation (e.g. as a source term or in transport) due to short half-lives, but are considered in a dose calculation.

ERB_1B block required cards:

REGION <string>

Specifies the REGION associated with the ERB_1B model, where <string> indicates the name of that region. This region must NOT be associated with a SOURCE_SINK. Rather, the region is the location of a potential pumping water well, at the screened portion of the well.

REGION potential-well-22c

INDIVIDUAL_CONSUMPTION_RATE <double> <unit_string>

Specifies the water consumption rate in units of volume/time that the typical person drinks out of the contaminated well.

INDIVIDUAL_CONSUMPTION_RATE 2.1 L/day

DILUTION_FACTOR <double>

Specifies a unitless dilution factor that accounts for the dilution of radionuclides at the location of the potential well. The dilution factor is the user-estimated volumetric ratio of discharged well water to captured plume water. This number should be larger than or equal to 1. A value of 1 implies no dilution (e.g., discharged well water = captured plume water).

DILUTION_FACTOR 4.3d0


Optional Cards:

If this card is included, then the ERB_1B model will consider both supported and unsupported radionuclides in the calculation of dose. Unsupported radionuclides are those which are not explicitly modeled in the simulation (e.g. as a source or in transport) due to short half-lives, but are considered in a dose calculation.

Examples of the ERB_1A/B blocks:

ERB_1A A_model1
REGION well
INDIVIDUAL_CONSUMPTION_RATE 5.d0 L/day
/
ERB_1B B_model1
REGION potential-well-22c
DILUTION_FACTOR 2.d0
INDIVIDUAL_CONSUMPTION_RATE 2.d0 L/day
/
ERB_1B B_model2
REGION potential-well-67f
DILUTION_FACTOR 1.d0
INDIVIDUAL_CONSUMPTION_RATE 3.d0 L/day
/


Opens the SUPPORTED_RADIONUCLIDES block which indicates which supported radionuclides are considered in the dose calculations. The following cards or sub-blocks are required:

Specifies a sub-block for each supported radionuclide, where <string> indicates the name of the supported radionuclide. The radionuclide must be included as either a primary or secondary species in the CHEMISTRY block.

RADIONUCLIDE Tc-99
...
/

ELEMENT_KD <double>

Specifies the elemental Kd value within the material where the screen portion of the well resides. The units can be given in L-water/kg-solid or kg-water/m3-bulk, as long as the units are consistent for all supported and unsupported radionuclides.

ELEMENT_KD 3.5d5

DECAY_RATE <double> <unit_string>

Specifies the decay rate of the supported radionuclide in units of [1/time].

DECAY_RATE 1.29d-13 1/sec

INGESTION_DOSE_COEF <double>

Specifies the ingestion dose coefficient for the supported radionuclide in units of Sv/Bq.

INGESTION_DOSE_COEF 1.d-9


Examples of a full SUPPORTED_RADIONUCLIDES block:

SUPPORTED_RADIONUCLIDES
ELEMENT_KD 3.5d5  # at screened part of well
DECAY_RATE 1.4d-11 1/sec
INGESTION_DOSE_COEF 2.8d-7 # Sv/Bq
/
ELEMENT_KD 4.2d5  # at screened part of well
DECAY_RATE 1.04d-12 1/sec
INGESTION_DOSE_COEF 1.1d-7 # Sv/Bq
/
/


The concentration [Bq/L] of an unsupported radionuclide in secular equilibrium with its supported parent is the product of the sorption enhancement factor of the unsupported radionuclide, the emanation factor of the unsupported radionuclide, and the concentration [Bq/L] of the supported parent.

Opens the UNSUPPORTED_RADIONUCLIDES block which indicates which unsupported radionuclides are considered in the dose calculations. These are only included in the calculation for the ERB models that contain the card INCLUDE_UNSUPPORTED_RADS. The following cards or sub-blocks are required:

Specifies a sub-block for each unsupported radionuclide, where <string> indicates the name of the unsupported radionuclide. The radionuclide should NOT be included as either a primary or secondary species in the CHEMISTRY block because it is unsupported.

RADIONUCLIDE Bi-210
...
/

ELEMENT_KD <double>

Specifies the elemental Kd value within the material where the screen portion of the well resides. The units can be given in L-water/kg-solid or kg-water/m3-bulk, as long as the units are consistent for all supported and unsupported radionuclides. Kd is needed to calculate the sorption enhancement factor for each unsupported radionuclide. The sorption enhancement factor is the ratio of the retardation factor of the supported parent to that of the unsupported radionuclide.

ELEMENT_KD 6.5d5

DECAY_RATE <double> <unit_string>

Specifies the decay rate of the unsupported radionuclide in units of [1/time].

DECAY_RATE 8.9d-11 1/sec

INGESTION_DOSE_COEF <double>

Specifies the ingestion dose coefficient for the unsupported radionuclide in units of Sv/Bq.

INGESTION_DOSE_COEF 1.d-7

EMANATION_FACTOR <double>

Specifies the optional emanation factor in the dose calculation for an unsupported radionuclide. The default value is 1.0 if this keyword is omitted.

EMANATION_FACTOR 0.4

SUPPORTED_PARENT <string>

Indicates the name of the unsupported radionuclide’s supported parent radionuclide. The supported parent must be included as a supported radionuclide in the SUPPORTED_RADIONUCLIDES block.

SUPPORTED_PARENT Pb-210


Example of a full UNSUPPORTED_RADIONUCLIDES block:

UNSUPPORTED_RADIONUCLIDES
ELEMENT_KD 3.5d5  # at screened part of well
DECAY_RATE 1.d-14 1/sec
SUPPORTED_PARENT tracerA
INGESTION_DOSE_COEF 1.d-10 # Sv/Bq
EMANATION_FACTOR 0.4d0
/
ELEMENT_KD 4.2d5  # at screened part of well
DECAY_RATE 1.d-10 1/sec
SUPPORTED_PARENT tracerA
INGESTION_DOSE_COEF 1.d-9 # Sv/Bq
/
ELEMENT_KD 2.2d8  # at screened part of well
DECAY_RATE 1.d-9 1/sec
SUPPORTED_PARENT tracerB
INGESTION_DOSE_COEF 1.d-8 # Sv/Bq
EMANATION_FACTOR 0.4d0
/
/


### Output Control¶

At each time step, the process model will add dose calculations to an output file named *.bio. The output includes the total dose from all supported and unsupported* radionuclides, the annual dose from each radionuclide, as well as the annual dose from each supported radionuclide and its unsupported descendents. The average concentration of each radionuclide in the region associated with each ERB model is also reported.

OUTPUT_START_TIME <double> <unit_string>

If this card is included, the dose calculations will not be printed to the output.bio file until after this point in the simulation time. The default start time is 0.d0 seconds (e.g. starting at the first time step).

OUTPUT_START_TIME 5.d0 yr


## Examples:¶

UFD_BIOSPHERE

ERB_1A A_model1
REGION well
INDIVIDUAL_CONSUMPTION_RATE 5.d0 L/day
/
ERB_1B B_model1
REGION ERB1B_tester1
DILUTION_FACTOR 1.d0
INDIVIDUAL_CONSUMPTION_RATE 2.d0 L/day
/
ERB_1B B_model2
REGION ERB1B_tester2
DILUTION_FACTOR 5.d0
INDIVIDUAL_CONSUMPTION_RATE 3.d0 L/day
/

ELEMENT_KD 3.5d5  # screened part of well
DECAY_RATE 1.29d-15 1/sec
INGESTION_DOSE_COEF 1.d-10 # Sv/Bq
/
ELEMENT_KD 4.2d5  # screened part of well
DECAY_RATE 1.29d-15 1/sec
INGESTION_DOSE_COEF 1.d-9 # Sv/Bq
/
/

ELEMENT_KD 3.5d5  # at screened part of well
DECAY_RATE 1.d-14 1/sec
SUPPORTED_PARENT tracerA
INGESTION_DOSE_COEF 1.d-10 # Sv/Bq
EMANATION_FACTOR 0.4d0
/
ELEMENT_KD 4.2d5  # at screened part of well
DECAY_RATE 1.d-10 1/sec
SUPPORTED_PARENT tracerA
INGESTION_DOSE_COEF 1.d-9 # Sv/Bq
/