Assessment of dose consequences based on postulated BDBA (beyond design basic accident) A-30MWt RSG-GAS after 30-year operation

An assessment of the consequences of radiation doses due to the BDBA (beyond design basic accident) on the RSG-GAS research reactor has been done. The assessment was carried out to evaluate the KNS (Serpong Nuclear Area) EPZ (emergency preparedness zone) site after the reactor was operational for 30 years. The RSG-GAS research reactor is a 30MWt multipurpose reactor.

Available online 14 August 2021

0149-1970/© 2021 The Authors Published by Elsevier Ltd This is an open access article under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ ).

Assessment of dose consequences based on postulated BDBA (beyond

design basic accident) A-30MWt RSG-GAS after 30-year operation

P.M Udiyani, M.B Setiawan*, M Subekti, S Kuntjoro, J.S Pane, E.P Hastuti, H Susiati

BATAN, Center for Nuclear Reactor Technology and Safety, Puspiptek Region Gd.80 Serpong, Tangerang Selatan, 15310, Indonesia

A R T I C L E I N F O

Keywords:

Dose

RSG-GAS

BDBA

Accident

EPZ

A B S T R A C T

An assessment of the consequences of radiation doses due to the BDBA (beyond design basic accident) on the RSG-GAS research reactor has been done The assessment was carried out to evaluate the KNS (Serpong Nuclear Area) EPZ (emergency preparedness zone) site after the reactor was operational for 30 years The RSG-GAS research reactor is a 30MWt multipurpose reactor It is the largest research reactor in Indonesia RSG-GAS was built in the KNS Area in the Puspiptek complex which was put into operation in 1987 Previous estima-tions of the radiological consequences were made on accidents which were postulated based on DBA condiestima-tions With the aging of the reactor, a study was carried out on the radiological consequences of the BDBA accident The ATWS (anticipated transient without scram) event caused the BDBA condition which resulted in the melted of 5 fuel bundles Source term is estimated based on an inventory of 5 melted fuel bundles, and fission products release through the reactor core, cooling system, reactor hall, and finally discharge to the environment through the reactor stack Radionuclide inventory is calculated by ORIGEN2.1 With the influence of weather, fission products are dispersed into the air and deposited to the surface of the soil on the site Weather and environmental data used are spatial analysis of ARC-GIS Consequences analysis was carried out in 16 wind direction sectors within a 5 km radius using PC-COSYMA The calculation results show the largest dose is reached in a radius below 500 m with the direction of the wind to the South The radiation dose is below the dose limits for the exclusion and beyond exclusion area Consequences of BDBA accident dose at RSG-GAS does not require countermeasure like sheltering, evacuation nor relocation

1 Introduction

The RSG-GAS research reactor was built in 1983 This research

reactor is located in the Serpong Nuclear Area (KNS) Puspiptek It

reached its first critical level in July 1987 In March 1992 the reactor

operated at a nominal power of 30 MW The permit to extend the

operation until 2030 was issued by Bapeten Indonesian nuclear

regu-latory body, on December 6, 2020

RSG-GAS is a pool type reactor designed as a medium power research

reactor (30 MW) It is located in the Center for Science and Technology

Research (PUSPIPTEK) Serpong, South Tangerang This site is located at

6◦21′40′′south latitude, 106◦39′57′′east longitude and about 60 m

above sea level The reactor site is surrounded by several villages and the

Cisadane river as the western boundary

Puspiptek area which has an area of 3.5 square kilometer It is

located in Setu village, Cisauk sub-district, Tangerang district, Banten

province The Puspiptek area is about 27 km southwest of the

metropolitan city of Jakarta, and the distance from the site to the sea area, namely the Java Sea, is about 36 km

The type of fuel is a plate with low uranium enrichment (19.75 %) In the year of 2005, its fuel - which was originally Uranium Oxide – was changed to Uranium Silicide (U3Si2–Al) The number of fuel elements in the reactor core is 40 fuel elements (FEs) and 8 control elements (CEs) (BATAN, 2019) Coolant and moderator of reactors is light water (H2O) with a Berylium reflector RSG-GAS is a multipurpose reactor used mainly for neutronical, thermohydraulic, reactor safety system, power reactor research, and radiation protection It is also used for the pro-duction of radioisotopes and silicon dopping, advanced material irra-diation and for Neutron Activation Analysis (NAA)

The operation of the RSG-GAS has the consequence of radioactive discharge into the environment Radioactive releases into the environ-ment from the operation of nuclear reactors occur under normal or abnormal operating conditions Radioactive releases through the reactor stack will spread in the atmosphere and deposited to the ground surface

* Corresponding author

E-mail address: setiawan@batan.go.id (M.B Setiawan)

Contents lists available at ScienceDirect Progress in Nuclear Energy

journal homepage: www.elsevier.com/locate/pnucene

https://doi.org/10.1016/j.pnucene.2021.103927

Received 21 January 2021; Received in revised form 25 June 2021; Accepted 9 August 2021

Progress in Nuclear Energy 140 (2021) 103927

With the influence of weather and local meteorological conditions, this

radioactive substance is spread and through various pathways of

expo-sure into the human body The Safety Analysis Report (SAR) document

from the RSG-GAS and the study of the radiological consequences of the

reactor operating in normal conditions and postulated DBA accidents

have been carried out by several researchers (Udiyani et al., 2018a;

Kuntjoro and Udiyani, 2005)

The results of the study of the consequences of normal conditions are

used as a basis for environmental monitoring of the KNS site While the

results of the study of the consequences of the accident are used as a

nuclear emergency in the KNS region In accordance with SAR and the

Bapeten regulatory body considerations, nuclear emergency zones

within the site and outside the site are monitored within a 5 km radius A

500 m exclusion zone is determined and emergency areas outside the

exclusion zone up to 5 km The determination of the emergency zone is

estimated based on the DBA accident postulation, which is an accident

resulting from the melting of a bundle of fuel elements The assumption

is that there has been an accident that is the damage of a set of fuel

el-ements (equal to 21 plates of the fuel element) The accident caused by a

blockage of the cooling channel These accidents resulted fission product

nuclides regardless of the cladding of fuel into the cooling system with a

particular faction Part of the nuclide is released from the cooling water/

reactor tank into the reactor chamber Finally a small portion of

radio-nuclides can be released from the reactor chamber into the atmosphere

(BATAN, 2019; Kuntjoro and Udiyani, 2005; Hastowo, 1996)

Since the accident of the Dai-ichi Fukushima reactor, the IAEA and

the regulatory body of the nuclear reactor owner re-review the safety of

existing reactors and those are not yet operated The review was carried

out by adding a study of radiation impacts to severe accidents or BDBA

(Arjun et al., 2014; Mehbooba et al., 2015; Raimond et al., 2013)

Learning from the Fukushima accident and the aging of the RSG-GAS

which is already 30 years old, a study of the radiological

conse-quences to be included in the SAR were done based on the BDBA

acci-dent Based on the dissertation of Hudi Hastowo (1996) (Hastowo,

1996), BDBA conditions are surrounded by reactor thermohydraulic

calculations based on the ATWS (Anticipated Transient Without Scram)

ATWS is triggered by the blockage of the coolant flow in the fuel The

simulation results obtained a state where 5 fuel bundles melt (BATAN,

2019; Hastowo, 1996) Based on these conditions the inventory and

source term of the BDBA accident are calculated With meteorological

influences and site environmental data within a 5 km radius, it can be

determined the activity of fission products that are dispersed in the

at-mosphere and deposited on the surface of the site With various

path-ways that are adapted to local data and conditions, receipt of doses and

emergency zoning can be estimated Calculation of inventory of fission

products in fuel or reactor core using ORIGEN 2.1 (Rahgoshay and

Hashemi-Tilehnoee, 2013; Obaidurrahman and Gupta, 2013; Setiawan

et al., 2020; Kuntjoro et al., 2019) Meteorology and environmental data

are processed with software for spatial analysis, ARC-GIS Estimation of

radiologic consequences in the environment using PC-Cosyma software

based on the atmospheric dispersion model (Udiyani et al., 2016;

Udiyani et al., 2018b; Cao et al., 2000; Udiyani et al., 2019; European

Commission, 1995)

2 Methodology

Study of the consequences of environmental and community has

based on radiology atmospheric disperse (Pirouzmand et al., 2015;

Birikorang et al., 2015; Abdelhady, 2013; Hirose, 2016) The calculation

mechanism starts from the calculation of fuel inventory, and source term

is calculated based on inventory data Fission products released to the

primary cooling water system through the reactor pool passes to the

reactor hall and reactor building It is assumed that fission products

release into the atmosphere as source term without going through stack

filters

Due to the influence of meteorology, the plume formed is dispersed

in the atmosphere, deposited on the ground surface, and through various pathways into the human body Zoning of nuclear emergencies is determined based on the receipt of public and environmental doses The methodological approach to calculating radiation consequences is shown in Fig 1

2.1 Radioactivity source term

The source term calculation is based on a BDBA accident that was simulated in the RSG-GAS The worst accident condition which was simulated in the reactor thermo-hydraulic calculation based on the ATWS condition which was triggered by the blockage of the coolant flow

in the fuel This condition causes 5 fuel elements to melt (Hastowo,

1996) Calculation of inventory of fission products on 5 melted fuels using ORIGEN 2.1 The calculation is done based on the neutral pa-rameters of the fuel Fuel material from U3Si2Al; Cladding material from AlMg3; Channel width is 2.55 mm; The number of U-235 per element of fuel is 250 g; Fuel dimensions (0.54 x 62.75 × 600 mm); U-235 Enrichment is 19.75 %; Uranium density in fuel (2.96 g/cm3) With a new fuel management pattern, the five melting fuel elements are the F-26, F-31, F-32, F-36, and F-37 with burn-up respectively 37.94 %, 32.55 %, 44.82 %, 40.90 % and 20.81 % as seen in Fig 4 (Setiawan et al.,

2020; Kuntjoro et al., 2019)

Radionuclide activity that can reach the reactor stack is obtained from the following equation:

QS=Q1+Q2= (0.4 × f1×f2×f3×A) + (0.6 × f1×f2×f3× (1 − η A) ×A)

(1) Where A is an inventory activity (Bq); Q1 is radionuclide activity in cooling water (Bq); Q2 is radionuclide activity released into the reactor hall (Bq); f1 is radionuclide fraction that can escape from the fuel going

to the cooler; f2 is radionuclide fraction that can release from the coolant

to the reactor chamber; f3 =iodine fraction; and η =efficiency of reactor stack filters The values of f1 and f2 for noble gases are 1.0 and the Br nuclides are 5 × 10− 4 The value of f1 is 0.5 for iodine (element or organic) or other nuclides The f2 values for the Iodine element are 5 ×

10− 4 and 5 × 10− 2 for organic Iodine The value of f 2 for other nuclides

is 1 × 10− 5 The release fraction f3 for iodine (element or organic) is 0.5 The efficiency of the stack filter for noble gases is 0.0 The efficiency of the stack filter for Br and Iodine elements is 0.99 and for organic iodine

or other nuclides is 0.90 (BATAN, 2019; Kuntjoro and Udiyani, 2005)

2.2 Radioactivity and radiological concequences

Estimates for radioactivity of atmospheric dispersion and surface deposition use the segmented Gaussian equation default from PC- Cosyma (European Commission, 1995) It uses a segmented Gaussian plume model which allows for hourly changes in the wind speed and direction, stability category and rainfall rate affecting the dispersing material The segmented plume model Musemet incorporated in PC-Cosyma was employed for the calculations; it is an improved linear Gaussian plume model, which assumes that the meteorological condi-tions (wind direction, wind speed, stability category and rain intensity) are known and constant in subsequent time intervals of 1 h (European Commission, 1995; Panitz et al., 1989)

The segmented Gaussian plume model allowing of atmospheric conditions and wind direction will changes during plume travel This model derives the sequences of atmospheric conditions affecting the plume from a data file giving hourly averages for wind speed and di-rection, stability category, precipitation intensity and mixing layer depth The linear Gaussian for atmospheric dispersion shown in following equation

P.M Udiyani et al

χ(x, y, z) = Q

2πσ y σ z μ

[

− 1

/

2(y/σ y

)2]{

exp

[

− 1

/

2((z − H)/ σ z)2

] +exp

[

− 1

/

2((z + H)/ σ z)2

]}

(2)

Where X (x,y,z) = Concentration in the air (chi) on the x-axis, y, z (Bq.s/

m3): Q = Source term (Bq): μ =Wind speed (m/s): σ =Horizontal

dispersion coefficient (m): σ =Vertical dispersion coefficient(m): H =

Effective height (m): y = Distance perpendicular to the wind (m): z =

Height above ground (m)

Generally, with respect to Gaussian dispersion modelling,

atmo-spheric turbulence is classified by empirical turbulence-typing schemes

The most widely used scheme is the one developed by Pasquill and

Gifford (European Commission, 1995; Panitz et al., 1989), which assigns

the grade of atmospheric stratification to six diffusion categories Class A

corresponds to very unstable conditions and is associated with small

mechanical but large thermal components of turbulence Class B is

moderately unstable and Class C is slightly unstable Class D represents

the neutral atmospheric conditions and turbulence is only due to the

mechanical component Class E is moderately stable, and Class F

cor-responds to thermally very stable conditions and the mechanical

tur-bulence tends to be damped by buoyant forces (Panitz et al., 1989)

Meteorological data such as weather stability, wind direction, wind

speed and solar radiation are taken from the latest data (2016) from the

KNS Data were taken every hour for one year for 16 wind direction sectors Wind rose of KNS area is depicted in Fig 2

As seen in Fig 2, the dominant wind direction blows towards the south (occurrence frequency is about 28 %) with a dominant speed between 2.4 and 3.8 m/s (occurrence frequency is around 8 %) Sta-bilities: 29.0 % stability D; 26.0 % stability E; 18 % stability F, and 27 % stability C rain

Calculation of radiation doses through four main pathways are external gamma and beta from cloud shine, external gamma from sur-face ground, inhalation of cloud shine, and ingestion of contaminated food, as illustrated in Fig 3 Local production data or agriculture and livestock such as grain products, leafy vegetable, non-leafy vegetable, root vegetable, milk, meat cow and sheep meat are taken for 16 wind directions for 9 radius distances (500 m; 1.0 km; 1.5 km; 2.0 km; 2.5 km; 3.0 km; 3.5 km; 4.0 km; and 4.5 km)

2.3 Countermeasure

Anticipatory actions are carried out according to certain criteria and the time and duration of the action based on the dose exposed in the location area A dose-based evacuation measure is taken if the

com-munity receives a total effective body dose >0.05 Sv, that is, the dose

can cause non stochastic effects While sheltering is for receiving doses

between 0.02 and <0.05 Sv, and the dose received for Iodine tablets is

0.02 Sv (Publication 10, 2007; BAPETEN, 2013) Restrictions on the

Fig 1 Methodology approach of radiological consequences calculation

Progress in Nuclear Energy 140 (2021) 103927

consumption of local food (food bans) are determined based on the dose

received from contaminated agricultural and livestock products

3 Results and discussions

3.1 Reactor core inventory and source term of BDBA

The RSG-GAS equilibrium core consists of 40 Fuel Elements (FEs)

and 8 Control Elements (CEs), arranged in 6 burn-up classes with each

BU class representing the burn-up fraction of 8 % (Kuntjoro et al., 2019)

Old fuel management patterns that melt is FE-26 (Fuel element-26),

FE-31, FE-32, FE-36 and FE-37 with burn-up successive 16 %, 48 %,

8 %, 40 % and 40 % While for the new fuel management pattern is the F-26, F-31, F-32, F-36 and F-37 with burn-up respectively: 37.94 %, 32.55 %, 44.82 %, 40.90 % and 20.81 %

The condition of the five melted fuels is simulated for the calculation

of the worst accident condition source term Each fuel element and control element consist of 21 and 15 U3Si2–Al fuel plates with a 19.75 % uranium enrichment In the old fuel management pattern, the reactor core consists of 7 burn-up classes with an 8 % burn-up class and 6/1 fuel/control replacement pattern for 6 cycles and 6/2 fuel/control in the 7th cycle and over every 7 cycles As for the new fuel management pattern, the reactor core consists of 8 burn-up classes with a 6.20 % burn-up class The reactor core replacement pattern is 5/1 fuel/control element per cycle

From Fig 4, it can see that in each box, the first line shows the type of fuel of FE or CE, the second line depicts the burn-up fraction in BOC (%) and the third line states the Power Peaking Factor (PPF) in FE or CE RSG-GAS reactor has 4 Central Irradiation Position (CIPs) of and also 4 Irradiation Position (IPs) CIP and IP are intended for material irradia-tion for research purpose as well as for the radioisotope producirradia-tion After the fuel melted is determined, an inventory calculation is done for each management pattern for each of the five fuels using the ORIGEN-2.1 For the nuclear library, the Thermal Library embedded in ORIGEN-2 is used The inventory calculation was carried out for FE with

1 fresh FE consisting of 0.25 kg of U3Si2–Al with an enrichment of 19.75

% Burn-up calculation is carried out with a combustion power of {30 MW/[40 + ((15/21) × 8)]} × {PPF of each FE} for 25 days (1 cycle of operation)

Inventory calculations use melt pattern based on new management, since it provides more pessimistic inventory activities Source term calculations using mechanism approach do not involve filtering in filter stack Assumptions without a stack filter will be obtained from pessi-mistic source terms

Calculation results for inventory of 5 melted fuel and BDBA accident postulation source term, shown in Table 1 Inventory of reactor fuels is classified into 8 groups, namely: the noble gas group (Cr, Xe); Halogen Group (I, Br); Alkali group metal (Cs); the Tellurium group (Te and Sb); Strontium and Barium (Sr, Ba); Noble metal (Ru and Rh); Lanthanide

Fig 2 Wind rose in the KNS area of RSG-GAS site

Fig 3 Four main pathways are external gamma and beta from cloud shine,

external gamma from surface ground, inhalation of cloud shine, and ingestion

of contaminated food

P.M Udiyani et al

Fig 4 Equilibrium core for new fuel management patterns

Table 1

Fuel inventory and source terms for BDBA postulation of RSG-GAS

Radionuclide group Nuclide Fuel Inventory (Bq) Source term (Bq) Radionuclide group Nuclide Fuel Inventory (Bq) Source term (Bq) Noble Gas Kr-85 8.38E+12 8.38E+12 Strontium and Barium Sr-89 3.34E+15 1.67E+10

Kr-85m 6.31E+14 6.31E+14 Sr-90 6.66E+13 3.33E+08 Kr-87 8.64E+14 8.64E+14 Ba-139 3.74E+15 1.87E+10 Kr-88 1.63E+15 1.63E+15 Noble Metal Ba-140 3.62E+15 1.81E+10 Xe-133 3.89E+15 3.89E+15 Ru-105 6.44E+14 3.22E+09 Xe-135 6.27E+14 6.27E+14 Ru-106 1.16E+14 5.82E+08 Halogen I-131 1.65E+15 4.11E+11 Rh-103m 2.01E+15 1.00E+10

I-132 2.48E+15 6.20E+11 Rh-105 5.36E+14 2.68E+09 I-133 3.92E+15 9.79E+11 Lanthanides La-140 3.68E+15 1.84E+10 I-134 4.40E+15 1.10E+12 Y-90 7.15E+13 3.57E+08 I-135 3.66E+15 9.15E+11 Y-91 4.04E+15 2.02E+10 Alkali Metal CS-134 1.82E+13 9.08E+07 Nb-95 4.30E+15 2.15E+10

CS-137 6.91E+13 3.45E+08 Pr-143 3.39E+15 1.69E+10 Rb-88 2.09E+15 1.05E+10 Nd-147 1.31E+15 6.56E+09 Tellurium Te-132 2.47E+15 1.23E+10 Cerium Ce-141 4.01E+15 2.01E+10

Sb-125 8.00E+13 4.00E+08 Ce-143 3.42E+15 1.71E+10 Sb-127 8.00E+13 4.00E+08 Ce-144 1.81E+15 9.06E+09

Table 2

Mean concentration of nuclides on air or on ground surface

Distance (km) Noble gas Halogen Alkali metal Other Nuclide

Air Bq.s/m 3 ground Bq/m 2 air Bq.s/m 3 ground Bq/m 2 air Bq.s/m 3 ground Bq/m 2 air Bq.s/m 3 ground Bq/m 2

0.500 1.93E+10 0.00E+00 7.01E+08 6.93E+06 1.07E+05 1.07E+02 3.37E+06 3.37E+03 1.000 6.37E+09 0.00E+00 2.01E+08 1.99E+06 3.40E+04 3.40E+01 1.08E+06 1.08E+03 1.500 3.35E+09 0.00E+00 9.58E+07 9.45E+05 1.75E+04 1.75E+01 5.56E+05 5.56E+02 2.000 2.01E+09 0.00E+00 5.82E+07 5.73E+05 1.10E+04 1.10E+01 3.46E+05 3.46E+02 2.500 1.44E+09 0.00E+00 4.07E+07 4.01E+05 8.09E+03 8.09E+00 2.53E+05 2.53E+02 3.000 1.24E+09 0.00E+00 3.35E+07 3.30E+05 7.08E+03 7.08E+00 2.27E+05 2.19E+02 3.500 1.07E+09 0.00E+00 2.78E+07 2.73E+05 6.31E+03 6.31E+00 1.94E+05 1.94E+02 4.000 9.35E+08 0.00E+00 2.40E+07 2.36E+05 5.62E+03 5.62E+00 1.72E+05 1.72E+02 4.500 7.67E+08 0.00E+00 1.94E+07 1.91E+05 4.64E+03 4.64E+00 1.41E+05 1.41E+02

Progress in Nuclear Energy 140 (2021) 103927

Group (La, Y, Nb, Pr, N and Sm), and Cerium Group (Ce) (Yangmo et al.,

2014; Herranza et al., 2015)

3.2 Radioactivity on air dispersion or surface deposition

The results of the calculation of radioactivity disperse in the air and

disposition on the surface are listed in Table 2 Nuclear radioactivity is

grouped in 4 types, namely: Nuclides from noble gas (Xe, Kr); Alkali

metal (Cs, Rb); Halogen (I); and Other Nuclide (Sr, Y, Te, Nb, Pr, Ce, Nd,

Ba, La, Ru, Sb and Zr)

Table 2 shows the averaged radioactivity in atmospheric air for each

radius The highest activity that is dispersed in sector 9 is the sector that

has a radial angle deviation ±202.50 from the North From the data it

can also be seen that for the same nuclide, radioactivity decreases with

increasing radius of the RSG-GAS The highest radioactivity is at a radius

of 500 m, while the lowest is at a radius of 4.5 km from the release

center

Radioactivity in the air affects the contribution of radiation doses

that human receive from inhalation exposure pathways and direct

exposure from the air (cloudshine) The highest radioactivity in the air

and at ground level (except for noble gases) occurs in a 500 m radius

area from the center of release The highest total radionuclides in the

noble gas group (Xe and Kr) are 1.93E+10 Bq.s/m3; from group Halogen

is 7.01E+08 Bq.s/m3; and 1.07E+05 Bq.s/m3 from the Alkali metal

group; as well as from other nuclides groups of 3.37E+06 Bq.s/m3

Although the highest radioactivity in the air is in the noble gas group,

but generally noble gas have a short half-life The shortest half-life of

noble gas is Kr-87 (1.3 h), Kr-88 (2.8 h), Cr-85m (4.5 h), Xe-133 (5.27

days), and the longest is Xe-135 (9.1 days) Since the half-life is short

and cannot react with matter (inert), then the accumulation effect is

small This results in the contribution to the radiation dose not being too

large when compared with radionuclides which have a long half-life or

from radionuclides which are not a noble gas group For the dispersion

in the air the highest radionuclide activity comes from the noble gases

Since it is inert, then the noble gas will not be deposited at the soil

surface

From Table 2, it can be seen that the highest radioactivity of

depo-sition is from the Halogen group or the Iodine group, which is equal to

6.93E+06 Bq/m2 Nuclei I-131 will gradually be disposed to ground and

plants which will then enter the food chain towards livestock and

humans These nuclides in addition to donating internal doses through

food and inhalation, also contributors to external doses through the

ground surface and radioactive clouds Its effect on internal dosages in

plant consumption from fruit is not too large because the half-life is

relatively short (8.04 days) compared to the time of plant growth A

significant contribution to the radiation dose from radionuclide

depo-sition comes from Cs-137 radionuclide The long half-life is 30.17 years,

making additional doses of the effects of accumulation from the food

chain

3.3 Dose consequences

The results of the calculation of short-term doses of the external

exposure and inhalation received by the community around the RSG-

GAS (within a 5 km radius) are in Table 3 Based on the distance of

acceptance, the dose is reduced by increasing the radius from the

reactor The maximum short-term individual effective dose is 1.31E-03

Sv, and 2.44E-03 Sv for long-term dose respectively This dose value is

below the maximum limit for the exclusion area of 0.25Sv (Publication

10, 2007), and the limit of 0.005 Sv for certain conditions for the public

(BAPETEN, 2013)

The amount of dose received is proportional to the activity of

radioactive dispersion and deposition Meteorological conditions will

determine the dispersion model that occurs, it will then affect the drop

site and surface deposition

The largest collective dose is found in an area at a radius of 2 km from

the center of detachment, that is 4.57E+00 man-Sv The effective indi-vidual dosage received is still below to the recommended dose limit of the Bapeten regulatory body for the general public (BAPETEN, 2013)

3.4 Countermeasure

Countermeasures are carried out, based on estimated radiation doses received by the public at the Serpong Nuclear Area (KNS) site Based on the dosage data in Table 3, no countermeasure action were taken Dose data in Table 3 showed that the short-term dose not meet the criteria for Iodine tablet blocking to 0.02 Sv dose; sheltering for receiving doses exceed 0.01Sv; and for evacuation if the dose exceeds reception 0.05 Sv From the results of research for BDBA condition, the emergency zoning

of the Serpong nuclear area (KNS) is not significantly different from the emergency zoning made based on the DBA accident Communities around KNS in the same zoning of DBA and BDBA received radiation doses for countermeasure criteria that were not different i.e there is no need for particular action of giving iodine tablets, sheltering, or evacuation

4 Conclusions

In this study, the consequences of RSG-GAS doses with a power of 30 MWt after 30 years of operation are evaluated based on BDBA postula-tion The study was conducted using the latest input data of BDBA source term and meteorology data, population data, environmental data in

2016 The calculation resulted in the maximum effective dose received

in sector 9 (southward) within a radius of 0.5 km from the reactor The maximum short-term effective individual dose received is 1.31E-03 Sv, under the Bapeten regulatory body’s accident limits for the exclusion area of 0.25 Sv, and the limit of 0.005 Sv for certain conditions for the community The study results also state that countermeasure measures such as Iodine tablet blocking, sheltering, and evacuation, are not needed

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper

Table 3

Dose Consequences of RSG-GAS BDBA accidents

Distance (km) Mean Individual dose effective (Sv) Mean Individual dose of thyroid (Sv) Collective dose (man.Sv)

Short- term Long- term Short- term Long- term 0.500 1.31E-

03 2.44E- 03 1.47E- 03 2.68E- 04 2.01E+00 1.000 5.12E-

04 1.17E- 03 5.74E- 04 1.02E- 04 2.30E+00 1.500 2.85E-

04 6.82E- 04 3.20E- 04 5.59E- 05 3.72E-06 2.000 1.86E-

04 4.68E- 04 2.00E- 04 3.62E- 05 4.57E+00 2.500 1.46E-

04 3.59E- 04 1.64E- 04 2.83E- 05 2.89E-06 3.000 1.34E-

04 3.17E- 04 1.50E- 04 2.57E- 05 1.67E+00 3.500 1.03E-

04 2.32E- 04 1.16E- 04 1.99E- 05 6.98E-07 4.000 9.38E-

05 2.00E- 04 1.05E- 04 1.81E- 05 7.43E-01 4.500 8.12E-

05 1.78E- 04 9.13E- 05 1.56E- 05 1.32E-07

P.M Udiyani et al

Acknowledgement

This work is conducted with 2019 research funding of the Center for

Nuclear Reactor Technology and Safety (PTKRN), BATAN It is also

partially supported by 2018–2019 National Research Incentive RISTEK-

DIKTI and 2020 LPDP Ministry of Finance Incentive Program Thanks to

all colleagues in the Center for Multipurpose RSG-GAS who have

pro-vided technical assistance related to this research

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