Establishment and Application of Control Room Habitability Methodology forMaanshan Nuclear Power Plant
Kai-Chun Yang 1,Jong-Rong Wang 1,2, Hsiung-Chih Chen 1,2, Shao-Wen Chen 1,2, Chunkuan Shih 1,2,Wen-Sheng Hsu 3
1: Institute of Nuclear Engineering and Science, National Tsing Hua University
2: Nuclear and New Energy Education and Research Foundation
3: Nuclear Science and Technology Development Center, National Tsing Hua University
Address: No. 101, Section 2, Kuang-Fu Road, Hsinchu, Taiwan 30013, R.O.C.

Key words: RADTRAD, HABIT, Habitability

Abstract
In this study, we focus on the establishment and application of the control room habitability methodology forMaanshan PWR Nuclear Power Plant (NPP) by using RADTRAD and HABIT codes. Therefore, there are twosteps in this study. The first step is to use RADTRAD and HABIT codes to establish the analysis methodology.
We use the Final Safety Analysis Report (FSAR) and other data for Maanshan NPP as the input data in theRADTRAD and HABIT models. Second, we use these models to evaluate the control room habitability for theLOCA and CO2 storage burst cases. The analysis results of RADTRAD for the LOCA case are similar to FSAR
data. The HABIT results for the CO2 storage burst case are below the R.G. 1.78 failure criteria. The above
results indicate that Maanshan NPP habitability can be maintained.

1. Introduction
Maanshan nuclear power plant is located in thesouth of Taiwan. The type of reactor is Pressurized
Water Reactor (PWR). The nuclear steam supply
system of the nuclear plant includes the reactor,auxiliary equipment and the reactor coolant system(RCS), etc. The RCS contains three loops. Each loop
contains a reactor coolant pump (RCP) and a steam
generator. The hot side of the secondary loop is
equipped with a pressurizer to adjust the pressure ofthe RCS circuit.
The safety analysis of nuclear power plants is avery important assessment, especially after theFukushima accident in Japan. The safety
requirements of nuclear power plants are increasingin Taiwan. National Tsing Hua University in 2016
joined the RAMP (Radiological Protection Computer
Code Analysis and Maintenance Program) led by US
NRC. The RAMP program's main research area is tofocus on radiation dose assessment, control room
habitability, nuclear power plant decommissioning
and so on. RADTRAD and HABIT are both codes
included in RAMP. RADTRAD can perform the dose
calculations for the radioactive materials migration

and removal. HABIT can calculate toxic chemicals
concentration for the habitability of the control room.
Therefore, this study uses the RADTRAD andHABIT codes to establish the analysis methodology
for the evaluation of the Maanshan control room
habitability. This control room habitability evaluation
has two parts: the radiation dose assessment for theDBA LOCA case and the chemical concentrationassessment for the CO2 storage burst case.
2. Analysis of case and model description
2.1 Analysis program
2.1.1 SNAPThe Symbolic Nuclear Analysis Package (SNAP)
consists of a suite of integrated applications designed
to simplify the process of performing engineering
analysis. SNAP is built on the Common Application
Framework for Engineering Analysis (CAFEAN)
which provides a highly flexible framework forcreating and editing input for engineering analysis
codes as well as extensive functionality forsubmitting, monitoring, and interacting with thecodes. SNAP is developed by Applied Programming
Technology (APT), Inc. and is sponsored by the NRC.
It provides the RADTRAD user with a graphical user

6th East Asia Forum on Radwaste Management Conference
November 27-29, 2017, Osaka, Japaninterface with pre– and post–processor capabilities
allowing users to develop RADTRAD input decks.
2.1.2 RADTRAD
RADTRAD(RADionuclide,Transport,Removal and Dose Estimation Computer Code) is
one of the RAMP codes. RADTRAD can be used
for the calculation of transport and removal ofradionuclides and dose at Exclusion Area Boundary(EAB), Low Population Zone (LPZ), and the controlroom.
2.1.3 HABIT
HABIT V2.0 is a package of computer codes
designed to assist in the evaluation of Light-Water
Reactor (LWR) control room habitability in the eventof accidental spills of toxic chemicals. It consists of anumber of program modules and produces files
containing tabular output that can be printed, viewed,
or imported into spreadsheet programs for further
applications. HABIT V2.0 also implements aheavy-gas dispersion model, unifies input screen ofEXTRAN, DEGADIS and SLAB, and incorporates
Bitter Mc-Quaid calculation to determine whichmodel needs to run and provide plotting theconcentration versus time outputs.

by the atmospheric environment and spread to thecontrol room. The air intake of the control room may
inhale air with carbon dioxide, so if too much
inhalation of carbon dioxide, it may cause damage tothe staff in the control room. Therefore, we use
HABIT to analyze the case according to RG 1.78.
2.3 Models establishment
2.3.1 RADTRAD/SNAP model
Maanshan Nuclear Power Plant model is shown inFigure 1. The reference is from the FSAR Chapter 15of Maanshan Nuclear Power Plant[3]. Block 1 is thesimulated atmospheric environment region, block 2 isthe unsprayed region of the containment, and block 3
is the spray region of the containment. The junctions
between the blocks are simulated for their exchangeor leakage. The region of the containment was
divided into sprayed region (81%) and unsprayedregion (19%). The exchange rate is 33000cfm
between the two regions. Assuming that the leakage
rate of the containment is 0.1 vol% / day (0 to 1 day);0.05 vol% / day (1 to 30 days) for a total of 720 hours.
In addition, TID-14844 is selected as the radiation
source in this model, the other important input data [3]as shown in Table 1 to Table 4.

2.2 Description of cases
2.2.1 LOCA caseIn the FSAR of Maanshan nuclear power plant, theLOCA case is assumed that a RCS pipe ruptures.
Additionally, the radionuclides are assumed torelease from the containment. The related
assumptions are as follows:1.
The reactor core equilibrium noble gas andiodine inventories are based on long-term
operation at 2900 MW.
2.
When the accident occurs, 100% noble gas isreleased into the containment and isimmediately leaking from the containment tothe atmospheric environment.
3.
When the accident occurs, 25% radioactive
iodine inventory is released into thecontainment, and immediately leak from thecontainment to the atmospheric environment.
4.
For the iodine fission product inventory
released to the containment, 91% iselemental iodine, 5% is particulate iodine,and 4% is organic iodine.
5.
Credit for iodine removal by the containment
spray system is simulated in this case.
6.
The control room filter efficiency is 99% foriodine.

Figure 1: RADTRAD / SNAP model of Maanshan
nuclear power plant
Table 1: χ / Q value

2.2.2 CO2 storage burst case
Assuming that the CO2 storage tank in Maanshan
nuclear power plant is exploded, the CO2 is released
to the atmosphere by a large amount and is affected

6th East Asia Forum on Radwaste Management Conference
November 27-29, 2017, Osaka, Japan

Table 2: DCF values

Table 3: nuclear stock inventory

Table 4: Respiratory rate

2.3.2 HABIT model
The methodology established in this study isshown in Figure 2. First, we collect and investigate
the relevant information of Maanshan nuclear power
plant, such as: chemical species in and out of power
plant, location, inventory, weather and otherinformation, and the reference data used in this study
is from Maanshan nuclear power plant information,
manual and FSAR report [3] - [6]. These chemicals
are then screened according to rule of R.G. 1.78[6].
R.G. 1.78 sets the rules mainly based on the locationof chemicals, distance, inventory, etc. The chemicals
screened out means that does not cause harm to thecontrol room. The chemicals that are not screened out
may cause harm to the control room and need further
analysis by HABIT.
R.G. 1.78 can be divided into two types ofstationary sources and mobile sources, stationary
sources are usually chemical storage tanks or a small
amount of chemicals in bottle or barrow inlaboratories, mobile sources are usually trucks, Train,boat, etc. loaded with chemicals, as follows:
screening criteria for stationary sources:
Chemicals stored or situated at distances
greater than 8 km from the plant need not be
consideredIf sources of hazardous chemicals such within a8-km radius of the plant, and in quantities lessthan a given toxicity limit and stablemeteorological conditions, these sources neednot be considered in the evaluation of control
room habitability.
Any hazardous chemical stored onsite within
500 m of the control room in a quantity greaterthan 45 kg should be considered for control
room habitability evaluation.
Small quantities for laboratory use, 9.07 kg orless, are exempt.
screening criteria for mobile sources
If hazardous chemicals outside a 8-km radius of
a nuclear power plant, the shipments need not
be considered for further evaluation.
If the shipments are within a 8-km radius of a
nuclear power plant, estimates of thefrequencies of these shipments should beconsidered in the evaluation of control room
habitability. Shipments are defined as being
frequent if there are 10 total shipments per year
for truck traffic, 30 per year for rail traffic, or
50 per year for barge traffic.
Frequent shipments need not be considered in
the analysis if the quantity of hazardous
chemicals is less than the quantity shown in
R.G. 1.78
The inventory of carbon dioxide in this case is
45,000 kg and its distance is less than 0.5 km.

6th East Asia Forum on Radwaste Management ConferenceNovember 27-29, 2017, Osaka, Japan

According to R.G. 1.78, it could not be screened out,
so it need further analysis in HABIT, Table 5 lists theparameter value of this case in HABIT.
HABIT 2.0 is used in this study, HABIT operation
screen is shown in Figure 3. HABIT is divided into
two sub-modules which are EXTRAN and CHEM.
HABIT first performs EXTRAN. After EXTRAN
calculation is completed, HABIT then performs
CHEM calculation. EXTRAN calculates theconcentration of chemicals at the air intake of thecontrol room which diffuse through the atmosphericenvironment when the gaseous or liquid chemical
explodes or leaks, as shown in Figure 4. EXTRAN
use mass balance equation, energy balance equationand puff diffusion model to calculate which is basedon the property and inventory of chemicals,
combined with the conditions of the atmosphericenvironment. According to the results calculated by
EXTRAN, CHEM uses this result, combined with therelevant information of the control room (such as theflow rate of the inlet and the volume of the controlroom). The mass balance equation is used to calculate
the concentration of the air into the control room. Asshown in Figure 5. As HABIT calculation iscompleted, it will automatically display the file andthe data output as text files, as shown in Figure 6.

Figure 3: settings of HABIT

Figure 4: settings of EXTRAN

Figure 2: flow chart of Methodology

Figure 5: settings of CHEM

6th East Asia Forum on Radwaste Management Conference
November 27-29, 2017, Osaka, Japan

Figure 6: HABIT analysis results

The RADTRAD/SNAP model has a certain degreeof credibility according to the comparison results. Inaddition, Table 6 and Table 7 shows that although theresults of RADTRAD analysis and FSAR data aresimilar, there are some numerical differences. The
difference may come from two aspects:
1.
Differences are between FSAR analysis
model or code and RADTRAD. However,
FSAR did not describe its analysis model orcode in detail. Therefore, we cannot confirm
it.
2.
Some parameter values are not included in
FSAR. For example, FSAR does not specify
the stop time of the containment spraysystem, and this parameter may affect theanalysis results.

Table 5: Input parameters in HABIT

3. Analysis results and discussion
3.1 RADTRAD / SNAP analysis results
According to FSAR 15.0 [3], the results of thecalculated dose shall comply with the criteria in 10
CFR 100.11:
For the EAB:
A total radiation dose to the whole body is
below 250 mSv.
A total radiation dose to the thyroid fromiodine exposure is below 3000 mSv within 2hours after the accident.
For the LPZ:
A total radiation dose to the whole body is
below 250 mSv.
A total radiation dose to the thyroid fromiodine exposure is below 3000 mSv during theentire period of radioactive cloud passage.
Figure 7 shows the output of RADTRAD. The
results of the calculation at EAB and at LPZ areshown in the figure. Table 6 and Table 7 show thecomparisonoftheanalysis
resultsofRADTRAD/SNAP model of Maanshan nuclear
power plant at EAB and LPZ with the FSAR and theregulatory limits. From the table, we can see that theanalysis dose at EAB and LPZ are similar with thedata in the FSAR, and are lower than the regulatory
limits.

Figure 7: RADTRAD result data

Table 6: analysis dose at EAB of Maanshan nuclearpower plant
EAB

FSAR

RADTRAD

Regulatory
limitsWhole bodydose(mSv)

9.9

9.273

250

Thyroiddose(mSv)

469

379.24

3000

Table 7: analysis dose at LPZ of Maanshan nuclear
power plant
LPZ

FSAR

RADTRAD

Regulatory
limitsWhole bodydose (mSv)

5.94

6.0914250

Thyroiddose (mSv)

629

785.953000

6th East Asia Forum on Radwaste Management Conference
November 27-29, 2017, Osaka, Japan

3.2 HABIT analysis results
The analysis results of the HABIT are shown inTable 8. The maximum concentration appears at 1.25
minutes after the explosion, which is 3.166 g / m3.
According to RG 1.78 [6], the limit concentration ofcarbon dioxide is 7.36 g / m3. The result of HABIT isless than this limit, which means the concentration ofcarbon dioxide in this case does not harm thepersonnel in the control room.
Table 8: HABIT analysis results for CO2 storage tank
explosion case of Maanshan nuclear power plant

HABIT
R.G. 1.78
limitsTime (min)Concentration (g/m3)

1.25

3.166
7.36

4. Conclusion
This study used the RADTRAD, SNAP, andHABIT codes to establish the methodology forcontrol room habitability. The RADTRAD/SNAPmodel was successfully established by referring to
the FSAR and data of Maanshan nuclear power plant
and the RADTRAD manual. And this model wasused to analyze the“release from the containment”
case of LOCA. The RADTRAD analysis result showsthat the dose at EAB and LPZ are similar to theFSAR data and both are lower than the regulatorylimits. The above comparison shows that we haveestablished the RADTRAD / SNAP model ofMaanshan nuclear power plant with a certain degreeof credibility. This model will apply to the researches
related to radiation dose of Maanshan nuclear power
plant in the future, such as LOCA ESF leakage.
Based on the above experience and methods, we willproceed to perform the establishment and applicationof RADTRAD/SNAP models for the other nuclear
power plants in Taiwan.
On the other hand, the HABIT model wassuccessfully established by referring to the FSAR anddata of Maanshan nuclear power plant and theHABIT manual. This model was used to analyze the“CO2 storage tank explosion” case. The HABIT
analysis result shows that the chemical concentration
is lower than the limits of R.G. 1.78, which means thehabitability of control room would be maintained.
This model will apply to the researches related to thehabitability of control room of Maanshan nuclear
power plant in the future. In addition, based on theabove experience and methods, we will proceed toperform the establishment and application of analysis
methodology of HABIT models for the other nuclear
power plants in Taiwan.

5. References
1.
U.S. NRC, RADTRAD: A Simplified Modelfor RADionuclide Transport and Removal And
Dose Estimation, NUREG/CR-6604, 1997.
2.
SNAP/RADTRAD: Description of Models andMethods, W. C. Arcieri, D.L. Mlynarczyk, L.
Larsen, July 2015.
3.
Maanshan Nuclear Power Station Final Safety
Analysis Report (FSAR), 2013.
4.
U.S. NRC, Computer Codes for Evaluation ofControl
Room
Habitability(HABIT),
NUREGICR-6210, 1996.
5.
Taiwan Power Company, Maanshan Nuclear
Power Station Training materials, 2006.
6.
U.S. NRC, REGULATORY GUIDE 1.78,
EVALUATING THE HABITABILITY OF A
NUCLEAR POWER PLANT CONTROLROOM
DURINGAPOSTULATEDHAZARDOUS CHEMICAL RELEASE, 2001.
7.
U.S. NRC, REGULATORY GUIDE 1.23,
METEOROLOGICALMONITORINGPROGRAMS FOR NUCLEAR POWER
PLANTS, 2007.

6th East Asia Forum on Radwaste Management Conference
November 27-29, 2017, Osaka, Japan