Proposed tool for selecting protective
actions in a nuclear emergency:
balancing radiological and nonradiological (psychosocial) impacts
January 18, 2023

Tristan Barr
Section Head
Planning, Outreach, Exercises and Training
Radiation Protection Bureau
Health Canada – Santé Canada
Tristan.w.Barr@hc-sc.gc.ca

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{Classification}

Premise• Current nuclear emergency response plans are wellestablished and provide clear guidance on radiation dosethresholds for implementing protective actions to minimize
radiation doses• Protective actions that minimize radiation doses may
increase the psychosocial impacts to the population (e.g.
evacuation and relocation)• Can we develop a unit and tool to compare psychosocial
detriment to radiation detriment?
• This tool could help justify and optimize evacuation andrelocation decisions in a protection strategy2{Classification}

Project Overview - Approach
The project was executed in two phases
Secondary Research: A literature search was conducted to:1.

Identify common psychosocial impacts resulting from nuclear emergencies;2.

Understand the specific drivers of these impacts; and3.

Identify measurement tools used to understand psychosocial impact in a nuclear
context.

Decision-Support Tool Development: The decision-support
tool was developed using the following steps:
1.

Identifying available Canadian data for developing a tool

2.

Leveraging the literature to develop a structure for the tool and using quantitative
estimates from the literature to quantify potential impacts

3.

Building, testing, and reviewing the tool over several iterations

3{Classification}
Summary of secondary research review anddevelopment of a unit for a non-radiological Sievert• Literature review identified the main drivers forpsychosocial impacts:Residence-related factors
Risk perception
Socioeconomic changes• Can we propose a weighting
factor for each of these main
drivers that contribute to an overall
psychosocial detriment?

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How to convert psychosocial impacts for comparison to sieverts?
•Weighting factor approach is similar to radiation
weighting factors and tissue weighting factors
used to generate the sievert – a unit of overall
detriment.

•Propose weighting factors for drivers of
psychosocial detriment and the outcomes that
produce measurable psychosocial impacts•••

Residence changes
Risk Perception
Socioeconomic changes•••••

Depression
PTSD
Anxiety
SuicideSubstance abuse
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{Classification}

Data is not available to generate a non-Radiological sievert• Mental health and psychosocial impacts from nuclear
emergencies have been measured with general andsummary indicators• NRC 2021 paper quantifies various non-radiological healtheffects from evacuations/relocations but specifies that they
are not additive• Cannot weight the psychosocial impacts and sum them up
to get a sievert-like unit at this time• Need specific studies on the non-radiological healtheffects that measure each health effect and their
combined impact6

{Classification}

Summary of research results: No significant difference•••

A model was used to evaluate the changes in outcomes (psychosocialimpacts) between a Canadian population that is affected by thedisaster and one that is not.
Data from the Canadian Community Health Survey (CCHS) was used
to evaluate psychosocial impacts that arise from an evacuation fromthe 2013 Alberta Flood data.
The variables:Life Satisfaction: is used to capture changes in subjective well being froman evacuation. It refers to how satisfied a person feels with their life ingeneral
Time period: Pre-flood and post-flood
Postal Code: Captures an individual’s proximity to the flood as a proxy for
individuals affected by the flood / evacuation
Control variables: used to control for additional factors that affect life
satisfaction. These include socioeconomic controls (e.g. income,education), demographic controls (e.g. gender, age, martial status), andphysical/mental disorders (e.g. chronic healthconditions, mood/anxiety disorder).
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Proof of concept
Evacuation

Non-Evacuation
1. Psychosocial Costs for NonEvacuation
Anxiety, depression, posttraumatic stress disorder(PTSD), or other psychosocial
impacts for a number ofreasons (e.g., fear of radiation,
potential loss of family
members, stress from negative
media reporting).

2. Radiological Cost of NonEvacuation
Radiological harm: Guidancevalues on projected dose aremonetized using the U.S.
Nuclear Regulatory
Commission’s (U.S.NRC)
conversion factor

NonEvacuation
Impacts

PsychosocialandRadiological
Impacts
AssociatedwithNonEvacuation

1.

Psychosocial Cost ofEvacuation
Psychosocial risks including
depression, anxiety, and PTSD,
as individuals are removed fromtheir communities and their lives
are uprooted. The psychosocial
impact is captured using an
estimate of the prevalence ofdepression then monetized.

2.

Radiological Cost of
Evacuation (OPTIONAL)
It is possible that populations
experience some radiologicalharm prior to being evacuated.
The decision-support framework
captures this cost by monetizing
radiological harm using the same
methodology applied to the nonevacuation scenarioEvacuation
Impacts
PsychosocialandRadiologicalImpacts
Associatedwith
Evacuation

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Estimating the Psychosocial Impacts of Non-Evacuation

Component

The psychosocial impact of an RN emergency for non-evacuated populations is captured using an
estimate of the impact of an RN emergency on life satisfaction.
The empirical estimates of the life satisfaction impact of an RN emergency are taken from the postFukushima Daiichi nuclear power plant accident literature.
Estimates of Life Satisfaction
Impacts from a RN Emergency

Monetization

Life Satisfaction Impact(Life Satisfaction Points)

Life Satisfaction
Monetization($)• The estimated coefficient forlife satisfaction impact withrespect to proximity to the
nuclear power plant is 0.0816.
• This coefficient means that,in an emergency, a 1-unit
increase in proximity (e.g.,defined as 3km in the study)
to a nuclear plant isassociated with life
satisfaction being 0.0816
points lower.

• The estimated coefficient for life
satisfaction impact with respect
to individual income is: 0.3799.
• This coefficient indicates thatthe average income
corresponds to +0.3799 lifesatisfaction points.
• We normalize this coefficient torepresent the average income
required to achieve +1.00 life
satisfaction points, which meansthat 263.23% of average income
is associated with life
satisfaction being 1.00 points
higher.

Total Psychosocial
Impactsof Non-Evacuation($)• Using all theestimations outlined,
the psychosocial costof individuals who are
not evacuated iscalculated bymultiplying themonetized decrease inlife satisfaction by the
total incomes for thepopulation to calculate
the total psychosocial
cost for individuals notevacuated following aRN emergency. 9{Classification}

Estimating the Psychosocial Impacts of Evacuation
The quantification of the psychosocial impacts in the context of RN emergencies is limited, and summary
measures of the psychosocial impact of evacuation at a detailed level were unavailable at the time of research. As
such, the model estimates the psychosocial impact for evacuation using four main steps:

Component

Estimates of Psychosocial Prevalenceand Impact from Evacuation
Share of Population
Expected toExperience
Depression due toEvacuation(%)

Quality-of-LifeImpact for
Individuals
Experiencing
Depression (Years)

The depression
analysis shows that an
average of 19,000
additional people may
experience
depressions
symptoms per 100,000
people evacuated (i.e.,around 19% of
individuals
evacuated could
experience
depression as aresult of evacuation).1

Monetization
Cost of Qualityof Life Lost
($)

Total
Psychosocial
Impacts ofEvacuation($)

To quantify these
depression impacts,
this model uses
health-adjusted life
expectancy (“HALE”)
estimates. The key
finding used in theanalysis is that
individuals
experiencing
depression from a RNemergency are
expected toexperience 10.6 fewer
years of good health.2

To convert the differences
in HALE for individuals
with and without
depression, the model
uses a standard thresholddollar value for each oneyear loss of HALE. Thiswas set to $50,000 per
year, which is themonetized quality
adjusted life years valuecommonly used in healtheffectiveness studies.3

Using all theestimations
outlined, thepsychosocial cost ofindividuals
evacuatedcombines all thefindings to calculate
the total
psychosocial costfor individuals
evacuated following
a RN emergency.

2. Steensma et al., (2016)

3. Canadian Agency for Drugs and Technologies in Health (CADTH)

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1. U.S. NRC (2021)

Accounting for Radiological Impacts{Classification}

Based on the sievert reference levels from ICRP and the USNRC monetization of the radiological consequences
associated with exposure, this model estimates the monetized detriment for each population group around a
nuclear facility. To note, the model currently assumes that individuals who are evacuated are not exposed toradiation.1 The monetized detriment is a function of:Component

Estimates of FSA RadiologicalExposure

Projected Dose(Millisieverts)
The projected dose isa function of distanceto the power plant.
Following current
guidance, theestimatedmillisieverts in thecase study model is
set at 100 for
distances less than
20 kms from thenuclear power plant.

1.
2.

Monetization

Total Population
Within a Given
FSA

The Monetizationof Exposure
($)

Total
Monetized
Detriment

The larger a
population within agiven FSA, the larger
the total radiologicalimpact.

The model relies on 2014
dollar-per-rem estimatesfrom the U.S. NRC tomonetize the healthrelated consequences
associated withradiological exposure• These estimates are
based on the value of astatistical life and anominal risk coefficientfor stochastic healtheffects from radiation
exposure.2

Multiplying
thesecomponents
togetherprovides anestimate of theradiologicalimpact for agiven FSAThis is a simplifying assumption; however, with additional information from Health Canada or from a real RN emergency, this assumption can be adjusted.
In the context of this model, three steps were required to update the U.S. NRC estimates. First, the value of a statistical life provided by the Treasury Board of CanadaSecretariat was inflated to the relevant year of analysis (i.e., 2020). Second, the value of a statistical life was multiplied by the nominal risk coefficient provided by the U.S.
NRC to obtain per person-rems. Finally, per-person-rem units were converted to millisieverts using the relationship that 1 rem is equivalent to 10 millisieverts.

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Approach to Comparing Psychosocial and Radiological Costs
The net evacuation cost per person compares the total costs (i.e., radiological and psychosocial) of evacuationand non-evacuation for a given population group
The net evacuation impact subtracts the total cost (i.e., psychosocial and radiological) of evacuation from thetotal cost of non-evacuation and divides these costs by the total population within the relevant geographic area.

Cost of Non-Evacuation

Cost of Evacuation

Total Psychosocial
Impactsof Non-Evacuation($)

Total Psychosocial
Impacts ofEvacuation
($)

Total
Monetized Detrimentfor individuals NotEvacuated

Total
Monetized
Detriment forindividuals
Evacuated

Net Evacuation Impact

If positive, nonevacuation costs aregreater thanevacuation costs. If
negative, nonevacuation costs areless than evacuation
costs.
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Results
When model inputs are set to their guidance levels, the results show that evacuation is lesscostly for 15 out of 97 FSAs within a 57-kilometer radius to the nuclear facility, or 12.3% of thepopulation within that radius
Net Evacuation Impact for Each Forward Sortation Level
Net-Evacuation Impact Per Person [$000s]
Bubble Area = Population Size
Net-Evacuation Impact Per Person for Each Forward
Sortation Area (QALY 100k)

Net-Evacuation Impact Per Person for Each Forward
Sortation Area (QALY 50k)
$150

$50

Distance from
Nuclear Facility (km)Net-Evacuation
Impact Above $0 =Evacuation lessCostly

$100

$50

$00

Distance from
Nuclear Facility (km)

$0

1020

30

40

50

60

70

-$50

-$100

0

1020

30

40

50

60

70

-$50

-$150

-$100

-$200

-$150

-$250

Net-Evacuation
Impact Above $0 =Evacuation lessCostly13

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Impact of Key Model Parameters on Net-Evacuation Cost (1/2)
Changing the model’s key parameters will impact the relative cost of evacuation and non-evacuation
Life Satisfaction: The estimated change in life satisfaction associated with a nuclear emergency for
individuals not evacuated. Note, this parameter is negative in this context. Hence, an increase refers to asmaller negative number and a decrease refers to a greater negative number.

Change in Net-Evacuation Impact

An Increase in Life Satisfaction
post-RN emergency (or more
specifically, a smaller loss oflife satisfaction)
Leads toA decrease in the cost of
non-evacuation

A decrease in the netevacuation impact ofevacuation, implying that
evacuation is now
relatively more costly

Depression Prevalence: Depression prevalence is the main variable driving the psychosocial
impact of evacuation. It is the estimated share of individuals expected to experience depression
from evacuation.

An Increase in the number ofindividuals expected to experience
depression due to evacuation…

An Increase in the costof evacuation

Leads toA decrease in the net
evacuation impact,
implying that evacuation
is now relatively morecostlyMonetary Value of a QALY: The estimated willingness to pay for a full year of life, which entersthe model as a negative cost associated with lost quality of life for depression.

An Increase in monetary value ofa QALY…

Leads toAn Increase in the costof evacuation

A decrease in the netevacuation impact,
implying that evacuation
is now relatively morecostly14

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Impact of Key Model Parameters on Net-Evacuation Cost (2/2)
Changing the model’s key parameters will impact the relative cost of evacuation and non-evacuation

Income: The total income of income recipients in an FSA divided by thetotal population.
An Increase in income perperson impacted by theemergency…
Leads toAn Increase in the costof non-evacuation

Leads toProjected Dose: The effective or equivalent radiation dose that would beexpected to be received if protective actions were not taken.
An Increase in theeffective dose…

An Increase in the costof non-evacuation
Leads toLeads toChange in Net-Evacuation
ImpactAn increasein the net
evacuation
impact,implying that
evacuation isnow
relatively lesscostlyAn increase inthe net
evacuation
impact, implyingthat evacuation
is now relatively
less costly15Preliminary Results – Sensitivity Analysis{Classification}

When using the upper and lower bounds of the life satisfaction impact estimate,this yields evacuation estimates in the range of 11.7% to 20% of the population;
the range of outcomes for depression prevalence is narrower
A sensitivity analysis was performed on the
net-evacuation impacts per person for thelife satisfaction and depression prevalence
parameters.

Net Evacuation Impact – Sensitivity Analysis
Net-Evacuation Impact Per Person [$000s]

Life Satisfaction:•When using the upper bound of life
satisfaction (i.e., a higher loss of life
satisfaction), it is less costly to evacuateroughly 20.0% of the population within 57
kilometres.
•When using the lower bound estimate oflife satisfaction (i.e., a lower loss of life
satisfaction for individuals not evacuated),
it is less costly to evacuate roughly 11.7%of the population.
Depression Prevalence:•
When using the upper bound (i.e., higher
depression prevalence), it is less costly toevacuate approximately 11.7% of thepopulation.
•On the other hand, it is less costly toevacuate 17.3% of the population within 57
kilometres when using the lower bound ofdepression prevalence.
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What can we do with the tool as is?

• Proof of concept for a decision tool to balanceradiological and psychosocial detriment• Contribution to evidence-based guidance on ajustified and optimised protection strategy thatconsiders psychosocial impacts• Improved risk communications tools

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Summary for discussion• The development of a non-radiological sievert forpsychosocial detriment from protective actions requires
future research• Psychosocial impacts measured with general andsummary indicators are interrelated and cannot besummed• Individual psychosocial impacts can be measured andcompared to radiological impacts• A single measured psychosocial impact (depression) canhave a very significant impact• These tools are needed to justify and optimize decision
making in nuclear emergencies• What needs to be added/improved so that this tool could
be implemented?
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