A Multiple-Objective Decision Analysis for Terrorism Protection. Potassium Iodide Distribution in Nuclear Incidents

Table of content

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Abbreviation register

1. Introduction

2. Potassium Iodide (KI)

3. Background
3.1. Chernobyl nuclear power plant
3.2. Latest nuclear accident in Fukushima

4. Multiple-objective decision analysis for terrorism protection - key insights and main goals

5. Multiple-objective decision analysis process
5.1. Decision Analysis in general
5.2. Multiple-objective decision analysis in general
5.3. Multiple-objective decision analysis for KI distribution
5.3.1. Characteristics ofthe decision problem
5.3.2. Objectives Hierarchy
5.3.3. Single-Attribute Value Functions
5.3.4. Weighs of the objectives
5.3.5. Value gaps
5.3.6. Alternatives
5.3.7. Evaluation and decision

6. Sensitivity Analysis
6.1. Sensitivity analysis in general
6.2. Tailor made analysis to specific contexts
6.3. One-Way Sensitivity Analysis
6.4. Two-Way Sensitivity Analysis

7. Decision under uncertainty: A decision tree model

8. Similar studies

9. Conclusion

List of book references

List of internet references

Table register

Table 1: Percent Thyroid Protection from radioiodine after a single 130 mg dosage ofKI

Table 2: Rating scales example

Table 3: Value gaps example

Table 4: Alternative plan for the KI decision problem

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Figure 1: Multiple-Objective Decision Analysis Approach

Figure 2: Multiple-Objective Decision Analysis Approach

Figure 3: Evaluating the alternatives

Figure 4: Evaluation of alternatives

Figure 5: One-Way Sensitivity Analysis on Raw Swing Weight of„Availability“ Objective

Figure 6: One-Way Sensitivity Analysis onNormalized Weight of„Education“ Objective.

Figure 7: Two-Way Sensitivity Analysis on the „Availability“ Objective and the „Education“ Objective in the KI Decision Problem

Figure 8: Decision tree for KI distribution

Abbreviation register

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1. Introduction

This decision analysis was compiled in order to qualitatively and quantitatively assess the different possible potassium iodide (KI) distribution methods for a hypothetical local region. The possibility of the release of radioactive iodine caused by nuclear accidents or terrorist actions makes it crucial to come up with the best distribution methods of KI in order to protect people against thyroid cancer. (Feng and Keller (2006), p. 76-93)

2. Potassium Iodide (KI)

Potassium Iodide, called also „KI“ is a salt of stable and not radioactive iodine needed by human body to create thyroid hormones. This kind of chemical is of crucial importance in case of any human exposure to radioactive iodine either by a nuclear accident/incident, the detonation of nuclear weapons or other terrorist actions. It is an effective way to protect population from the risk of thyroid cancer. There are some reasons, why KI instead of other chemicals are used. KI is inexpensive, stable, and readily available with a long-shelf life if stored properly in dry and shady places. In case of any radiological or nuclear event, radioactive iodine may get into the air and be breathed by local population into the lungs or it may also contaminate food and water and get into the human body otherwise. As a result the contamination of human body by radioactive iodine is called „internal contamination44. Large amounts of radioiodine can be responsible for the thyroid cell death because of radioiodine's beta radiation. The radioactive iodine may be absorbed by the gland and cause fatal injuries to it. By taking KI, the stable iodine, in any nuclear accident, the gland absorbs the non­radioactive iodine. The gland becomes full of non-radioactive iodine and will not be able to absorb any more radioactive iodine from the disaster area thus protecting the gland from the risk of thyroid cancer. (National Research Council (2004), p. 19; REMM 2011)

Furthermore it seems very crucial to mention that iodine is a very important part of thyroid hormones and some mental destructions, retardation or cretinism is caused by the deficiency of iodine. Therefore an accurate intake of iodine is a general public goal. The most efficient way how to provide iodine to the public is through the use of iodized salt. As this is not possible in every area of the world, there are other possible methods, such as the ingestion of iodizes oil, iodination of the central water system, addition of iodine to the animal feed, etc.

The probable low dietary iodine intake in Ukraine Chernobyl led to the increased uptake of radioiodine. (National Research Council (2004), p. 16-17)

However KI does not always offer complete protection against thyroid cancer. The success of how well KI blocks radioactive iodine from entering the human gland depends on various circumstances. Firstly, the time span between the contamination of the environment with the radioactive iodine and taking of KI, are essential. The sooner the KI is taken, the better the drug action. As well as this, the time of absorbing the medicine into the blood needs to be taken into account. Finally, the amount of radioactive iodine released into the environment to which population is exposed, substantially influences the success of the KI medicine. The lower the radiation the higher possibility of KI protection. Besides of these facts, KI is able to protect the human body only against thyroid cancer but not against any other types of cancer or illnesses caused by high doses of radiation. (REMM 2011)

The table 1 below describes the connection between the time when the KI is taken and the protection granted by the drug. By administration of 30-200 mg of stable iodine in form of KI short while before or a few minutes after the nuclear accident the uptake of radioiodine into the gland can be blocked for at least 24 hours. The table shows, that even if KI is taken 8 hours after exposure to radioiodine, the normal uptake of 28 % of radioactive iodine, will be reduced by 40 % to an uptake of approx. 16 %. (National Research Council (2004), p. 20-21)

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Source: National Research Council (2004), p. 21

The most vulnerable members of the population as far as thyroid cancer is concerned are unborn children, infants, young children up to 18 years, pregnant and breastfeeding woman and people with low stores of iodine in their gland. Adults older than 40 years have the lowest risk of thyroid injury. Therefore, they should only take KI when instructed by public health officials and when the radioactive contamination is very high. (REMM 2011)

3. Background

The most serious historical chemical releases of the radioiodine were in the nuclear processing plant of Hanford (1940), in the Russian plant Mayak (1940 and 1950), by testing the atmospheric nuclear weapons in 1950 and 1960 as well as by the nuclear reactor casualties in the United Kingdom (Windscale) in 1957 and the former Soviet Union power plant Chornobyl (also known as „Chernobyl“), which will be further described in more detail. The latest nuclear disaster happened in Fukushima (Japan) in March 2011. The Chernobyl disaster is considered by the many experts and the general public to be one of the most serious nuclear catastrophes associated with many harmful consequences. (National Research Council (2004), p. 9; World Nuclear Association 2012)

3.1. Chernobyl nuclear power plant

The Chernobyl nuclear accident in April 1986 in Ukraine was the one and only disaster in the history of commercial nuclear power with radiation-related fatalities. This nuclear disaster was responsible for the largest uncontrollable release of the radioactive iodine into the environment with substantial health, social and economic impact. A number of human errors in combination with the violation of operating rules of the plant, flawed Soviet reactor design, inadequately trained personnel are mentioned to be some of the reasons that caused the disaster. In addition to this the Chernobyl accident is called to be a direct consequence of Cold War and the lack of any safety culture. (World Nuclear Association 2012)

The Chernobyl accident is known as the explosion and destruction of the Chernobyl 4 reactor. During the first three months after the disaster 30 power plant operators and firemen died. One person was killed immediately because of the explosion and another worker died in hospital that day. Acute radiation syndrome (ARS) was diagnosed in more than 237 cases and 28 people out of these died within a few weeks after the accident as a result of ARS. Between 1987 and 2004 another 19 people died. However it has not been proved that these deaths or other mortality or morbidity in the affected area of Belarus, Russia and Ukraine in the next years have occurred because of the Chernobyl disaster. According to the report of the UN Chernobyl Forum Expert Group: ,,With the exception of thyroid cancer, direct radiation- epidemiological studies performed in Belarus, Russia and Ukraine since 1986 have not revealed any statistically significant increase in either cancer morbidity or mortality induced by radiation“. (Bennett, Repacholi, Carr (2006), p.106) On the other hand, the experts admitted that there was a large increase in child thyroid cancer because of the radiation. Fortunately, the early diagnosis made it possible to avert mortality in many cases. (World Nuclear Association 2012)

3.2. Latest nuclear accident in Fukushima

On 11th March 2011 a major earthquake causing approx. 15 meters high tsunami waves was responsible for the shutdown of the cooling and the power supply function of the three Fukushima Daiichi reactors. This resulted in the Fukushima nuclear disaster.

This nuclear accident was not as serious as at the Chernobyl power plant, but it was still responsible for a large number of economic, financial and psychological damage of Fukushima residents and the general public. The extensive release of radionuclides contaminated the air. The population within 20 km radius from the disaster plant needed to be evacuated. Especially residents under 40 years of age must leave the affected area. Local authorities administered stable iodine. The iodine tablets were positioned at evacuation centers. Cleaning up the contaminated water from the reactor became priority. Moreover, there were no radiation casualties (ARS) reported and no harmful health effects were found in 195 345 affected residents living in the vicinity of the Fukushima plant. (World Nuclear Association 2012)

4. Multiple-objective decision analysis for terrorism protection - key insights and main goals

The multiple-objective decision analysis for the distribution of KI in nuclear disasters has been organized by the National Research Council (NRC). A committee of experts, such as thyroid cancer physicians, radioactive safety experts, nuclear power plant safety professionals and experts in emergency management, was managed with the view of working together on a special KI distribution plan for a hypothetical local region. The main aim of the research was to prove how a decision analysis may support health risk assessment and governmental emergency safety plans and help by terrorism protection.

In situations, in which multiple stakeholders with different views, expectations and goals are involved, it seems to be essential to decide on the basis of a multiple-objective decision­modeling. This allows a systematic analysis of a complex situation while taking into account different objectives and opinions. Many of these situations are complicated and associated with serious health and safety outcomes. As well as this, there may be some legal, political, social and resource constraints in the decision process. During the process of multiple- objective decision analysis, the quantification of the performance of each alternative on the targets, is being accomplished. There exist a number of various weighting methods, among which the swing weight method is often used. This weighting method points out the possible performance on an objective, while creating sliders in a Microsoft Excel spreadsheet and moving („swinging“) the weight. (Feng and Keller (2006), p. 77-79)

5. Multiple-objective decision analysis process

5.1. Decision Analysis in general

The purpose of creating a decision analysis results from identifying and analyzing possible strategies of a defined problem area with the main goal of choosing the best possible strategy maximizing the defined utilities. These utilities often differ in the various problem areas which are being evaluated. The decision maker may want to maximize the revenue, minimize the cost or fully ignore them and concentrate on maximizing the probability of surviving or achieving a better quality of life. (Schwartz (2003), p. 486f.) No consideration of the overall revenue or costs is used in the case of serious health risks to the public, e.g. in nuclear incidents. (Feng and Keller (2006), p. 80) Besides of these facts it’s crucial to point out that decision analysis can be used in all kinds of public health care sector, i.e. primary prevention, secondary prevention and tertiary prevention. Primary prevention can be generally described as the reduction of the risk factors, while the secondary prevention concentrates on the early detection and diagnostics. The tertiary prevention includes the therapy and aftercare. (Schwartz et al. (2003), p. 487)

In this above mentioned decision analysis which is dealing with the distribution of KI in nuclear incidents the multiple-objective decision analysis approach using a decision-under­certainty model was applied, which will be described in the next chapter in more detail.

5.2. Multiple-objective decision analysis in general

Every decision model is an abstraction from reality. In some cases simple models with no real input are sufficient, other help to reflect the reality as good as possible. Multiple- objective decision analysis is very useful when having a set of different objectives together with different stakeholders. They help the decision maker to model, analyze, compare and choose the best decision. The multiple-objective decision analysis has anumber of advantages. First of all, the general approach can be used in problem settings that are similar. As well as this, the multiple-objective decision analysis offers flexibility and integrates several stakeholder views in a single model. Moreover it allows to see trade-offs between the stated objectives. (Feng et al. (2008), p. 103)

5.3. Multiple-objective decision analysis for KI distribution

5.3.1. Characteristics of the decision problem

As the KI decision problem is characterized by multiple stakeholders as well as multiple objectives, the multiple-objective decision analysis was used in order to determine the best possible solution. Figure 1 shows the decision analysis approach.

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Source: Own representation with reference to Feng and Keller (2006), p. 79

The illustration begins with identifying the characteristics of a decision problem, such as stakeholders or main focus. Then on the one hand it’s necessary to develop the objectives hierarchy for the KI decision problem and on the other hand to develop single-attribute value functions, which are helpful when assessing the decision problem. The next step is to set weights for the different objectives developed and to identify the value gaps, which means to identify the difference between the no distribution alternative and the ideal situation. Furthermore alternatives are developed in order to achieve the objectives set. Finally the decision maker will need to rate these alternatives and choose the best one.

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