Lecture 5: Evaluative Methods for Nuclear Non-proliferation and Security

NUCE 304: Evaluative Methods for Nuclear Non-proliferation and Security Reactor Operational Factors and Biological Effects of Radiation Dr. Ahmed Alkaabi 1  Learning Objective Be familiar with the how nuclear reacto...

NUCE 304: Evaluative Methods for Nuclear Non-proliferation and Security Reactor Operational Factors and Biological Effects of Radiation Dr. Ahmed Alkaabi 1  Learning Objective Be familiar with the how nuclear reactors respond to changes Appreciate the consequences of the build up of fission products and transuranics in nuclear power reactors Understand the biological effects of ionizing radiation Take away from this lecture: Major safety aspects of nuclear power plants 2  Changing a Reactor’s Power The reactor power level is Reactor Power Versus Time usually related to the value 3.5 (Σf∙Φ∙V) of k 3 k>1 We will change the value of 2.5 k1 2.5 k 500 rem Gastrointestinal Damage (>5 Sv) > 5000 rem Death Within 2-3 days (> 50 Sv) 53  Chronic Dose A small dose of radiation received over a long period of time. Typical examples are: The dose we receive from natural background The dose from occupational exposure The human body is better equipped to tolerate chronic doses 54  Damage to Tissue Varies Different tissues respond differently to the same radiation dose (or dose equivalent) Particularly important for radioactive material intake, where material may concentrate in particular organs Therefore, compute the “Effective Dose” Dose to each type of tissue is multiplied by a tissue weighting factor and summed Effective dose allows us to compare the risk from one kind of radiation dose to another International standard unit is the Sievert 1 Sievert = 100 rem 55  Dose vs. Dose Rate Dose rate is the rate at which you receive the dose. Units: Gray/hr, mGray/hr, RAD/hr, mRAD/hr. Energy absorbed per unit time. Effective Dose (a measure of tissue damage) is then: “Effective Dose” (Sv or rem) = Dose Rate X Time X Quality Factor X Tissue Weighting Factor Question: How much dose would this individual receive in 15 minutes? Answer: ______ mrem 200 mrem/hr 56  Context 1 milliSievert (1 mSv) = 100 millirem (100 mrem) Avg. US Annual Dose: 620 mrem Avg. Natural Bkgd Denver: Millirem 450 mrem Avg. U.S. Natural Bkgd: 310 mrem 57 57  Cancer Risk Current rate of cancer death is about 20%. An individual who receives 250 millisieverts over a working life increases his/her risk of cancer by 1% to about 21%. The average annual dose to U.S. radiological workers is less than 1 millisievert (40 mSv over working life). 58  References Primary Resources 1. DOE-HDBK-1130-98, CN 1, February 2005, Radiological Worker Training 2. Basic Radiation Protection Technology, 5th Edition, Daniel Gollnick 59  References 1. Lamarsh, J. R., and Baratta, A. J., “Introduction to Nuclear Engineering”, third edition, Prentice Hall, 2001 2. DOE Fundamentals Handbook “Nuclear Physics and Reactor Theory”, http://www.hss.doe.gov/nuclearsafety/ns/techstds /standard/hdbk1019/h1019v1.pdf 3. DOE Fundamentals Handbook “Nuclear Physics and Reactor Theory”, http://www.hss.doe.gov/nuclearsafety/ns/techstds /standard/hdbk1019/h1019v2.pdf 4. Stacey, W. M., “Nuclear Reactor Physics”, second edition, Wiley-VCH, 2007 60  List of Required Texts 1. DOE Fundamentals Handbook “Nuclear Physics and Reactor Theory”, http://www.hss.doe.gov/nuclearsafety/ns/techstds /standard/hdbk1019/h1019v1.pdf 2. DOE Fundamentals Handbook “Nuclear Physics and Reactor Theory”, http://www.hss.doe.gov/nuclearsafety/ns/techstds /standard/hdbk1019/h1019v2.pdf 61