Lead radionuclides

Chapter 6 was concerned, with determining the probability of various failures leading to insufficient core cooling of a nuclear reactor. This chapter describes how the accident effects are calculated as the accident progresses from radionuclide release, radionuclide migration within the plant, escape from retaining structures, atmospheric radionuclide transport and the public health effects. 

The retention of radionuclides within the containment was little accounted for by the RSS, but ranges from little to very substantial because of agglomeration and deposition. This leads to a large over prediction of the iodine risk, but substantial agreement with RSS for some other isotopes. 

Even where low nickel alloys are specified, corrosion, however limited, may lead to the release of other alloying components and the release of more radionuclides such as chromium51, cobalt58, iron59, and manganese54. Thus, materials selection remains a critical issue in nuclear plant SG design. 

The role of radionuclides as tracer of the chemical transport in river is also reinforced by the fact that each of the U-Th-Ra elements has several isotopes of very different half-lives belonging to the U-Th radioactive series. Thus, these series permit comparison of the behavior of isotopes of the same element which are supposed to have the same chemical properties, but very different lifetimes. These comparisons should be very helpful in constraining time scales of transport in rivers. This was illustrated by Porcelli et al. (2001) who compared ( " Th/ U) and ( °Th/ U) ratios in Kalix river waters and estimated a transit time for Th of 15 10 days in this watershed. The development of such studies in the future should lead to an important progress in understanding and quantifying of transport parameters in surface waters. This information could be crucial for a correct use of U-series radioactive disequilibria measured in river waters to establish weathering budgets at the scale of a watershed. 

Volchok, H. L., Toonkel, L. and Schonberg, M. (1976). "Radionuclides and lead in surface air, page B-l in USERDA Health and Safety Laboratory Environmental Quarterly, September 1, 1975 Through December 1, 1975, Report No. HASL-298, Appendix (National Technical Information Service, Springfield, Virginia). 

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