A review of techniques for parameter sensitivity analysis of environmental models

Mathematical models are utilized to approximate various highly complex engineering, physical, environmental, social, and economic phenomena. Model parameters exerting the most influence on model results are identified through a ‘sensitivity analysis’. A comprehensive review is presented of more than a dozen sensitivity analysis methods. This review is intended for those not intimately familiar with statistics or the techniques utilized for sensitivity analysis of computer models. The most fundamental of sensitivity techniques utilizes partial differentiation whereas the simplest approach requires varying parameter values one-at-a-time. Correlation analysis is used to determine relationships between independent and dependent variables. Regression analysis provides the most comprehensive sensitivity measure and is commonly utilized to build response surfaces that approximate complex models.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42691/1/10661_2004_Article_BF00547132.pd

Land and water use characteristics in the vicinity of the Savannah River Site

Routine operations at the Savannah River Site (SRS) result in the release of small amounts of radionuclides to the atmosphere and to the Savannah River. The resulting radiological doses to the offsite maximum individual and the offsite population within 50 miles of the SRS are estimated on a yearly basis. These estimates are generated using dose models prescribed for the commercial nuclear power industry by the Nuclear Regulatory Commission (NRC). The NRC provides default values for dose model parameters for facilities not having enough data to develop site-specific values. A survey of land and water use characteristics for the Savannah River area has been conducted to determine as many site-specific values as possible for inclusion in the dose models used at the SRS. These site parameters include local characteristics of meat, milk, and vegetable production; river recreational activities; and meat, milk, and vegetable consumption rates. The report that follows describes the origin of the NRC default values, the methodology for deriving regional data, the results of the study, and the derivations of region-specific usage and consumption rates. 33 refs., 3 figs., 8 tabs

Gaussian dispersion and dosimetric modeling sensitivity to area-specific 1982--86 meteorological data collected at the Savannah River Site

Radiological dose to the offsite maximum individual or the 50-mile population is often estimated assuming that operational atmospheric releases originate from the geographical center of the Savannah River Site. Historically, meteorological data collected from instrumentation on the H-Area tower have been utilized to estimate atmospheric dispersion from centrally located releases.'' This paper examines the effect on dose predictions using meteorological data from seven onsite towers located at A, C, D, F, H, K, and P areas to describe meteorological conditions at the central release location. Maximum individual dose estimates using both annual and short-term average air concentrations are well within 20% of the mean prediction. Population dose estimates are also within 20% of the mean prediction. Population dose estimates are also within 20% of the mean except for two-hour doses using H-Area meteorological data, which is less than the average estimate by about 30%

Tritium in the Savannah River Site environment

Tritium is released to the environment from many of the operations at the Savannah River Site. The releases from each facility to the atmosphere and to the soil and streams, both from normal operations and inadvertent releases, over the period of operation from the early 1950s through 1988 are presented. The fate of the tritium released is evaluated through environmental monitoring, special studies, and modeling. It is concluded that approximately 91% of the tritium remaining after decay is now in the oceans. A dose and risk assessment to the population around the site is presented. It is concluded that about 0.6 fatal cancers may be associated with the tritium released during all the years of operation to the population of about 625,000. This same population (based on the overall US cancer statistics) is expected to experience about 105,000 cancer fatalities from all types of cancer. Therefore, it is considered unlikely that a relationship between any of the cancer deaths occurring in this population and releases of tritium from the SRS will be found

Background information for the PAR Pond safety and health hazard analysis

The baseline risk assessment [WSRC91] has demonstrated that the hazard at PAR Pond is solely from external exposure to Cs-137, a gamma emitting radionuclide. Between 1954 and 1964, approximately 222 curies of radioactive cesium (Cs-134 and Cs-137) were released to the Lower Three Runs Creek system from R Reactor [Ma9l]. These releases were associated with leaking fuel and target slugs in the reactor disassembly basin. Independent studies show that approximately 45 curies of Cs-137 (half-life of 30 years) still resides in the sediments of PAR Pond [Wh9l; Wi9l]; Cs-134 has a relatively short half-life (2 years) and has decayed to insignificant quantities since it was released