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Title: Screening Thresholds/Probabilities.


Abstract not provided.

Publication Date:
Research Org.:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
Report Number(s):
DOE Contract Number:
Resource Type:
Resource Relation:
Conference: Proposed for presentation at the Safety Factor Discussion held May 1 - June 1, 2017 in Nashville, TN.
Country of Publication:
United States

Citation Formats

Pasik, Michael F. Screening Thresholds/Probabilities.. United States: N. p., 2017. Web.
Pasik, Michael F. Screening Thresholds/Probabilities.. United States.
Pasik, Michael F. Mon . "Screening Thresholds/Probabilities.". United States. doi:.
title = {Screening Thresholds/Probabilities.},
author = {Pasik, Michael F.},
abstractNote = {Abstract not provided.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon May 01 00:00:00 EDT 2017},
month = {Mon May 01 00:00:00 EDT 2017}

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  • How does one address the question of what level of environmental contamination causes adverse effects in plants and wildlife based solely on information from the ecotoxicology literature? One is confronted with a database derived from studies conducted in different laboratories, with different protocols, on different species that address different toxicity endpoints. Rarely will this information be directly applicable to the species of interest. How then are priorities set to sort the literature data in order of relevance to needs? Using decision analysis theory in an analytical hierarchy procedure the authors queried a panel of experts to define which components ofmore » a study make it more or less applicable to determining toxicity thresholds for organisms in their natural environment. A questionnaire guided them through a series of pairwise comparisons that enabled them to rank the importance of study duration, endpoint, and other reported variables. Each study from the literature can then be ranked according to the relative weights given to each of the categories and its usefulness determined for setting threshold values for a species of interest.« less
  • Ecological risk assessments (ERA) in the Superfund program require USEPA to estimate the likelihood that adverse effects will occur as a result of exposure to the release of a hazardous substance (OSWER Dir. No. 9285.7-17, Aug 12, 1994). The Superfund ERA process encourages using a preliminary risk calculation (PRC) to determine which of the many contaminants found on-site may pose a threat to ecological receptors. A hazard quotient is used in the PRC to compare site concentrations to ecotoxicological benchmarks. Exceeding the benchmark indicates the need for further site investigation and focuses the attention of the assessment on the appropriatemore » chemicals of concern. The Superfund program has produced a list of ecotoxicological benchmarks, called Ecotox Thresholds (ETs). Methods developed by other USEPA programs and other governmental agencies were used to generate media specific (soil, water and sediment) concentrations deemed to be protective for ecological receptors. For those contaminants whose toxicity is governed by media-specific physical/chemical properties (pH, hardness, etc.), software has been developed to generate site-specific ET values. Ecotox Thresholds provide the Superfund program with an efficient and consistent tool to evaluate ecological risks.« less
  • It has recently been reports that Table A.1 of Attachment 1 of DOE STD-1027-92 is being improperly used to determine the Category 3 inventory threshold values for non-reactor nuclear facilities. The concern of this paper is that Safety Analysts and Facility Managers at the Lawrence Livermore National Laboratory (LLNL), as well as at other locations in the DOE Complex, are improperly using the entries in Table A.1. It is noted at this point that the common use of this table is to establish the lower thresholds for both Categories 2 and 3 non-reactor nuclear facilities by considering inventory quantities, asmore » opposed to a postulated accident scenario. This paper will provide insight regarding this error and will show that the error is most likely non-conservative in nature.« less
  • Screening effects for transition probabilities in collisions of charged particles with an atom or stripped ion are investigated using the modified hyperbolic-orbit path in the semiclassical approximation. Effective nuclear charges for bound electrons in many-electron atoms are determined by new screening constants [Y.-D. Jung and R. J. Gould, Phys. Rev. A 44, 111 (1991)]. Applications were made to O, O[sup 4+], and O[sup 7+]. For these targets, the transition probabilities are calculated for 1[ital s][r arrow]2[ital p] transitions. The results show that the maximum point of the transition probability is shifted to the nucleus with an increase of the screeningmore » effect. Moreover, the maximum amplitude of the transition probability is appreciably reduced as the screening effect increases.« less