A sensitivity analysis technique for application to deterministic models

An important element of any uncertainty analysis consists of evaluating the sensitivity of the output uncertainty distributions to the input assumptions. These sensitivity analyses require extensive information regarding mathematical correlations between input and output variables which are generally obtained through repeated computer runs of a physical model. However, in predicting uncertainties associated with severe accident sources terms using contemporary methods, techniques must be devised which reduce the need for extensive commutation using large computer codes. The purpose of the current paper is to propose a new method for sensitivity analysis which does not utilize response surface methods, but instead relies directly on the results obtained from the original computer code calculations. 3 refs., 1 fig

Bound states and the Bekenstein bound

We explore the validity of the generalized Bekenstein bound, S <= pi M a. We define the entropy S as the logarithm of the number of states which have energy eigenvalue below M and are localized to a flat space region of width a. If boundary conditions that localize field modes are imposed by fiat, then the bound encounters well-known difficulties with negative Casimir energy and large species number, as well as novel problems arising only in the generalized form. In realistic systems, however, finite-size effects contribute additional energy. We study two different models for estimating such contributions. Our analysis suggests that the bound is both valid and nontrivial if interactions are properly included, so that the entropy S counts the bound states of interacting fields.Comment: 35 page

The Zion integrated safety analysis for NUREG-1150

The utility-funded Zion Probabilistic Safety Study provided not only a detailed and thorough assessment of the risk profile of Zion Unit 1, but also presented substantial advancement in the technology of probabilistic risk assessment (PRA). Since performance of that study, modifications of plant hardware, the introduction of new emergency procedures, operational experience gained, information generated by severe accident research programs and further evolution of PRA and uncertainty analysis methods have provided a basis for reevaluation of the Zion risk profile. This reevaluation is discussed in this report. 5 refs

An introduction to fuzzy set theory with a view to the quantification and propagation of vagueness in probabilistic risk and reliability assessment

SIGLEAvailable from British Library Lending Division - LD:9091.9F(SRD-R--301) / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Reanalysis of Zion risk

As part of the NUREG-1150 efforts, Brookhaven National Laboratory (BNL) has undertaken a risk analysis of Zion Unit 1 adopting the methodology developed at Sandia National Laboratories (SNL) under the Severe Accident Risk Rebaselining Program. Results of the preliminary version of the analysis are reported here. Completion plans for the Zion study are described also

Requantification of the Zion risk profile

In February 1987, a preliminary version of the Zion Study performed at the Brookhaven National Laboratory was published for comment. This analysis provided one of the technical bases for the draft NUREG-1150 document. Since the publication, various comments both upon general technical terms and specific calculational issues were received from industry, the public and various peer review panels. In the light of methodological and modelling deficiencies identified in the draft analysis by both internal and external reviews, extensive modifications to the preliminary Zion study were undertaken in support of the final version of NUREG-1150. The integrated analysis of Zion is a collaborative effort involving Brookhaven National Laboratory (BNL) and Idaho National Engineering Laboratories (INEL). The current paper discusses preliminary results of the requantification efforts in various stages of the Zion back-end analysis performed at BNL. 7 refs., 7 figs., 6 tabs

A Statistical Explanation for Extreme Bids in the House Market

This paper proposes a simple statistical explanation for the phenomenon of extreme bids. During a boom, the housing market regime switches from a single bidder to a multiple bidder environment. The sale price in a multiple bidder auction is the maximum bid and the distribution of maximum bids contains a much higher proportion of extreme bids compared with the distribution of single bidder valuations. While this theory does not preclude behavioural explanations of extreme bids, it does demonstrate that a world free from strategic and idiosyncratic behaviour would not be a world free from extreme bids during boom periods. Therefore, when gauging the impact of strategic or idiosyncratic behaviour (either hypothetically or empirically) one has to measure the effect against a baseline regime where extreme bids are inevitable, not against a world that is free from extreme bids