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in subjects: "Reactivity"

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Assessment of light water reactor fuel damage during a reactivity initiated accident

This paper presents an assessment of LWR fuel damage during a reactivity initiated accident and comments on the adequacy of the present USNRC design requirements. Results from early SPERT tests are reviewed and compared with results from recent computer simulations and PBF tests. A progression of fuel rod and cladding damage events is presented. High strain rate deformation of relatively cool irradiated cladding early in the transient may result in fracture at a radial average peak fuel enthalp… more

Date: January 1, 1980

Creator: MacDonald, P. E.; Seiffert, S. L.; Martinson, Z. R.; McCardell, R. K.; Owen, D. E. & Fukuda, S. K.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Source-jerk analysis using a semi-explicit inverse kinetic technique

A method is proposed for measuring the effective reproduction factor, k, in subcritical systems. The method uses the transient response of a subcritical system to the sudden removal of an extraneous neutron source (i.e., a source jerk). The response is analyzed using an inverse kinetic technique that least-squares fits the exact analytical solution corresponding to a source-jerk transient as derived from the point-reactor model. It has been found that the technique can provide an accurate means… more

Date: January 1, 1985

Creator: Spriggs, G.D. & Pederson, R.A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Transport-diffusion comparisons for small core LMFBR disruptive accidents

A number of numerical experiments were performed to assess the validity of diffusion theory for calculating the reactivity state of various small core LMFBR disrupted geometries. The disrupted configurations correspond, in general, to various configurations predicted by SAS3A for transient undercooling (TUC) and transient overpower (TOP) accidents for homogeneous cores and to the ZPPR-7 configurations for heterogeneous core. In all TUC cases diffusion theory was shown to be inadequate for the c… more

Date: November 1, 1977

Creator: Tomlinson, E.T.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Feynmann variance-to-mean method

The Feynmann and other fluctuation techniques have been shown to be useful for determining the multiplication of subcritical systems. The moments of the counting distribution from neutron detectors is analyzed to yield the multiplication value. We present the methodology and some selected applications and results and comparisons with Monte Carlo calculations.

Date: January 1, 1985

Creator: Dowdy, E. J.; Hansen, G. E. & Robba, A. A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Ferrocyanide-containing waste tanks: Ferrocyanide chemistry and reactivity

The complexing constant for hexacyano-iron complexes, both Fe(2) and Fe(3), are exceptionally large. The derived transition metal salts or double salts containing alkali metal ions are only slightly soluble. The various nickel compounds examined in this study, i.e., those predicted to have been formed in the Hanford waste scavenging program, are typical examples. In spite of their relative stability towards most reagents under ambient conditions, they are all thermodynamically unstable towards … more

Date: September 1, 1991

Creator: Scheele, R. D.; Burger, L. L.; Tingey, J. M.; Bryan, S. A.; Borsheim, G. L.; Simpson, B. C. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Improved reactivity monitor using a shuttling /sup 252/Cf source

A technique for measuring reactivities of moderated arrays of nuclear fuels with a shuttling /sup 252/Cf source has been significantly extended and refined. In the old method, the shuttle time was so short that details of the delayed neutron time behavior could be neglected. Specifically, the average delayed neutron population during the ''On'' part of the cycles was assumed to be equal to that during the ''Off'' part. In the new method, the detailed behavior of the delayed neutrons is explicit… more

Date: January 1, 1977

Creator: Baumann, N.P. & Jarriel, J.L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Comparative analysis of internal fuel motion in annular fuel designs

In this paper, the whole-core reactivity consequences of internal fuel motion in three annular fuel designs during a hypothetical 3 dollars/s transient overpower (TOP) accident are compared to determine the effect of geometric design variations. The PINEX-2 and PINEX-3 experiments were performed in the TREAT reactor using annular fuel pins irradiated in GETR. This paper investigates three combinations of solid and annular axial blankets and fission gas plena: top annular blanket and plenum, bot… more

Date: September 16, 1983

Creator: Smith, D. E.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Review of physics methodology of ATR safety analysis

At the request of EG G Idaho, the Pacific Northwest Laboratory (PNL) performed a brief review of the physics methods employed in the safety analyses for the Advanced Test Reactor. PNL determined that the general approach used by EG G was sound. Comparisons were made between the EG G results and a simplified PBL model. These demonstrated good agreement. However, the lack of spacial treatment of the moderator density reactivity coefficient and exclusion of the test loops from the reactivity model… more

Date: September 1, 1991

Creator: Little, W.W. & Heaberlin, S.W.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Comparison of eigenvalue computations for the Savannah River K Reactor using 5 and 7 digit dimensional and isotopic quantities

A study was undertaken to characterize the reactivity temperature coefficient (RTC) behavior for the Savannah River K-Reactor pursuant to the safety review mandated by the Department of Energy (DOE) in August 1988. During the course of the investigation, it was found that the accuracy levels required in dimensional and isotopic quantities at elevated temperatures were much greater than was initially supposed and are typically used in reactor neutronics calculations. The codes involved do not au… more

Date: January 1, 1991

Creator: Durkee, J.W. Jr.; Mosteller, R.D.; Perry, R.T. & Sapir, J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

A simple model for radial expansion reactivity in LMRs (liquid metal reactors)

Presented in this report is a simple analytical model developed for evaluating the radial expansion reactivity in small modular liquid metal reactors (LMRs). The present model is based on a non-leakage representation of the effective neutron multiplication factor. The resultant analytical expression for the radial expansion reactivity is simple and can be used directly in a system code for safety analyses. Applications of the present model to PRISM and SAFR resulted in a good agreement with the… more

Date: January 1, 1988

Creator: Cheng, H.S. & Van Tuyle, G.J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

PRD (power-reactivity-decrement) components of a homogeneous U10Zr-fueled 900 MWt LMR

The linear and Doppler feedback components of the regional contributions of the power-reactivity-decrement (PRD) for a representative 900 MWt homogeneous U10Zr-fueled sodium-cooled reactor are calculated. The PRD is the reactivity required to bring the reactor from zero-power hot-critical condition to a given power level. These components are further separated into power dependent and power-to-flow dependent parts. The values are compared with corresponding quantities calculated for the Experim… more

Date: January 1, 1988

Creator: Meneghetti, D. & Kucera, D.A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

A Mechanism Explaining the Instability of EBR-I, Mark III

Presented at the International Atomic Energy Agencysponsored Seminar on the Physics of Fast and Intermediate Reactors. Vienna, August 3-11, 196l. A feedback model, was developed to account for resonant instabilities in the Mark II core. In this model, the prompt positive power coefficient effect is ascribed to fuel rod bowing and the delayed negative power coefficient effect to thermally lnduced motions in the lower shield plate. Since this model is supported by observations, it is concluded th… more

Date: September 1, 1961

Creator: Smith, R. R.; Matlock, R. G.; McGinnis, F. D.; Novick, M. & Thalgott, F. W.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Comparative sodium void effects for different advanced liquid metal reactor fuel and core designs

An analysis of metal-, oxide, and nitride-fueled advanced liquid metal reactor cores was performed to investigate the calculated differences in sodium void reactivity, and to determine the relationship between sodium void reactivity and burnup reactivity swing using the three fuel types. The results of this analysis indicate that nitride fuel has the least positive sodium void reactivity for any given burnup reactivity swing. Thus, it appears that a good design compromise between transient over… more

Date: July 1, 1991

Creator: Dobbin, K. D.; Kessler, S. F.; Nelson, J. V.; Gedeon, S. R. & Omberg, R. P.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Assessment of molten debris freezing in a severe RIA in-pile test. [PWR; BWR]

An understanding of the freezing of molten debris on cold core structures following a hypothetical core meltdown accident in a light water reactor (LWR) is of importance to reactor safety analysis. The purpose of the present investigation was to analyze the transient freezing of the molten debris produced in a severe reactivity initiated accident (RIA) scoping test, designated RIA-ST-4, which was performed in the Power Burst Facility and simulated a BWR control rod drop accident. In the RIA-ST-… more

Date: January 1, 1980

Creator: El-Genk, Mohamed S. & Moore, Richard L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Pulsed reactivity measurements of large /sup 235/U--Al castings in H/sub 2/O

The safe storage and handling of large /sup 235/U-Al castings at the Savannah River Plant are assured by limiting the number of fuel pieces and their spacing such that the k/sub eff/ calculated by KENO-IV with Hansen-Roach cross sections does not exceed some conservative limit with complete, accidental water immersion. For economic reasons, the conservative limit on the calculated k/sub eff/ is generally chosen as high as possible consistent with an accurate knowledge of the margin of error in … more

Date: January 1, 1977

Creator: Pellarin, D.J. & Jarriel, J.L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Effects of subcooling and rod drop speed on the BWR rod drop accident

The techniques and models used in the analysis of the control rod drop accident (CRDA) in a BWR have ranged from approximate conservative methods with a simple feedback model to detailed representations of the thermal-hydraulic and neutronic mechanisms. In a recent paper Cheng and Diamond presented a detailed evaluation of the CRDA and the effects of varying a number of important accident parameters. Their calculations performed with the BNL-TWIGL core dynamics code, have shown that the effect … more

Date: January 1, 1982

Creator: Cokinos, D.; Carew, J. & Aronson, A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

The ultimate safe (US) Reactor: A concept for the third millenium

The Ultimate Safe (U.S.) Reactor is based on a novel safety concept. Fission products in the reactor are allowed to accumulate only to a level at which they would constitute a harmless source term. Removal of fission products also removes the decay heat - the driving force for the source term. The reactor has no excess criticality and is controlled by the reactivity temperature coefficient. Safety is inherent and passive. Waste is removed from the site promptly.

Date: January 1, 1986

Creator: Gat, U.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Sodium Loop Safety Facility W-2 experiment fuel pin rupture detection system. [LMFBR]

The objective of the Sodium Loop Safety Facility (SLSF) W-2 experiment is to characterize the combined effects of a preconditioned full-length fuel column and slow transient overpower (TOP) conditions on breeder reactor (BR) fuel pin cladding failures. The W-2 experiment will meet this objective by providing data in two technological areas: (1) time and location of cladding failure, and (2) early post-failure test fuel behavior. The test involves a seven pin, prototypic full-length fast test re… more

Date: May 1, 1980

Creator: Hoffman, M. A.; Kirchner, T. L. & Meyers, S. C.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Scoping systems analysis of a 350 MWt modular liquid metal cooled reactor

The systems analysis code SASSYS was used to explore the sensitivity of the system response to various inherent reactivity feedback mechanisms and design features for a small, liquid-metal-cooled reactor during the first 1000 s following the initiation of an unprotected loss-of-flow and/or loss-of-primary-heat-removal transient. The results show that to maximize the inherent safety of small, liquid-metal-cooled reactors, inherent feedback mechanisms should be accounted for in establishing desig… more

Date: January 1, 1985

Creator: Morris, E. E.; Rhow, S. K. & Switick, D. M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

ORNL analyses of AVR performance and safety

Because of the high interest in modular High Temperature Reactor performance and safety, a cooperative project has been established involving the Oak Ridge National Laboratory (ORNL), Arbeitsgemeinschaft Versuchs Reaktor GmbH (AVR), and Kernforschungsanlage Juelich GmbH (KFA) in reactor physics, performance and safety. This paper presents initial results of ORNL's examination of a hypothetical depressurized core heatup accident and consideration of how a depressurized core heatup test might be … more

Date: January 1, 1985

Creator: Cleveland, J.C.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Summary of advanced LMR (Liquid Metal Reactor) evaluations: PRISM (Power Reactor Inherently Safe Module) and SAFR (Sodium Advanced Fast Reactor)

In support of the US Nuclear Regulatory Commission (NRC), Brookhaven National Laboratory (BNL) has performed independent analyses of two advanced Liquid Metal Reactor (LMR) concepts. The designs, sponsored by the US Department of Energy (DOE), the Power Reactor Inherently Safe Module (PRISM) (Berglund, 1987) and the Sodium Advanced Fast Reactor (SAFR) (Baumeister, 1987), were developed primarily by General Electric (GE) and Rockwell International (RI), respectively. Technical support was provid… more

Date: October 1, 1989

Creator: Van Tuyle, G. J.; Slovik, G. C.; Chan, B. C.; Kennett, R. J.; Cheng, H. S. & Kroeger, P. G.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Xenon changes under power-burst conditions. [BWR]

Under ordinary operating conditions the xenon concentration in a reactor core can change significantly in times on the order of hours. Core transients of safety significance are much more rapid and hence calculations are done with xenon concentration held constant. However, in certain transients (such as reactivity initiated accidents) there is a very large power surge and the question arises as to whether under these circumstances the xenon concentration could change. This would be particularl… more

Date: January 1, 1983

Creator: Diamond, D. J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Identification of passive shutdown system parameters in a metal fueled LMR

This document discusses periodic testing of the passive shutdown system in a metal fueled liquid metal reactor which has been proposed as a Technical Specification requirement. In the approach to testing considered in this paper, perturbation experiments performed at normal operation are used to predict an envelope that bounds reactor response to flowrate, inlet temperature and external reactivity forcing functions. When the envelope for specific upsets lies within safety limits, one concludes … more

Date: January 1, 1992

Creator: Vilim, R.B.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Analysis of reactivity-insertion accidents in the TREAT Upgrade reactor

The expansion of the experimental capabilities of the TREAT Upgrade (TU) reactor also tends to increase the potential risks associated with off-normal reactivity insertion incidents compared to the TREAT reactor. To provide adequate prtection for the public and the facility, while meeting experimenter's requirements, a specialized Reactor Trip System (RTS) with energy-dependent scram trips on reactor power and period has been developed. With this protection strategy, the consequences of reactiv… more

Date: January 1, 1983

Creator: Rudolph, R.R. & Bhattacharyya, S.K.

Item Type: Article

Partner: UNT Libraries Government Documents Department