Dynamic Analysis of the Chernobyl Accident
On April 26, 1986, the worst accident in the nuclear industry occurred at the Chernobyl Unit 4 reactor in the USSR. Initially, many causes were postulated for the accident; ultimately, a reactivity transient was identified as the driver for the power buildup leading to the core disruptive event. After the accident, the Hanford N-Reactor was put under close scrutiny to ascertain that a Chernobyl-type reactivity transient was not possible. Since UNC Nuclear Industries had specialized expertise in the analysis of graphite-moderated reactors, the company was requested to help identify the possible contributing factors leading to the Chernobyl transient. The support effort was in three areas: development of a three-dimensional model of the Russian reactor to establish flux and power distributions, lattice cell calculations to compute reactivity coefficients and to generate cross sections for static and dynamic analyses, and performance of dynamic calculations exploring the contribution of control rod action on the reactivity transient. As part of the flux-flattening program for the N-Reactor, the DELPHI code has been developed. This particular code solves the static diffusion equation for two energy groups in three dimensions. The code includes thermal-hydraulic feedback and burnup considerations. The basic code was modified, and the Chernobyl 4 reactor was modeled and evaluated. Useful information on flux distributions for subsequent analyses was obtained.
- Sponsoring Organization:
- USDOE National Nuclear Security Administration (NNSA), Nuclear Criticality Safety Program (NCSP)
- OSTI ID:
- 6941621
- Report Number(s):
- CONF-8711195-
- Journal Information:
- Transactions of the American Nuclear Society, Journal Name: Transactions of the American Nuclear Society Vol. 55; ISSN TANSA; ISSN 0003-018X
- Publisher:
- American Nuclear Society
- Country of Publication:
- United States
- Language:
- English
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