Discussion Overview
The discussion revolves around calculating the effective multiplication factor (keff) and total fission produced during a critical accident in a cylindrical model. Participants explore methods for these calculations, particularly in the context of using MCNP 5 software and specific materials.
Discussion Character
- Technical explanation
- Mathematical reasoning
- Exploratory
Main Points Raised
- One participant mentions calculating keff using MCNP 5 but expresses uncertainty about calculating total fission produced.
- Another participant suggests taking fuel depletion in atoms as a method for calculating total fission.
- A different participant proposes that total fission could be calculated as the integral of Ʃf and neutron flux over volume and time, assuming a Gaussian pulse and prompt neutron flux.
- There is a request for clarification on Ʃf, particularly in relation to thermal neutrons and fission caused by U235.
- Participants discuss the initial form of the material (solid metal, ceramic, or aqueous solution) and its impact on reactivity estimation from keff-1.
- One participant provides the formula for Ʃf as NU235 * σf, where N is the atomic density of the material.
- Another participant inquires about finding σf for a specific solution (UO2(NO3)2 . 6 H2O) and is directed to resources for cross-section data.
- It is noted that there will be no delayed neutrons in the calculations.
Areas of Agreement / Disagreement
Participants express various methods and approaches for calculating total fission and keff, but there is no consensus on a single method or resolution of uncertainties related to the calculations.
Contextual Notes
Participants mention dependencies on specific definitions and the need for clarity on certain variables, such as σf, without resolving these uncertainties.