Cosmic Ray Radiography of the Damaged Cores of the Fukushima Reactors

TL;DR

This paper compares two cosmic-ray muon imaging techniques—flux attenuation and multiple Coulomb scattering—for diagnosing damaged Fukushima reactor cores, finding scattering provides more detailed information.

Contribution

It evaluates and compares the effectiveness of muon flux attenuation and scattering methods for imaging reactor cores, highlighting the superior detail from scattering.

Findings

Scattering method offers detailed core imaging.

Attenuation method has low contrast and sensitivity.

Scattering is more effective for damaged core diagnostics.

Abstract

The passage of muons through matter is dominated by the Coulomb interaction with electrons and nuclei. The interaction with the electrons leads to continuous energy loss and stopping of the muons. The interaction with nuclei leads to angle diffusion. Two muon imaging methods that use flux attenuation and multiple Coulomb scattering of cosmic-ray muons are being studied as tools for diagnosing the damaged cores of the Fukushima reactors. Here we compare these two methods. We conclude that the scattering method can provide detailed information about the core. Attenuation has low contrast and little sensitivity to the core.