| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of calculating a thickness of a gap generating in a hardened material on back side of an inspected plate from a count rate ratio obtained by providing a thermal neutron ray counter at the outside of the inspected plate. SOLUTION: The method includes a step of measuring a moisture content (W) of a filler injected into a form and computing a detection thickness (D<SB>S</SB>) detectable by neutron ray for an internal condition of a structure from the moisture content using a function formula, a step of obtaining a count amount (N<SB>o</SB>) of thermal neutron ray discharged outside of a test body upon irradiating with fast neutron ray under no-gap condition using the test body prepared with the same moisture content by injecting the filler into the form to generate no gap, a step of obtaining a count amount (N<SB>p</SB>) of thermal neutron ray discharged outside of the structure upon irradiating an optional site of the inspected plate of the structure with fast neutron ray by the amount same as that of the test body, a step of obtaining (N<SB>p</SB>/N<SB>o</SB>) and determining a gap ratio (T<SB>p</SB>) therefrom, and a step of determining a thickness (D<SB>v</SB>) of the gap by multiplying the gap ratio by the detection thickness. COPYRIGHT: (C)2011,JPO&INPIT |
