Solid-state track recorder neutron dosimetry in the Three-Mile Island Unit-2 reactor cavity
Solid-state track recorder (SSTR) neutron dosimetry has been conducted in the Three-Mile Island Unit (TMI-2) reactor cavity (i.e., the annular gap between the pressure vessel and the biological shield) for nondestructive assessment of the fuel distribution. Two axial stringers were deployed in the annular gap with 17 SSTR dosimeters located on each stringer. SSTR experimental results reveal that neutron streaming, upward from the bottom of the reactor cavity region, dominates the observed neutron intensity. These absolute thermal neutron flux observations are consistent with the presence of a significant amount of fuel debris lying at the bottom of the reactor vessel. A conservative lower bound estimated from these SSTR data implies that there are at least 2 tonnes of fuel, which is roughly 4 fuel assemblies, at the bottom of the vessel. The existence of significant neutron streaming also explains the high count rate observed with the source range monitors (SRMs) that are located in the TMI-2 reactor cavity.
- Research Organization:
- Hanford Engineering Development Lab., Richland, WA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC06-76FF02170
- OSTI ID:
- 5732080
- Report Number(s):
- HEDL-7484; ON: DE85011360
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
THREE MILE ISLAND-2 REACTOR
NEUTRON DOSIMETRY
RADIATION DETECTORS
BIOLOGICAL SHIELDS
ELECTRONIC EQUIPMENT
NONDESTRUCTIVE TESTING
PRESSURE VESSELS
REACTOR VESSELS
THERMAL ANALYSIS
CONTAINERS
DOSIMETRY
ENRICHED URANIUM REACTORS
EQUIPMENT
MATERIALS TESTING
MEASURING INSTRUMENTS
POWER REACTORS
PWR TYPE REACTORS
REACTORS
SHIELDS
TESTING
THERMAL REACTORS
WATER COOLED REACTORS
WATER MODERATED REACTORS
210200* - Power Reactors
Nonbreeding
Light-Water Moderated
Nonboiling Water Cooled