Experience with Soluble Neutron Poisons for Criticality Control at ICPP
- Idaho National Engineering Laboratory (INEL), Idaho Falls, ID (United States)
Soluble neutron poisons assure criticality control in two of the headend fuel reprocessing systems at the Idaho Chemical Processing Plant. Soluble poisons have been used successfully since 1964 and will be employed in the projected new headend processes. The use of soluble poisons (1) greatly increases the process output (2) allows versatility in the size of fuel assemblies processed and (3) allows the practical reprocessing of some fuels. The safety limit for all fluids entering the U-Zr alloy dissolver is 3.6 g/liter boron. To allow for possible deviations in the measurement systems and drift between analytical sampling periods, the standard practice is to use 3.85 g/liter boron as the lower limit. This dissolver has had 4000 successful hours of operation using soluble poisons. The electrolytic dissolution process depends on soluble gadolinium for criticality safety. This system is used to process high enriched uranium clad in stainless steel. Electrolytic dissolution takes advantage of the anodic corrosion that occurs when a large electrical current is passed through the fuel elements in a corrosive environment. Three control methods are used on each headend system. First, the poison is mixed according to standard operating procedures and the measurements are affirmed by the operator's supervisor. Second, the poisoned solution is stirred, sampled, analyzed, and the analysis reported while still in the mix tank. Finally, a Nuclear Poison Detection System (NPDS) must show an acceptable poison concentration before the solution can be transferred. The major disadvantage of using soluble poisons is the need for very sophisticated control systems and procedures, which require extensive checkout. The need for a poisoned primary heating and cooling system means a secondary system is needed as well. Experience has shown, however, that production enhancement more than makes up for the problems.
- Research Organization:
- Idaho National Laboratory (INL), Idaho Falls, ID (United States)
- Sponsoring Organization:
- USDOE National Nuclear Security Administration (NNSA), Nuclear Criticality Safety Program (NCSP)
- DOE Contract Number:
- EY-76-C-07-1570
- OSTI ID:
- 6566240
- Report Number(s):
- CONF-781105-10; TRN: 79-004575
- Resource Relation:
- Conference: ANS Meeting , Washington, DC (United States), 12 Nov 1978
- Country of Publication:
- United States
- Language:
- English
Similar Records
Second electrolytic dissolution campaign of EBR-II fuel at ICPP
CHEMICAL PROCESSING TECHNOLOGY QUARTERLY PROGRESS REPORT, OCTOBER-DECEMBER 1962
Related Subjects
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
CRITICALITY
CONTROL
DISSOLVERS
IDAHO CHEMICAL PROCESSING PLANT
SOLUBLE POISONS
BORON
GADOLINIUM
HEAD END PROCESSES
REPROCESSING
SPENT FUELS
ELEMENTS
ENERGY SOURCES
FUEL REPROCESSING PLANTS
FUELS
METALS
NATIONAL ORGANIZATIONS
NUCLEAR FACILITIES
NUCLEAR FUELS
NUCLEAR POISONS
RARE EARTHS
REACTOR MATERIALS
SEMIMETALS
SEPARATION PROCESSES
US AEC
US DOE
US ERDA
US ORGANIZATIONS
Nuclear Criticality Safety Program (NCSP)
Headend Fuel reprocessing Systems
Soluble Poisons
050800* - Nuclear Fuels- Spent Fuels Reprocessing