Maintaining High Pressure System of the HRR at Temperature After Dump

Technical Report · Tue Jul 10 04:00:00 EDT 1956

DOI:https://doi.org/10.2172/4346930· OSTI ID:4346930

Michelson, C. ^[1]

---

1. Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)

It has been suggested by kasten and others that the HRR be shut down by partially dumping the fuel solution and allowing the remaining fission product decay heat to keep the high pressure system at temperature during shutdown. An investigation of the technical feasibility of this suggestion is the subject of this report. The results of this preliminary study indicate that such an idea is feasible if the high pressure system is kept at an equilibrium temperature in the range 350-390°F during shutdown. A fuel solution holdup of 9,600-11,900 liters (7.7-9.5 kg) is required. A minimum of 9.5 Kg will make the reactor go critical at 390°F; about 8.7 Kg at 350°F. Most of the fuel solution will be in the return pipes to the reactor. The possibility of an incident which will transfer fuel to the reactor and establish a new critical geometry with a smaller fluid and fissionable material inventory is extremely remote. A detailed nuclear study is required, however, to select the safest equilibrium temperature. For initial design of the HRR, an equilibrium temperature of 190°C (374°F) is selected. A fuel holdup of about 11,000 liters (8.8 Kg) is required (critical mass, 9.3 Kg). The maximum heat demand on the system two days after shutdown is about 240 Kw; 207 Kw direct heat losses and 33 Kw evaporation requirements for gas dilution. A D₂O make up of 6800 liters is required during a two day shutdown to maintain constant fuel concentration. With a gas dilution to 5 mole percent D₂, and subsequent venting, there should be no explosion hazard. Removal of heat in excess of the requirements for venting and heat losses can be accomplished by controlled boiling at a lower pressure in one or more of the heat exchangers.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA), Nuclear Criticality Safety Program (NCSP); US Atomic Energy Commission (AEC)
• DOE Contract Number: W-7405-ENG-26
• NSA Number: NSA-11-009801
• OSTI ID: 4346930
• Report Number(s): CF-56-7-38
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
42 ENGINEERING
Analysis
BOILING
Boiling
CRITICALITY
Criticality
DAMPING
DECAY
EVAPORATION
EXPLOSIONS
Evaportation
Explosion
FISSION PRODUCTS
FUEL SOLUTIONS
Fission
Fission Product
Fuel Solutions
HEAT EXCHANGERS
HEAT TRANSFER
HEAVY WATER MODERATOR
HIGH TEMPERATURE
HOMOGENEOUS REACTORS
HRR
Hazard
Heat
Heat Exchange
LOSSES
Nuclear Criticality Safety Program (NCSP)
PIPES
PLANNING
PRESSURE
REACTOR SAFETY
RESEARCH REACTORS
Risk
SHUTDOWN
STORAGE