ANALYSIS OF RADIATION FROM HNPF COLD TRAPS AND PRIMARY SODIUM PUMPS DURING REMOVAL AND SHIPPING

Technical Report · Tue Dec 15 04:00:00 EST 1959

DOI:https://doi.org/10.2172/4702823· OSTI ID:4702823

Rhoades, W A

The expected maximum contamination of the HNPF cold traps and primary sodium pumps was determined along with the maximum dose rates from these components during removal and shipping. Suitable shielding for casks to be used in the removal operation and for shipping these components away from the reactor site is specified. Access to an unshielded cold trap is limited by high dose rates, i.e., 100 mr/hr at 120 ft, after 180 days decay time. A handling cask providing a radial shield of 3 in. of lead will provide adequate personnel protection for the removal operation, if 180 days decay time is allowed before the trap is removed. An additional 2.4 in. of lead is required for offsite shipment of the cask. This additional shielding can be added after the trap is removed from the reactor building. Dose rates from the cold trap after the shield plug is removed from the access hole are shown. If direct line-ofsight exposure is avoided, dose rates to personnel will be below 100 mr/hr at any position, and below 10 mr/hr at distances greater than 20 ft from the access hole. Dose rates from the cask during its travel away from the hole, will be below 100 mr/hr at distances from the cask greater than 10 ft and below 10 mr/hr at 35 ft, if the cask is raised no more than 3 in. from the floor during its travel. Remote, unshielded handling of a primary sodium pump is feasible, since dose rates would be 100 mr/hr at 28 ft and 10 mr/hr at 90 ft, after ten years of operation, and providing that 14 days decay time is allowed to eliminate activity from the Na/sup 24/ film clinging to the pump. Dose rates after only one year of operation would be lower by a factor of 4. The cold trap handling cask can also be used for sodium pump removal. Additional shielding of 1 in. of lead is required for off-site shipment of the pump. Dose rates from the cask during pump handling will be well below those during handling of the cold trap, and thus will present no serious difficulty. (auth)

• Research Organization: Atomics International. Div. of North American Aviation, Inc., Canoga Park, Calif.
• Sponsoring Organization: USDOE
• DOE Contract Number: AT(11-1)-GEN-8
• NSA Number: NSA-17-024634
• OSTI ID: 4702823
• Report Number(s): NAA-SR-Memo-4757
• Country of Publication: United States
• Language: English

Related Subjects

CONTAMINATION
COOLANT LOOPS
DECAY
FILMS
HNPF
LEAD
LIQUID METAL COOLANT
PERSONNEL
PUMPS
RADIATION DOSES
RADIATION PROTECTION
RADIATIONS
RADIOACTIVITY
REACTOR TECHNOLOGY
REACTORS
REMOTE HANDLING
SHIELDING
SODIUM
SODIUM 24
TRANSPORT
TRAPS