Shielding concerns at a spallation source

Conference · Sun Jan 01 04:00:00 EST 1989

OSTI ID:6311646

Russell, G J; Robinson, H; Legate, G L; Woods, R

Neutrons produced by 800-MeV proton reactions at the Los Alamos Neutron Scattering Center spallation neutron source cause a variety of challenging shielding problems. We identify several characteristics distinctly different from reactor shielding and compute the dose attenuation through an infinite slab/shield composed of iron (100 cm) and borated polyethylene (15 cm). Our calculations show that (for an incident spallation spectrum characteristic of neutrons leaking from a tungsten target at 90/degree/) the dose through the shield is a complex mixture of neutrons and gamma rays. High-energy (> 20 MeV) neutron production from the target is approx. =5% of the total, yet causes approx. =68% of the dose at the shield surface. Primary low-energy (< 20 MeV) neutrons from the target contribute negligibly (approx. =0.5%) to the dose at the shield surface yet cause gamma rays, which contribute approx. =31% to the total dose at the shield surface. Low-energy neutrons from spallation reactions behave similarly to neutrons with a fission spectrum distribution. 6 refs., 8 figs., 1 tab.

• Research Organization: Los Alamos National Lab., NM (USA)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 6311646
• Report Number(s): LA-UR-89-765; CONF-8810182-23; ON: DE89009406
• Country of Publication: United States
• Language: English

Related Subjects

654003* -- Radiation &amp; Shielding Physics-- Neutron Interactions with Matter
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ALLOYS
DOSE RATES
ELECTROMAGNETIC RADIATION
GAMMA RADIATION
HIGH ALLOY STEELS
IONIZING RADIATIONS
IRON ALLOYS
IRON BASE ALLOYS
NEUTRON SOURCES
NEUTRON SPECTRA
PARTICLE SOURCES
RADIATION SOURCES
RADIATIONS
SHIELDING
SPECTRA
STAINLESS STEELS
STEELS