SNM holdup assessment of Los Alamos exhaust ducts. Final report

Technical Report · Tue Feb 01 00:00:00 EST 1994

DOI:https://doi.org/10.2172/10126202· OSTI ID:10126202

Marshall, R S

Fissile material holdup in glovebox and fume hood exhaust ducting has been quantified for all Los Alamos duct systems. Gamma-based, nondestructive measurements were used to quantify holdup. The measurements were performed during three measurement campaigns. The first campaign, Phase I, provided foot-by-foot, semiquantitative measurement data on all ducting. These data were used to identify ducting that required more accurate (quantitative) measurement. Of the 280 duct systems receiving Phase I measurements, 262 indicated less than 50 g of fissile holdup and 19 indicated fissile holdup of 50 or more grams. Seven duct systems were measured in a second campaign, called Series 1, Phase II. Holdup estimates on these ducts ranged from 421 g of {sup 235}U in a duct servicing a shut-down uranium-machining facility to 39 g of {sup 239}Pu in a duct servicing an active plutonium-processing facility. Measurements performed in the second campaign proved excessively laborious, so a third campaign was initiated that used more efficient instrumentation at some sacrifice in measurement quality. Holdup estimates for the 12 duct systems measured during this third campaign ranged from 70 g of {sup 235}U in a duct servicing analytical laboratories to 1 g of {sup 235}U and 1 g of {sup 239}Pu in a duct carrying exhaust air to a remote filter building. These quantitative holdup estimates support the conclusion made at the completion of the Phase I measurements that only ducts servicing shut-down uranium operations contain about 400 g of fissile holdup. No ventilation ducts at Los Alamos contain sufficient fissile material holdup to present a criticality safety concern.

• Research Organization: Los Alamos National Lab., NM (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States); USDOE National Nuclear Security Administration (NNSA), Nuclear Criticality Safety Program (NCSP)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 10126202
• Report Number(s): LA--12700; ON: DE94007116
• Country of Publication: United States
• Language: English

Related Subjects

054000
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
CRITICALITY
DEPOSITION
DUCTS
EXHAUST SYSTEMS
EXPERIMENTAL DATA
FISSILE MATERIALS
FUME HOODS
GLOVEBOXES
HEALTH AND SAFETY
LANL
NONDESTRUCTIVE ANALYSIS
NUCLEAR FACILITIES
Nuclear Criticality Safety Program (NCSP)
PLUTONIUM 239
PROGRESS REPORT
RADIATION DETECTORS
SAFETY ANALYSIS
STATISTICS
SURFACE CONTAMINATION
URANIUM 235