Guidance for Meeting Package Torque Requirements
This guidance applies only to DOE elements or persons working under contract to DOE elements
DOE elements means programs, operations offices, field/site offices, and other organizational units of the Department of Energy, excluding those of the National Nuclear Security Administration. The list of DOE elements is
here.
(link to DOE Directives website).
For Type B or fissile radioactive material packages, torque requirements are specified in its Safety Analysis Report for Packaging (SARP). Compliance with these requirements is important to the safety performance of the package under normal conditions of transport and hypothetical accident conditions with respect to the containment, shielding, and nuclear criticality safety features of the package. Proper assembly and closure of the package is a condition of use per its Certificate of Compliance (CoC). Improper assembly and closure of the package is a reportable violation per DOE Order 460.1D "... or any instances where the conditions of approval in the CoC were not met in making a shipment."
Torque wrenches used for package operations are required to be controlled under the user's M&TE (Measurement and Test Equipment) program per 10 CFR 71.125, “Control of Measuring and Test Equipment”, which "assures that tools, gauges, instruments, and other measuring and testing devices used in activities affecting quality are properly controlled, calibrated, and adjusted at specified times to maintain accuracy within necessary limits."
This guidance briefly addresses some key points regarding proper torquing of nuts, bolts, and threaded closures on Type B or fissile radioactive material packages certified by DOE (or NRC). The scope of this guidance is for package users and those who develop package operation procedures.
Guidance
This guidance is intended to provide users with reasonable assurance that proper torque is applied to nuts, bolts, and threaded closures during package operations, using a calibrated, properly qualified torque wrench.
While the type of torque wrench (click, digital, beam, etc.) may not be essential for torquing package assembly and closure bolts, the percentage (%) variance in torque wrench output is essential whether that wrench can be used for the intended application. For example, if a bolt requires 100 +/- 5 ft-lb of torque, the midpoint value of 100 ft-lb and the % variance of the torque wrench output must be within 95 - 105 ft lb. A calibrated torque wrench with 4% variance (accuracy) would be capable of ensuring torque value of 96 - 104 ft-lb. and therefore acceptable for intended application. However, the same torque wrench would not be capable of ensuring proper torque if the bolt required 100 +/- 2.5 ft-lb, since that bolt would require a torque wrench with a 2% variance to ensure a torque value of 98 - 102 ft-lb.
Factors that affect compliance with torque requirements include:
- Acceptable torque tolerance per the SARP (typically in SARP Chapter 7 Package Operations, or Drawings)
- Percentage (%) variance (accuracy) in torque wrench output
- Proper maintenance and handling of torque wrenches
- Proper practices for calibrating and verifying torque wrenches
Use of a torque tester to confirm the accuracy of a torque wrench, prior to and after its use, is recommended by DOE PCP, particularly when planning to perform "batch" closure operations on multiple packages or packages with numerous closure bolts. For example, the Model 9975 drum lid is secured with 24 bolts which are torqued to 30 +/- 5 ft-lb. DOE PCP would recommend testing the torque wrench prior to and after closure of each 9975 drum.
Torque wrenches should be handled and stored properly to protect them from impact and environmental conditions that may affect its calibration.
Additional information is available here (link to slides from NP 608 - Radioactive Material Package Operation and Leak Testing) or here (link to 2011 ASME BPVC paper from SRNL).
Drafted July 13, 2026