RSP11 – Decay in Storage

No./Title: RSP11 – Decay in Storage

Resp. Office: Research Safety Affairs

Effective Date: 1/24/2021

Category: Radiation Safety

Last Review: 1/24/2020

Next Review: 1/24/2024

Contact: Jabari Robinson, Radiation Safety Officer,

Office of Research Safety Affairs




To outline the procedure for Decay in Storage (DIS) management of radioactive wastes at UT Health Science Center.


One way in which radioactive wastes are managed is through the process known as Decay In Storage (DIS). Under this management technique, waste is segregated and stored until it is no longer radioactive. Confirmatory measurements are then made, and the waste is released into the appropriate non-radioactive waste stream.


  • Survey meter with appropriate probes.
  • PPE (gloves, lab coat, etc.)
  • Waste packaging materials
  • Hand Truck or Cart (for transport)
  • Pen, calculator and log sheets




Segregation and Packing of DIS waste.

All radioactive waste is sorted by type and isotope. Wastes of the same type and isotope are packaged together in drums. As parcels are put into the drum, the inventory of materials in that drum is updated. Each drum is assigned a unique number for tracking purposes. Full drums are currently stored in the 1st floor waste storage room in Van Vleet.

Release of DIS waste

Once the radioactive waste is no longer radioactive (as determined by calculation) it may be released to the normal waste stream. As part of this process, each parcel of waste is scanned with a survey meter (using both a GM and low energy NaI probe) to ensure that it is indistinguishable from background levels.

  • Record all survey results on the appropriate log sheets.

RSP11 – Decay in Storage
Version: 1 // Effective: 01/24/2021
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