Shielded Glove Boxes with Radioactive Sample Transfer System

In 2020-2021, Sosny R&D Company developed two facilities, each comprised of a shielded glove box with a radioactive sample transfer system and a Carl Zeiss Sigma 300 field-emission scanning electron microscope with an integrated EDS system for microanalysis. This equipment is designed for the safe preparation and micrographic examination of the radioactive samples of mixed uranium-plutonium nitride (MUPN) fuel and the homogeneity qualification of products in the analytical laboratory of the Fabrication/Refabrication Plant at the Experimental and Demonstration Power Facility (EDPF FRP). The equipment meets the radiation safety standards defined in SanPiN 2.6.1.2523–09 (NRB-99/2009) and the sanitary regulations defined in SP 2.6.1.2612-10 (OSPORB-99/2010) for Class 1 activities with unsealed sources of ionizing radiation.

Each facility includes:

  • a Carl Zeiss Sigma 300 field-emission scanning electron microscope with an integrated EDS system for microanalysis,
  • a shielded ventilated glove box enabling fully automated transfer of the samples from the shielded containers to the specimen chamber of the microscope and vice versa,
  • a local control system,
  • a radiation monitoring system,
  • a distribution cabinet,
  • ducts to arrange the cable lines at the desired height in the space between the glove box and the room wall.

The facility also includes the following transport and handling equipment:

  • a Type 1 shielded container to protect the personnel from ionizing radiation when transferring the samples to/from the glove box,
  • a Type 2 shielded container to protect the personnel from ionizing radiation when transferring fissile-containing plastic bags or spent filter of the glove box exhaust ventilation,
  • a container for collection and temporary storage of the spent plastic bags arising in operation,
  • a transport trolley for manual transportation of Type 1 and Type 2 containers.

 

The equipment components (external shielding is not shown)

 

The Carl Zeiss Sigma 300 field-emission scanning electron microscope enables backscattered electron imaging along with elementary analysis. The electron gun has an accelerating voltage range of 20 - 30000 V. The microanalysis system is based on the nitrogen-free energy-dispersive spectrometer with Мn Ка resolution up to 127 eV and the wavelength-dispersive spectrometer with resolution up to 5 eV. The radiation-protected electronic systems of the microscope enable the analysis of the specimens with the activity up to 6.8×1011 Bq.

The body of the shielded glove box and external equipment are located on the base frame, which also carries two independent lifting units to raise the shielded containers to two airlocks. The radioactive contents transfer from Type 1 and Type 2 shielded containers into the glove box and vice versa occurs via two container ports without deteriorating the glove box tightness. The container lifting, coupling to the glove box, and leak test of the coupling are controlled automatically.

 

The in-box equipment includes

 

MUPN fuel specimens are located in the sample holders during transportation in the shielded container and during an examination. One sample holder contains up to four specimens. After coupling the shielded container to the glove box, the sample holders are taken out of the container using the manipulator with the grip and arranged on the sample holder platform. The grip movements are controlled with ultrasonic sensors. The sample holders are inserted/removed into/from the specimen chamber of the microscope through the airlock using the rod. The sample holders are unloaded from the shielded container, loaded into the specimen chamber and back to the shielded container in fully automatic mode.

Manual in-box operations are performed using five glove ports. The equipment can be inserted or removed into/from the glove box through a maintenance hatch.

The box protection system prevents the exposure of the personnel to the ionizing radiation emitted by the samples in the glove box and the specimen chamber. This system features a steel frame with a three-layer biological shielding attached: a 3-mm lead sheet and two 15-mm polyethylene sheets. Organic glass windows and closing lids for glove ports are provided in the design of the shielding.

 

Glove Box with Shielding

Glove Box. Rear View

 

The glove box is equipped with the input and exhaust ventilation systems with fine filters В-0,4 TU 95 2314-98. The glove box equipment includes the instruments to monitor the air negative pressure, in-box temperature, volumetric activity, and isotope composition of aerosols.

The supply of decontaminants, compressed air and water, nitrogen and argon-methane mixture required for the microscope operation is provided.  Decontaminants are removed through the drain with a detachable trap. A vacuum dust-cleaning device is used for dry decontamination of the internal surfaces and equipment of the glove box.

The sample reloading is observed remotely and recorded with video cameras.

 

Glove Box Internals. View Through the Window

Operator's Workplace

 

Specifications of the glove box

Designation to NP-016-05  3N 
Operating medium  air 
Overall dimensions of the glove box without microscope (LxWxH)   2500×2240×2900 mm
Wall thickness  minimum 4 mm 
Vacuum gauge pressure produced by the ventilation inside the box  minimum 200 Pa 
Filter efficiency  minimum 99.995 % 
In-box air temperature  maximum 30°С 
Equivalent dose rate at any point of the glove box external surface  maximum 6 µSv/h 
Equipment operating conditions
− ambient temperature 
 from 20 °С to 30 °С
− relative humidity  maximum 80 % 
Number of windows 
Number of glove ports 
Illuminance of the working area  minimum 500 lx 
Main structural material  12X18H10T steel 

 

 

A shielded container for sample transfer (Type 1) is designed to protect the personnel against ionizing radiation when transferring the samples with the activity up to 6.8×1011 Bq.

An insert for the orderly arrangement of the sample holders is placed into the container shell. A plug and a lid serve to tighten the container and protect the personnel against ionizing radiation. The lid design also enables handling the container with a hoist by attaching the grapple (included in SPTA set) to the lid "pintle".

The design of the container body provides the shielding consisting of polyethylene and lead sheets with a thickness of 3 mm. The plug has the same protective elements.

A shielded container without an insert is utilized to transfer plastic bags with fissile material and spent В-0,4 filter.

A set of container handling tools includes:

  • a basket to secure the container on the transport trolley and to couple it with the hatch of the container port,
  • a tool to open/close the container lid,
  • a grapple to lift the container by the "pintle".

 

Specifications of the shielded container:

Safety Class to NP-016−05 
Container type to NP-063−05  Б (safe equipment) 
Capacity  Three sample holders
Overall dimensions (D´H) 261x348 mm 
Weight  maximum 43.5 kg
Inner volume without an insert  maximum 3.9 L 

 

Shielded Containers and SPTA Tools

Shielded Container in the Basket on the Transport Trolley

 

 

 

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