The document describes a robotic inspection rover called CENCIR that is designed to inspect the interior surfaces of dry storage canisters for nuclear waste. Over 1500 canisters in the US require periodic inspection to check for defects, but inspecting them presents several technical challenges due to the narrow, enclosed spaces within the canisters. CENCIR uses a modular design with vacuum-gripping pads that allow it to maneuver inside canisters, scale surfaces, and move between inner and outer surfaces to effectively inspect for cracks, corrosion or leaks while avoiding obstacles. The goal is to remotely deliver non-destructive evaluation sensors into canisters to inspect their integrity in a safe, radiologically protected manner.

1. Confined Entry Nuclear Canister Inspection Rover
(CENCIR)
Researcher: Qingtian Chen & Jonathan Liu Mentor: Professor Jizhong Xiao
Robotics Lab, City College of New York
Application Scenarios
- Over 1500 welded stainless steel dry storage canisters loaded
with spent fuel in the U.S. and approximately 200 additional
canisters being loaded each year
- Canisters provide the primary confinement barrier to prevent release
of radionuclides into the environment
- Chloride Induced Stress Corrosion Cracking of stainless steels
is possible
Specific Features
The climbing robot employs vacuum pads with a non-perfect vacuum
seal. This design allows for:
1) a higher degree of flexibility for curve and uneven surfaces
2) handling both convex and concave surfaces
3) operation in all orientations
4) tolerating small leaks
5) passing over small obstacles, such as welds, protruding bolts, and the
edges of internal cask cladding
This gives the rover greater maneuverability compared to both magnet-
ic and suction cup style climbing systems.
Technical Challenges
The surface of the canisters needs to be inspected for defects such as
stress corrosion cracking, corrosion pitting, and leakage of internal
helium. Major challenges of the robotic delivery system include:
1) traversing the narrow and tortuous vents
2) scaling vertical surfaces and traversing gaps
3)movingaroundobstacles(e.g.supportbeams,corners,bolts,&welds)
4) moving from inner to outer surfaces
5) inspecting the container surface inside narrows gaps (2.5˝ - 4˝)
6) radiation shielding, high temperature (50-80 °C), dusty surfaces
Conceptual Design
CENCIR provides a remotely operated system that is capable of de-
livering a NDE package which can effectively inspect the canister sur-
face. Our design consists of two vacuum chassis connected by a motor
controlled hinge. This allows it to move around corners, span gaps, or
transition between inner and outer surfaces. The robot folds in order to
get through tight sections of the vent or tortuous pathways. A flexible
power/communications cable allows for the rover to be safely deployed
and operated from a distance which eliminates the exposure of opera-
tors to radiation.
Project Goal
This project aims to design and test a robotic delivery system for on-
site in-situ non-destructive evaluation (NDE) of dry storage casks
used to store spent nuclear fuel. These dry storage casks consist of in-
ternal stainless steel canister covered by the concrete over-pack, and
require periodic inspection of the canister integrity in order to ensure
safe and long term storage. The Confined Entry Nuclear Canister In-
spection Rover (CENCIR) is designed to traverse through tight spaces
inside storage casks in order to inspect the canister surface in hazard-
ous and radioactive environment.
System Overview
Figure 1. Horizontal (top) and Vertical (bottom) Storage Canister
Figure 2. Vertical Storage Canister CAD models
Figure 3. Cutaway view of horizontal canister showing potential entry and exit
pathways
Figure 4. Inspection and Robotic Delivery System
Figure 5. Conceptual Design using multiple on-board vacuum
Figure 7. Single Module Prototype Figure 8. Double Module Prototype
Figure 6. Current CAD Model