Visual and Profilometric Fuel Rod Inspection

GENERAL INFO ABOUT PROJECT

Problem Definition
Current inspection of nuclear fuel cells requires the use of cumbersome hot cells. INL is investigating an alternative process for inspecting these fuel cells that can be located closer reactor sites and does not require a dedicated building for operation. Our task is to develop segments of this process that will perform non-destructive profilometric and visual inspection of irradiated test specimens. The processes must be fast and easily serviceable while maintaining a high level of fidelity and flexibility.

Background
Inspection of nuclear fuel rods via current methods is quite cumbersome. Irradiated materials must be transported to an examination facility such as INL's HFEF. There, the fuel is inspected inside hot cells, large led lined rooms with argon atmospheres were technicians must use robot arms to interact with the material. It is difficult to implement new inspection solutions within this testing environment due to the long testing time. It is expensive to test and to improve testing methods. INL is devising a new instrument for inspecting materials known as the Modular Examination Instrument for Transportable Nuclear Energy Research (MEITNER). This device is a modular stack of examination equipment that can simultaneously inspect materials via non destructive, non contact measurements.

Deliverables
Our mission in this project is to develop the modular test cells that perform the functions of profilometry and visual inspection. These cells must be capable of taking accurate measurements under the stress of radiation. The cells must be easy to service and operate remotely.

Project Learning
''Most of the project learning for the integrated rocket ramjet revolved around ramjets and their functionality, as well as solid rockets and how to design them. For this design, in order to get the ramjet to speed a solid rocket will be attached to the ramjet engine. Once the propellant is burned, the rocket will function as the combustion chamber for the ramjet. To make this design possible, research had to be done on both rocket propellants and ramjet engines. ''

''The image on the left below shows different grain geometries for solid rocket propellant. This was useful because it helped us decide which geometry would give us the best thrust pattern to obtain the proper transition speed. We ultimately decided to go with #2, this option provided the rocket with consistent thrust which allows for easier calculations and design.''

''Along with propellant research we found information on the functionality of the ramjet. Below on the right is a basic image on how a ramjet operates. Using this information we were able to brainstorm ideas on how to create a moving nosecone and where to store the liquid fuel for the ramjet part of flight. We found the best place to store the liquid fuel would be in the extra space by the diffuser (the yellow section of the image).''

Concept and Design
''To get the Ramjet to its ideal flight path, solid rocket propellant is stored in the ramjet’s combustion chamber and functions initially as a rocket booster. During this stage the nose cone to the ramjet engine will remain shut and a diaphragm will be in place to block any solid propellant from getting into the rest of the engine (this can be seen in the first image below). ''

''Once the solid propellant is burnt, the nose cone and diaphragm open up allowing the ramjet to begin operation. This part of the design is important because it allows for the whole body to become the ramjet, and does not require the rocket portion to drop off. Instead the space where the solid rocket propellant was stored is now the combustion chamber for the ramjet. The ramjet then takes over for the rest of the flight, operating at its design conditions (this can be seen in the second image below).''

Nosecone Design
''In order to open and close the nosecone between rocket and ramjet flight, a screw mechanism has been developed to close the gap. This system uses a screw and a motor to push the front of the nosecone against the cowling to create an air tight seal, ideal for the rocket portion of flight. Once the rocket stage is complete the screw will spin within the motor pulling the front section of the nosecone back along guides. Now the inlet will be ideal for the ramjet section of flight.''

Diaphragm Design
''The second crucial component to the integrated rocket ramjet is the opening diaphragm which will take place during the transition to ramjet operations. The diaphragm consists of three bars to support a hinge, three bars to support the ends of the flaps, and the flaps that will open and close themselves. The flaps will remain closed due to the physical pressure of the solid fuel as well as the pressure created when the propellant is burning. Once the solid fuel is completely burnt the air from the moving nosecone will force the flaps open. This transforms the area where the solid rocket fuel was into a combustion chamber.''

Machining the Final Product
''To properly show the functionality and ingenuity of our design, we have developed a working 3D computer model and a quarter cutout machined model of the integrated rocket ramjet. Below images can be seen of each of the main components as they are being machined and their final product. ''

Full Assembly and Display
''Here the total Rocket Model can be seen. This assembly includes a quarter cutout view in order to show individual components, and highlights both the barrier and adjustable nose cone designs. Below the rocket can be seen at a booth display accompanied by a poster to explain project details. ''

Document Archive
[[Media: .pdf|All Meeting Minutes]]