currently Hailing from Houston Texas, Bryan King is a Mechanical Engineer and Machine Designer. Contact him at supertuber@gmail.com

North Anna NGS Project

North Anna NGS Project

The job was to perform a weld overlay repair on the entry nozzle of a steam generator, a large tapered nozzle approximately 42" in diameter. My role was to design the nozzle coupon, the portion of the mock-up holding the coupon, the grinding head used to smooth the weld overlay for inspection, the track mounted to the pipe on which the weld and grinding heads ran, and to process the laser scan data from the field. The laser scan data was converted into a surface model and compared to a nominal model created from the plant's construction drawings. Supplemented by field measurements, this ensured that the mock-up clearances accurately represent the field conditions. The work was ultimately completed on time and the repair was a success. The power plant is currently providing power to the northern Virginia area.

 The mock-up coupon (clean metal portion) and the stand.  The coupon was constructed from 4" thick plates cut into 1/8 radial segments that were stacked and welded together to form the correct profile. The steel used in the coupon is sourced from the same mills that fabricated that actual nozzle material in the field. After the weld overlay is applied, sections are removed and tested to demonstrate efficacy of the weld procedure to be followed. 

The mock-up coupon (clean metal portion) and the stand.  The coupon was constructed from 4" thick plates cut into 1/8 radial segments that were stacked and welded together to form the correct profile. The steel used in the coupon is sourced from the same mills that fabricated that actual nozzle material in the field. After the weld overlay is applied, sections are removed and tested to demonstrate efficacy of the weld procedure to be followed. 

 A screenshot cross-section of the mock-up. The mockup provides a full scale environment for training and proving the process to the customer before proceeding to the field.

A screenshot cross-section of the mock-up. The mockup provides a full scale environment for training and proving the process to the customer before proceeding to the field.

 A screen shot of the grinding head. The drive assembly to the right, then the cross-feed assembly,then the grinding head itself. The grinding head is used to smooth the surface of the weld overlay so that an ultrasonic inspection can be performed. 

A screen shot of the grinding head. The drive assembly to the right, then the cross-feed assembly,then the grinding head itself. The grinding head is used to smooth the surface of the weld overlay so that an ultrasonic inspection can be performed. 

 The grinder head and cross-feed axis.

The grinder head and cross-feed axis.

 A nice feature for quick adjustment of the angle of the grind head. No play and quickly adjusted with an allen wrench. Time matters when inside containment, rad dose is kept to a minimum and workers are only allowed so much dose per year.

A nice feature for quick adjustment of the angle of the grind head. No play and quickly adjusted with an allen wrench. Time matters when inside containment, rad dose is kept to a minimum and workers are only allowed so much dose per year.

 A set of bases for laser scanning. The bases allow the scanner to be mounted as needed to accurately measure the field conditions and later confirm the clearances represented in the mockup. Left to Right: 1) tilt adapter to level the scanner, for use with the three bases to its right 2) A magnetic base 3) a plain-old set it on the ground base 4) a chain mount, where a chain is strapped around a pipe, post, or column. 

A set of bases for laser scanning. The bases allow the scanner to be mounted as needed to accurately measure the field conditions and later confirm the clearances represented in the mockup. Left to Right: 1) tilt adapter to level the scanner, for use with the three bases to its right 2) A magnetic base 3) a plain-old set it on the ground base 4) a chain mount, where a chain is strapped around a pipe, post, or column. 

 A view of the base of the track mounted to the pipe. 

A view of the base of the track mounted to the pipe. 

 Another view of the suspended portion of the track. The drive trolleys used a standard roller chain sprocket to drive the heads around the track. 

Another view of the suspended portion of the track. The drive trolleys used a standard roller chain sprocket to drive the heads around the track. 

 The track and the drive trolley partially visible

The track and the drive trolley partially visible

Angra NGS Reactor Head Replacement

Angra NGS Reactor Head Replacement

Fastpack 200

Fastpack 200