Valve innovation helps with nuclear waste

Valves and actuators designed for handling radioactive waste must meet strict government requirements. This sometimes requires unconventional solutions. Such was the case at the Hanford Waste Treatment Project (WTP), Hanford, Wash.

By Roy Johnson, Flowserve

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Overcoming an engineering challenge

“This project was definitely a challenge,” says Rohrig. “We’ve done a lot of stem extensions but nothing like these. Not only did the extensions have to telescope, they also had to be designed to take the weight of the stem extension off of the valves. Bechtel also had a variety of torque requirements for these valves, from 500 to 20,000 inch-pounds.”

Bechtel liked the stem extension concept Flowserve presented. As a result, Automax pneumatic actuators with Foundation Fieldbus switches were also qualified by Bechtel after meeting additional Bechtel and DOE requirements. A contract for the bulge valves and automation valued in excess of $1 million was signed in August 2002, with Flowserve as the exclusive source for bulge valves. So far, Flowserve has worked with one of several bulge manufacturers to complete the first bulge containing 22 valves. Other bulge valve orders are in process.

The jumper valves

After the first order had been received for the bulge valves, Flowserve began receiving inquiries from Bechtel about its capabilities for the “jumper valve” portion of the project. The Flowserve team presented Bechtel with another modified Mach 1 valve featuring Automax stainless steel rack-and-pinion valve automation packages to meet the requirements of this application (Figure 4).

The specification for the jumper valves called for fully automated valves to be used within the pretreatment building with the same requirements for radioactive slurry handling as the bulge valves. Due to the intense radioactive levels inside the pretreatment building, the jumper valves were to be operated and repaired remotely by robotic devices. These valves also were specified with radiation-resistant pneumatic actuators, switches and accessories, which were to be mounted directly on the valve bodies.

Unlike the bulge valves, the jumper valves couldn’t be built with stem extensions used to pull the plug and sleeve out of the valve body for repair. The challenge was to develop a “jack nut” feature that would enable the remote release and replacement of the plug and sleeve cartridge assembly by a robot. Additional design changes were required to modify the actuators and mounting kits so that the actuation packages could be removed for access to the top of the valve for cartridge replacement.

Although Bechtel didn’t require another upfront demonstration, several design modifications were required. Space constraints forced Flowserve to propose smaller stainless steel Flowserve Worcester Controls rack-and-pinion actuator units not previously manufactured with stainless steel materials in place of the larger standard Automax stainless steel actuators originally proposed.

“The pretreatment building is a huge facility with lots and lots of equipment,” says Shaw. “Everything is installed very closely together. It became apparent that we had to build a very compact automation package. Bechtel gave us specific space dimensions that we had to meet. So we had to be flexible in what we were offering to Bechtel to meet their requirements.”

Bechtel next wanted proof that the actuators would meet NQA-1 inspection requirements and that Flowserve could guarantee Bechtel it would meet promised delivery schedules. After satisfying Bechtel’s requirements, Flowserve received another multi-million dollar order for the automated jumper valves in August 2004.

“We worked very hard to gain Bechtel’s confidence so we could design valve and automation packages that would meet the needs of their applications and facilities,” says Shields. “We came up with two plug valve designs that were unique. That’s what put us ahead of the competition.”

Roy Johnson is NW regional manager in Cookville, Tenn.; e-mail him at
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