Foundation fieldbus tested for nuclear plant, safety applications

When the managing director of British Nuclear Fuels' (Warrington, U.K.) BNFL Engineering division challenged its staff to cut costs by 25%, they decided to examine fieldbuses for savings and future platform growth. Tom Nobes, BNFL's senior systems engineer, says he and his colleagues were attracted to using a fieldbus by its simplified cabling; reduced installation costs; more flexible ordering...

06/01/2002


When the managing director of British Nuclear Fuels' (Warrington, U.K.) BNFL Engineering division challenged its staff to cut costs by 25%, they decided to examine fieldbuses for savings and future platform growth. Tom Nobes, BNFL's senior systems engineer, says he and his colleagues were attracted to using a fieldbus by its simplified cabling; reduced installation costs; more flexible ordering due to programmable instruments; and improved diagnostics for optimized production and targeted maintenance.

"We can keep an eye on instruments that are more critical to the process, rather than simply calibrating them all at regular intervals, whether they need it or not," says Mr. Nobes. "Anything we can do to avoid visiting instruments is an advantage."

Starting small

Mr. Nobes says BNFL began evaluating fieldbus at its small pilot plant at BNFL Springfields, near Preston, U.K. The plant uses mostly inert materials, such as water and Fullers Earth, to test filter efficiency. "We saw that rig as having virtually no safety implications, and we decided to outfit that system with fieldbus products, rather than conventional instruments. In this way, this system became a test rig for filters, as well as a fieldbus test rig."

BNFL also formed an internal committee to ensure that all divisions signed up for the same fieldbus for the same reasons. The committee eventually produced an internal standard, or code of practice, to prevent unauthorized systems from being introduced at any of its sites.

"We listed all the protocols available, and stopped when they reached 26," says Mr. Nobes. "We chose FOUNDATION fieldbus because we felt it most suited our requirements for speed, deterministic operation and time synchronization. A big advantage of FOUNDATION fieldbus to BNFL is its use of function blocks." Function blocks are uniform pieces of device description language used to carry out control functions in devices, and are standardized to ensure interoperability.

The filter test rig at BNFL Springfields was fitted with 30 loops and FOUNDATION- based products . The control systems, pressure transmitters, electromagnetic flowmeters and vortex flowmeters are from Yokogawa; level-measuring instruments are from Endress & Hauser; temperature transmitters are from Smar, and its control valves are from Flowserve.

Seeking safety

Mr. Nobes says the project's first objective is to determine if a FOUNDATION fieldbus-based basic plant control system (BPCS) has demand rates and risk reduction factors that are no worse than existing, conventional DCS-based BPCS. Its second task is to assess implications of possible future use of FOUNDATION fieldbus in safety related applications up to SIL 1, which equals 85% of all trips at BNFL.

"Before trying to use fieldbus in active plants for safety, we're seeking to prove that fieldbus is no less reliable than a conventional 4-20 mA system," says Mr. Nobes. "BNFL works under the regulatory supervision of the Nuclear Installations Inspectorate (NII). Safety is BNFL's No. 1 priority. Safety in our plant is enhanced by instrument systems with alarms and trip actions. Before we approach the NII to let them know that we want to start using FOUNDATION fieldbus in our main plants, we need to establish a track record in simpler plants. Using small plants, we can gain experience; graduate upwards from there; and, in a few years, we could look at fitting FOUNDATION as our first choice."

So far, the filter test rig has operated for 12 months without any significant failures, and Mr. Nobes says it has logged every scrap of data from its instruments. This information will be used to build the performance statistics for a mean time between failure (MTBF) argument supporting eventual use of fieldbus in larger and more critical settings. In fact, BNFL is already designing a sump monitoring system with 230 FOUNDATION fieldbus loops.

However, to serve in safety settings, FOUNDATION fieldbus-based equipment will also have to survive failure mode effect analyses (FMEA) that break devices into component parts, and proactively try to determine how they might fail.

For more information, visit www.fieldbus.org .


Author Information

Jim Montague, news editor jmontague@cahners.com


Use this 'To Do' List for Fieldbus Projects

MSet up a fieldbus awareness group or committee that includes everyone with input on the plant, such as designers, installers, users, maintainers and buyers.

Decide on an internal fieldbus standard, policy or procedure that meets the needs of the organization's application.

Test potential fieldbus candidates in small, less-critical settings that appropriately simulate the applications in which they may eventually serve.

Seek to ensure that the fieldbus selected also fits into the company's quality assurance system.

Provide enough fieldbus training to potential users.

Source: Control Engineering with information from British Nuclear Fuels



No comments
The Engineers' Choice Awards highlight some of the best new control, instrumentation and automation products as chosen by...
Each year, a panel of Control Engineering editors and industry expert judges select the System Integrator of the Year Award winners.
The Engineering Leaders Under 40 program identifies and gives recognition to young engineers who...
Learn how to increase device reliability in harsh environments and decrease unplanned system downtime.
This eGuide contains a series of articles and videos that considers theoretical and practical; immediate needs and a look into the future.
Learn how to create value with re-use; gain productivity with lean automation and connectivity, and optimize panel design and construction.
Go deep: Automation tackles offshore oil challenges; Ethernet advice; Wireless robotics; Product exclusives; Digital edition exclusives
Lost in the gray scale? How to get effective HMIs; Best practices: Integrate old and new wireless systems; Smart software, networks; Service provider certifications
Fixing PID: Part 2: Tweaking controller strategy; Machine safety networks; Salary survey and career advice; Smart I/O architecture; Product exclusives
The Ask Control Engineering blog covers all aspects of automation, including motors, drives, sensors, motion control, machine control, and embedded systems.
Look at the basics of industrial wireless technologies, wireless concepts, wireless standards, and wireless best practices with Daniel E. Capano of Diversified Technical Services Inc.
Join this ongoing discussion of machine guarding topics, including solutions assessments, regulatory compliance, gap analysis...
This is a blog from the trenches – written by engineers who are implementing and upgrading control systems every day across every industry.
IMS Research, recently acquired by IHS Inc., is a leading independent supplier of market research and consultancy to the global electronics industry.

Find and connect with the most suitable service provider for your unique application. Start searching the Global System Integrator Database Now!

Case Study Database

Case Study Database

Get more exposure for your case study by uploading it to the Control Engineering case study database, where end-users can identify relevant solutions and explore what the experts are doing to effectively implement a variety of technology and productivity related projects.

These case studies provide examples of how knowledgeable solution providers have used technology, processes and people to create effective and successful implementations in real-world situations. Case studies can be completed by filling out a simple online form where you can outline the project title, abstract, and full story in 1500 words or less; upload photos, videos and a logo.

Click here to visit the Case Study Database and upload your case study.