Reduce Large Heat Exchanger Replacement Costs Using Modified Crawler Vehicle - MTA-MA-018

Administrative Items
Date	12/15/2020
Functional Area Where Benefits Will Be Realized	Maintenance
Reference Implementation Guidance	2019 NEI TIP Awards – Submittal 25 (ID: 12296074)
Industry SME	Contact: NuclearPlantMod@epri.com
Previous Implementation	Please contact EPRI for implementation examples and contacts.
Implementation Enablers	None
SWEEP Score	Cost – Level 3 – The cost per FWH is typically less than $1 million Savings – Level 2 – Savings of approximately $4 million per FWH have been reported for a limited access location Payback – Level 3 – The payback is immediate because the cost is similar to other available technologies while providing savings due to process improvements. Licensing Readiness – Level 3 – This technology does not require regulatory review. Technology Readiness – Level 3 – This technology has been used at nuclear plants. Implementation Proficiency – Level 3 – The implementation of this technology does not require knowledge of digital technologies.
Applicability	All reactor types All geographic regions
Keywords	Feedwater heater; tube bundle replacement; rigging; equipment transport; reduced outage time; crawler
Business Case Analysis Cross-Reference	N/A

Description

Large heat exchanger components, such as feedwater heater (FWH) tube bundles, are often installed in locations that make replacement difficult and expensive. A major challenge during replacement lies in transporting the old and new tube bundles out of and into the turbine building. This task may not be feasible or cost‑effective using traditional rigging and transport methods (e.g. slide rails). Remote controlled, low‑profile skid‑steer crawler vehicles have been used successfully to transport FWHs during replacement. The crawlers include an adjustable wheelbase, can move about several degrees of freedom, and are designed to transport heavy loads in industrial environments. This MTA is based on a case study of a FWH tube bundle replacement project; however, the use of crawlers for transporting large and/or heavy equipment is not restricted to this application.

Benefits

Benefits Estimate

Level 2 – Savings are between $1 million and $5 million per FWH. Savings of approximately $4 million per FWH have been reported due to shortening of the critical path of an outage.

Benefits Description

• Reduction of time, man‑hours and dose required to replace FWH tube bundles
• Reduced risk associated with lifting heavy equipment
• Minimal on‑site preparation requirements for deployment of crawlers
• Enables replacements that would be cost‑prohibitive or otherwise infeasible using traditional lifting and transport methods
• Improved load distribution on floor due to size of crawler tracks, may eliminate need for structural reinforcement of floors

Costs and Schedule

Cost

Level 3 – Cost for FWH heater tube bundle replacement using crawler is typically less than $1 million per FWH. The cost is comparable to that for traditional transport methods (e.g., slide rails). Information provided by rigging contractor.

Schedule

~18‑24 months (for work planning and procurement tasks)

Scope Context

Per FWH

Risks

• The path of the crawlers can be complex. Replacement planning should include a detailed haul path. Personnel planning should take into account the staff required to monitor the crawlers’ movement and to avoid contact of the crawlers or the load with other plant equipment and the crawlers’ hydraulic hoses.
• Crawlers are controlled wirelessly. Plants need to evaluate the risk of radio‑interference or work with the vendor/contractor to develop wired controls.
• Otherwise, no unique risks beyond standard project risks associated with implementing large equipment replacements at nuclear power plants.