MTA-EN-004 - Revision history

Colton Smith: Revision 0 Reviewed by Monica Hurley

2026-03-16T16:35:03Z

Revision 0 Reviewed by Monica Hurley

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 {{DISPLAYTITLE:Increase Control Element Drive Mechanism (CEDM) Lifespan and Reliability Through High-Temperature CEDM Gripper Coil - MTA-EN-004}}
 {{MTATemplate||
 | Date |04/23/21
@@ Line 7: / Line 8: @@
 Operations
 | Reference Implementation Guidance | 2018 NEI TIP Awards – Submittal 12 (ID: 11254843): Control Element Drive Mechanism High Temperature Coil Design
-| Industry SME | EPRI – Andrew Mantey
+| Industry SME | EPRI PRR
 Contact: NuclearPlantMod@epri.com
 | Previous Implementation | Please contact EPRI for implementation examples and contacts.
 | Implementation Enablers | N/A
 | Applicability | Combustion Engineering (CE) reactors
 All geographic regions
@@ Line 52: / Line 45: @@
 * HT‑CEDM gripper coils are electrically equivalent to the original CEDM coils. Electrical compatibility of the HT‑CEDM coils with the CEDM system should be verified prior to installation to account for any changes or modifications that have been made to the CEDM system.
 * Rotation of the reactor head is required to install all coils. To reduce the impact of coil installations on the outage schedule, it may be beneficial to install coils in sectors over multiple outages to avoid multiple reactor head rotations during the same outage.

Jacob Sommer: 1 revision imported

2026-03-05T01:37:53Z

1 revision imported

← Older revision	Revision as of 01:37, 5 March 2026
(No difference)

10.142.236.18 at 23:11, 20 February 2026

2026-02-20T23:11:28Z

New page

{{DISPLAYTITLE:Increase Control Element Drive Mechanism (CEDM) Lifespan and Reliability Through High-Temperature CEDM Gripper Coil - MTA-EN-004}}
{{MTATemplate||
| Date |04/23/21
| Functional Area Where Benefits Will Be Realized | Engineering
Maintenance

Operations
| Reference Implementation Guidance | 2018 NEI TIP Awards – Submittal 12 (ID: 11254843): Control Element Drive Mechanism High Temperature Coil Design
| Industry SME | EPRI – Andrew Mantey
Contact: NuclearPlantMod@epri.com
| Previous Implementation | Please contact EPRI for implementation examples and contacts.
| Implementation Enablers | N/A
| SWEEP Score |
* Cost – Level 2 – Cost for installation HT-CEDM gripper coils is between $1 million and $2 million.
* Savings – Level 1 – Savings from HT-CEDM coils are less than $1 million per year. Additional savings can be realized if forced outages due to coil failures are avoided.
* Payback – Level 1 – Payback period is longer than 5 years if savings are based on reduced coil replacement costs alone. Costs are recovered immediately if a coil‑related unit trip is avoided.
* Technical Readiness – Level 3 – HT‑CEDM coils are in use at US nuclear plants.
* Licensing Readiness – Level 3 – HT‑CEDM gripper coils require a design equivalency evaluation and a 50.59 screening/evaluation but no regulatory changes.
* Implementation Proficiency – Level 3 – No specific digital engineering experience is required for this technology.
*
| Applicability | Combustion Engineering (CE) reactors
All geographic regions
| Keywords | CRDM; control rod; drive mechanism; gripper; coil; combustion engineering
| Business Case Analysis Cross-Reference | N/A
}}

==Description==
Control Element Drive Mechanism (CEDM) gripper coils in Combustion Engineering (CE) plants are designed for a service life of 30 years. At the end of the service life, the coils are at elevated risk of short‑circuits between coil windings due to degradation of the winding insulation. The risk of insulation failure is increased further if the coils have been operated near or above the rated operating temperature. If a sufficient number of windings are short‑circuited, the coil is unable to perform its function, typically requiring a forced outage to replace the coil.

A US nuclear plant partnered with a vendor to develop a new gripper coil that is equivalent to the original CE coil in form, fit, and function. The new high‑temperature CEDM (HT‑CEDM) coil design features improved winding insulation to increase the temperature rating and service life of the coil to 500 °F for 60 years. The improved coil design increases coil reliability by eliminating failure modes of the original coil design (e.g., winding short circuits due to insulation limitations), which reduces the risk of coil‑related unit trips. Installation of the coils is simplified by shipping the coils as a potted assembly, instead of potting the coils at the plant during replacement.

==Benefits==
===Benefits Estimate===
Level 1 – The savings from longer coil service life and associated reduction in installation cost are less than $1 million per year. Additional savings >$5 million are realized if coil failures and associated forced outages are avoided due to improved coil design.

===Benefits Description===
* Extended coil service life of 60 years compared to 30 years for the original coils may allow plants to save a future equipment replacement cycle.
* Improved reliability of HT‑CEDM gripper coils increases nuclear safety, and reduces or eliminates outages caused by failing CEDM coils of original design.
* Reduction in installation time of HT‑CEDM gripper coils compared to the CE CEDM coils frees up resources and schedule during outage.

==Costs and Schedule==
===Cost===
Level 2 – The cost of installing HT‑CEDM coils is between $1 million and $2 million.

===Schedule===
Approximately one year.

===Scope Context===
Per unit

==Risks==
* HT‑CEDM gripper coils are electrically equivalent to the original CEDM coils. Electrical compatibility of the HT‑CEDM coils with the CEDM system should be verified prior to installation to account for any changes or modifications that have been made to the CEDM system.
* Rotation of the reactor head is required to install all coils. To reduce the impact of coil installations on the outage schedule, it may be beneficial to install coils in sectors over multiple outages to avoid multiple reactor head rotations during the same outage.