Diagnostic Services

Crane Nuclear Diagnostic Testing Services

Few companies in the industry can attest to providing diagnostic testing service support for over 600 nuclear utility outages. An even fewer number can compete with the superior level of full-scope work that is performed by Crane Nuclear during these outages. For over 35 years, our full-time staff of highly skilled and experienced personnel has provided support for the development and implementation of valve engineering and maintenance programs in nearly every US nuclear power plant and several international nuclear power plants for Motor-Operated Valves (MOVs), Air-Operated Valves (AOVs), and Check Valves (CVs).

AOV Diagnostic Testing

AOV Diagnostic Testing provides information that may be used to calibrate AOV components, verify conformance with design basis, and accurately determine component hysteresis, dead band, and valve stroke length. AOV Diagnostic Testing enables the user to determine the following parameters:


Total Travel


Signal, Maximum Travel


Valve Dynamic Hysteresis Error


Valve Dynamic Linearity Error


Minimum Benchset


Spring Rate, Seat Load


Direct Stem Thrust


Signal Pressure, Minimum Travel


Positioner Dynamic Hysteresis Error


I/P Output Pressure, Minimum Signal


I/P Dynamic Hysteresis Error


Air Supply Pressure Change

MOV Diagnostic Testing

Crane Nuclear started MOV Diagnostic Testing services in the early 1980s after developing the first MOV diagnostic system, an oscilloscope-based system known as the 2100 System.

With our extensive MOV testing experience, our personnel are able to perform diagnostic testing, acquire test data, troubleshoot MOV problems and perform analysis. We ensure Static Testing Activities are in accordance with the sites’ GL 89-10 testing requirements and/or Appendix III requirements.

Test personnel will verify no electrical or mechanical degradations are present that may jeopardize continued in-service operation of the MOV. Analysis includes verification that no setpoints have been exceeded. The acquired data is used to adjust torque and limit switches to the proper setpoints for thrust and torque, bypass, stroke, and light indication times.

The following data is collected during MOV acquisition:

  • Stem Thrust
  • Actuator Output Torque
  • Spring Pack Displacement
  • Motor Current
  • Motor Power
  • Stem Position
  • Control Switch Trip
  • Stem Travel
  • Differential Pressure
  • Upstream & downstream pressures during dynamic(DP) testing
  • Limit Switch Settings
  • Motor Voltage
  • Stroke Time
  • Compensator Deflection
  • Motor Power(requires optional power module)

The acquired full-stroke signatures are retained for permanent records and future analysis, after all criteria has been satisfied. Future testing periodicity is established after the data review and acceptance.

Check Valve Testing Services

Crane has been providing comprehensive Check Valve Services to the nuclear industry since 1986. Crane Nuclear has provided successful check valve diagnostic testing services with a high level of success throughout the electric power industry. Testing expertise includes both steady state testing to satisfy INPO SOER 86-03 requirements along with full stroke testing to satisfy ASME Section XI. Crane Nuclear is highly experienced in data evaluation for both methods of acquisition.

Our experience is a result of continuous testing in our flow loop on known degradations along with our industry leading field experience acquired over more than 35 years. Crane Nuclear is providing the nuclear power industry with critical check valve testing and analysis resulting in determination of conditions detrimental to proper operation of check valves.

This information is then applied to assess corrective actions, such as repair or replacement. Having sound knowledge of the check valve condition, and the ability to predict maintenance, provides economic benefits to the customer.

EPRI Standardized Task
Evaluation (STE) Program

The EPRI STE Program employs a proven knowledge and skills evaluation process providing a means of demonstrating and documenting an individual’s competencies facilitating both in house and portable qualifications.

STEs are task-specific tests designed to validate that an individual is proficient in performance of given tasks. Each STE covers particular pieces of equipment that serve a common function (e.g., centrifugal pumps) or process (e.g. clean and inspect). STEs are designed to be used in multiple plant/site applications without further modification by the implementing plant/site. An STE consists of two parts: The examinee demonstrates knowledge requirements by completion of a written examination and then skills by discussing, simulating, and/or performing task elements.

Crane Nuclear attained EPRI STE Program: Administration Protocol for Portable Practicals (AP3) Compliancy as of September 1, 2020.

Support Transitioning to
Appendix III and IV.

As U.S. Nuclear Power Plants review their programs to align with the Mandatory Appendix III and Appendix IV programs, Crane Nuclear has been involved in assisting customers to review previous test data such as that from In-service MOV Test Programs and GL 89-10/96-05 Programs to help meet the Appendix III requirements.

We help our customers assess program scope differences, determine test frequencies for in-service and exercising, and update the IST program to reflect all changes. Our team will make the transition as smooth as possible.

Emergency Valve Parts & Machining: 800-272-6315