Insitu Pressure Testing
In-situ pressure testing (ISPT) allows for the hydrostatic pressure testing of installed heat exchanger / steam generator (SG) tubing in the field providing a direct means of demonstrating the structural and leakage integrity of the tube Leak test correction factors are used to adjust the test pressure to take into account temperature corrections, gauge uncertainty and simulated external loads if applicable. The results of the tests can be used in the Fitness for Service analysis to demonstrate that the performance criteria of the tube have been met.
BWXT’s ISPT equipment consists of the following components:
Multiple tool heads for sealing and pressurizing either localized sections of tubes (4”-6”) or the full length of the tube. The localized tool applies an axial load to the tube which can be important when assessing certain tube defects. It uses seals to isolate a specific tube section for testing and has an integrated vent to remove air from the test chamber. Full length tube testing involves inserting a plug-type tool into each end of the tube. This tool is also includes a means to remove air from the tube prior to testing. These tool heads are custom designed in different sizes to precisely fit the tubes being tested. Long high-pressure hoses so that the pump systems can be located away from the SG platform. This allows for the tools to be operated remotely and therefore reduces the radiation exposure of the operators.
A closed loop controller for controlling, monitoring and maintaining the test pressure. Pressures and flow rates are displayed on a built-in touch screen. The user-friendly controller has an integral data logger that digitally stores the test pressures and flow rates with respect to time. Data from the testing can be easily downloaded for analysis of the overall test results.
The ISPT equipment is qualified in accordance with the requirements of Section 10 of the EPRI Steam Generator In-Situ Pressure Testing Guidelines 1014983 Revision 3. These guidelines are the industry standard for ISPT.
The ISPT qualification includes:
- The maximum test pressure capability of the system
- The maximum and minimum measurable flow rates
- Test results demonstrating equipment applies the appropriate axial and hoop stress to the tubes
- The accuracy with which the localized tool can be positioned
- The maximum temperature at which the ISPT equipment is qualified
- The minimum number of cycles for which the seals may be used
- The system pressure drop vs. leak rate relationship such that the actual pressure at the flaw is known for leak rate correction
- An analysis quantifying the maximum residual effects on tested tubes
Key Features & Benefits:
- Capable of being delivered into the steam generator using a standard eddy current probe delivery system which allow the utilization of existing equipment and operators and minimizes dose to workers
- Capable of full length or localized tube testing, providing maximal flexibility for assessing all tube conditions.
- An integral part of BWXT’s all-in-one inspection system that can be applied to multiple SG types
- Meets EPRI guidelines for in-situ pressure testing
- Digital controlled with simple, intuitive interface minimizing operator learning curve and training requirements
- Process system skid is designed with color coded fittings and connectors for ease of set-up and optimized to facilitate decontamination if required.
- System is portable and lightweight, designed for ease of transport and set-up