Fossil & Nuclear
Fossil & Nuclear
Offering a Full Range of Traditional and Advanced NDT Methods
MISTRAS provides inspection services and monitoring products and software to the fossil and nuclear industries. MISTRAS services encompass the entire range of conventional and advanced NDT (Nondestructive Testing) methods, which can be delivered conventionally, or via rope-access, saving considerable access costs when compared with scaffold. Our rope access technicians can do any mechanical work necessary to access surfaces for measurement or installation of monitoring sensors, together with any restorative work. Automated robotic inspection methods provide rapid acquisition of thickness and other data by the use of computer controlled mapping and inspection systems. Systems and advanced services are provided for a wide range of specialist power industry applications, examples include:
We offer leakage monitoring for valves, boilers, HRSG's, and high integrity pipework. Permanently installed, these systems provide information on any steam leakage, and have an exceptionally high sensitivity. A leaking turbine bypass valve can cost in excess of £200,000 per annum in lost generation. Leakage from RV's and other system steam leaks can amount to sums exceeding this. MISTRAS valve leakage monitoring systems are able to estimate leakage rates. Early detection of any leakage on HEP (High Energy Pipework) is essential to avoid risk of a major rupture, and MISTRAS systems are able to detect leakage from as little as 1 gram per second on an operating main steam or hot re-heat line, providing sufficient warning to allow an orderly shutdown.
MISTRAS now has in excess of 300 "Triple 5" boiler steam leak monitoring systems in operation. These sensitive "early stage" leak detection systems allow the plant to plan ahead for any shutdown, often allowing our clients to run for many weeks nursing a known leak. Boiler leakage specialists in the MISTRAS remote monitoring service provide analysis and advice on the development of leaks 365 days per year, 24 hours per day, allowing owners to maximize uptime and minimize maintenance and operating costs.
MISTRAS PowerPAC™ testing technology was developed together with, and is endorsed by EPRI (Electric Power Research Institute), it provides information on the 3D location of sources of potential and actual problems inside operating power transformers. The most common use is on gassing transformers to locate the source, determine the conditions under which the source is active, and hence identify the likely cause. In many cases the information gathered allows a transformer to be nursed by avoiding the conditions that result in further damage, such as avoiding particular taps, or maintaining load and temperature below the threshold where damage occurs.
Stress Corrosion Cracking (SCC)
Systems to identify the development of SCC (Stress Corrosion Cracking) in stainless equipment and are installed on nuclear and process plant. Static sensors mounted in the area of interest and connected to specialist networked monitoring systems, identify the development of SCC, improving plant safety. These systems are remotely managed wherever possible by specialist MISTRAS personnel.
ACTMS for monitoring of Combined Cycle Gas Turbines
More than 45 CCGT's (Combined Cycle Gas Turbines) are currently monitored to detect the onset of stator vane cracking using MISTRAS ACTMS systems. These systems have already prevented stator vane liberation with its consequential costs running into millions, and provide cost effective insurance against this event.
CCGT Enclosure Leak Detection Systems
MISTRAS CCGT enclosure leak detection systems help clients conform to UK HSE (Health and Safety Executive) guidance note PM 84 which states that once a GT is in operation a regular scheme of inspection for air and gas leaks should be implemented. PM 84 also states that all options for carrying out the work from outside the acoustic enclosure must be considered, to minimize risk to personnel. MISTRAS systems are intrinsically safe and connect direct to the plant DCS via a 4-20ma loop and standard galvanic safety barrier.
Loose Parts Monitoring Equipment (LPME)
MISTRAS LPME systems use low frequency sensors to identify loose parts in operating nuclear reactors, they comply with US NRC and ASME requirements and may be supplied as a hybrid system which also monitors valve flow. Automatic in operation, the systems provide an alarm output when a loose part is detected and record the signal waveform for diagnostic purposes, together with simple to follow graphics depicting the location and characteristics of the indication.
Structural Integrity Monitoring
MISTRAS expertise in structural integrity monitoring includes post-tensioned structures such as secondary containments, roofs and beams, and conventional steel and concrete constructions.
Advanced NDT services provided by MISTRAS include five methods for tubing inspection, including fin-fan and "twisted tubes". Advanced ultrasonic inspection services include automated high speed thickness mapping, at rates of up to three minutes per square metre whilst still providing 100% coverage, and TOFD/PA (time of flight and phased array) services for weld inspection. MONPAC™ AE (acoustic emission) testing provides information on flaw propagation occurring during periodic pressure testing, and AE testing to ASTM and ASME codes is used to ensure the quality and integrity of FRP (Fibre Reinforced Plastic) equipment. The MISTRAS TankPAC™ method monitors the state of active corrosion of storage tank floors, without the need to remove the normal contents, making it the ideal maintenance planning tool, avoiding unnecessary shutdown for cleaning and inspection, with its consequential risk, cost, and damage to the environment.
MISTRAS provides a unique AE testing service to assess the condition of low speed bearings, able to operate even on bearings that take minutes per revolution, and proven in the steel industry over many years. Although usually applied as a periodic test due to the slow degradation of low speed bearings, it is equally effective when used as an on-line monitoring method.
AIMS Engineering Services
MISTRAS also provides engineering services through its AIMS division including fitness for service and RBI (risk based inspection) consultancy and software. MISTRAS PCMS software integrates inspection data management (corrosion, visual, and NDT) with risk based inspection for static plant (pressure systems, valves, and tanks), and links to maintenance management systems such as SAP, providing a convenient and efficient user interface. The RBI component of PCMS is particularly unique since it re-calculates whenever new data is entered or existing data is changed, providing "live" RBI without the need to run costly periodic RBI analysis.