AUMA SAI-SARI Nuclear Multi-Turn Actuator (Inside Containment)

Overview

AUMA SAI-SARI is the AUMA multi-turn actuator range for valves inside the containment of nuclear power plants, the most demanding location in the plant. SAI actuators serve open-close and positioning duty and SARI actuators modulating duty over a torque range of 10 Nm to 6,400 Nm, and the whole family is qualified in compliance with IEEE 382-2006. The DBE-resistant AUMA SAI-SARI can take over safety functions under design basis event conditions, surviving a loss-of-coolant accident profile of up to 220 °C and 6 bar absolute together with very high radiation doses.

In Oman and the GCC, Seven Star LLC supplies the AUMA SAI-SARI to nuclear EPC contractors, plant owners and power-sector customers in the Sultanate of Oman and the wider GCC. Inside-containment equipment is delivered against project-specific qualification, documentation and quality assurance requirements, so our Muscat team coordinates certificates, test reports and configuration directly with AUMA from the first enquiry.

Working Principle of the AUMA SAI-SARI

The AUMA SAI-SARI uses the AUMA modular principle: a 3-phase AC motor with a special winding resistant to the higher temperatures and radiation expected during a LOCA or DBE drives a gear train, while a control unit counts turns per stroke and records torque, so the actuator switches off at the end position or on torque overload. A dog coupling and an internal motor plug/socket connector allow fast motor replacement. The actuator is self-locking even during manual operation by the steel handwheel, which is provided for emergency operation after loss of power.

Under accident conditions the housing sees pressure and temperature swings, so the SAI/SARI is fitted with an air vent valve that minimises the pressure difference between the gear compartment and the environment. The outside parts contain no aluminium: the motor housing, the switch compartment cover and the electrical connection cover are made of spheroidal graphite cast iron or grey cast iron and the handwheel is steel, which keeps the actuator intact at temperatures where aluminium would fail.

Engineering Design of the AUMA SAI-SARI

The SAI range includes SAI 07.2, 07.6, 10.2, 14.2, 14.6, 16.2, 25.1, 30.1 and 35.1 with speeds of 4 to 180 rpm at 50 Hz, tripping torque ranges from 10–30 Nm to 2,500–6,400 Nm and output flanges from F07 to F35 according to EN ISO 5210. The SARI modulating range runs from SARI 07.2 to SARI 30.1 with speeds of 4 to 45 rpm (4 to 11 rpm on the largest sizes), maximum modulating torque from 15 Nm to 1,280 Nm and up to 1,200 starts per hour on the smaller sizes, reduced to 300 on SARI 25.1 and 30.1.

Qualification covers vibration, OBE and SSE seismic profiles (6 g line-mounted and 9 g hard-mounted), radiation of 1.05 x 10 to the power of 6 Gy during operation and 1.2 x 10 to the power of 6 Gy under LOCA/DBE for a total of 2.25 x 10 to the power of 6 Gy, and LOCA testing at 220 °C and 6 bar, with SAI 30.1 additionally tested for long-term DBE. The plant lifetime is rated at 60 years at 60 °C, with 3,000 to 4,000 operating cycles for SAI and 375,000 to 500,000 starts for SARI. Enclosure protection is IP68, corrosion protection is class KS, and an intermediate frame for double sealing is standard.

Key Features

The following characteristics define the AUMA SAI-SARI range:

• Qualification in compliance with IEEE 382-2006 supports use inside the containment of nuclear power plants.
• DBE resistance up to 220 °C and 6 bar absolute enables the actuator to perform safety functions during and after an accident.
• Radiation resistance of up to 2.25 x 10 to the power of 6 Gy total dose is documented for operational and LOCA/DBE exposure.
• A torque range of 10 Nm to 6,400 Nm covers gate and globe valves from small to very large.
• A special high-temperature, radiation-resistant motor winding and an air vent valve protect the actuator in accident conditions.
• No aluminium in the outside parts: cast-iron housings and a steel handwheel for temperature resilience.
• Plant lifetime is rated at 60 years at 60 °C with SAI qualified for 3,000 to 4,000 operating cycles.
• Options such as stem protection tube, wet paint, mechanical position indicator and DBE-resistant cable entries tailor the actuator to the project.

Industrial Applications

The AUMA SAI-SARI is designed for valves inside the reactor containment: containment isolation, safety injection and emergency cooling systems, residual heat removal and other circuits that must operate during or after a LOCA or DBE. The actuators can also be combined with GSI part-turn and GSTI multi-turn gearboxes and LEN linear thrust units to automate butterfly, ball, plug, gate and globe valves with a single qualified actuator family.

Beyond nuclear plants, the same design philosophy of radiation, temperature and seismic resilience is of interest to specialist facilities and research installations. In Oman and the GCC, Seven Star LLC supplies the AUMA SAI-SARI to customers in Oman and the GCC with documentation and qualification support; the supply of nuclear equipment remains subject to the relevant regulatory, export and project-specific requirements, which we clarify with the customer and AUMA before quotation. If the AUMA SAI-SARI is not the closest fit for a valve, see the AUMA SAN-SARN, the AUMA SA 10.2 multi-turn actuator or the AUMA GS part-turn gearbox for alternatives from the same AUMA family.

Technical Specifications

The table summarises the main data of the AUMA SAI-SARI from the AUMA product page and the AUMA brochure on actuators for nuclear power plants (March 2025).

Request a Quote for AUMA SAI-SARI

To enquire about the AUMA SAI-SARI for use inside containment, send Seven Star LLC the valve data, required torque and duty, voltage and frequency, and the qualification, ageing and documentation requirements of your specification. We will liaise with AUMA and return an RFQ response, and the AUMA nuclear brochure can be downloaded from this page. In Oman and the GCC, we handle these project-specific orders with manufacturer documentation.