AUMA SAN-SARN Nuclear Multi-Turn Actuator (Outside Containment)

Overview

AUMA SAN-SARN is the AUMA multi-turn actuator range designed for the automation of valves in nuclear power plants outside the containment. The SAN actuators handle open-close and positioning duty, and the SARN actuators modulating duty, across a torque range of 10 Nm to 6,400 Nm. The range is qualified in compliance with IEEE 382-2006, and the DBE-resistant design allows the AUMA SAN-SARN to take over safety functions under design basis event conditions, which is why it is specified for safety-related and important-to-safety valves in the turbine hall, auxiliary buildings and other areas outside the reactor containment.

In Oman and the GCC, Seven Star LLC supplies the AUMA SAN-SARN to nuclear and power-sector EPC contractors and operators in the Sultanate of Oman and the wider GCC. Nuclear projects demand documented traceability, quality assurance and certificates from the start, so our Muscat team works with the customer and AUMA to confirm the project-specific qualification, documentation and approval requirements before an order is placed.

Working Principle of the AUMA SAN-SARN

The AUMA SAN-SARN follows the same modular principle as the AUMA SA range: a 3-phase AC motor drives a gear train and output drive, while a control unit records the number of turns per stroke and the tripping torque, signalling the controls when the end position is reached or the torque limit is exceeded. Limit and torque sensing, a handwheel for manual operation and an optional mechanical position indicator are included, and the actuator is sized for the specified service conditions rather than the maximum catalogue torque.

What makes the range nuclear-grade is its qualification. AUMA qualified the SAN by analysis on the basis of the SAI test programme, since the basic design features of the two ranges are identical, and the certification confirms the requirements for use outside the containment. The actuators were tested for vibration and seismic loads (OBE and SSE), radiation exposure and a LOCA/DBE profile of up to 120 °C at 1.34 bar absolute, and a lifetime test supports a plant service life of 40 years at 40 °C.

Engineering Design of the AUMA SAN-SARN

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

Radiation resistance during operation is rated at 5 x 10 to the power of 4 Gy. Enclosure protection is IP68, meaning continuous immersion up to 8 m for a maximum of 96 hours with up to ten operations, and corrosion protection is class KS. Ambient temperature is –30 °C to +80 °C, the electrical connection uses the AUMA plug/socket connector with terminals as an option, and options include a stem protection tube, wet paint and mechanical position indicator. Standard motor protection is by thermoswitches, and AUMA states the noise level as below 72 dB(A).

Key Features

The following characteristics define the AUMA SAN-SARN range:

• Qualification in compliance with IEEE 382-2006 supports use in safety-related nuclear applications outside containment.
• DBE-resistant design with LOCA/DBE capability up to 120 °C and 1.34 bar absolute allows safety functions to be performed under event conditions.
• A torque range of 10 Nm to 6,400 Nm covers gate and globe valves from small to very large.
• SAN actuators serve open-close and positioning duty, and SARN actuators serve modulating duty in class C.
• Seismic qualification includes OBE and SSE vibration profiles, with hard-mounted resistance up to 9 g.
• Sizing for a plant service life of 40 years at 40 °C with 3,000 to 4,000 operating cycles for open-close duty.
• IP68 enclosure protection and KS corrosion protection suit humid and washdown conditions.
• Combinations with GSI part-turn gearboxes, GSTI multi-turn gearboxes and LEN linear thrust units extend the range to butterfly, ball, plug and globe valves.

Industrial Applications

The AUMA SAN-SARN automates valves located outside the reactor containment in nuclear power plants: main steam and feedwater isolation, auxiliary and emergency feedwater, service-water and component cooling systems and other balance-of-plant duties where qualified actuators are required. The ability to combine with GSI part-turn and GSTI multi-turn gearboxes and LEN linear thrust units means the same actuator family can be applied to butterfly, ball, plug, gate and globe valves.

For the wider Gulf region, this range is relevant to EPC contractors and plant owners who procure internationally qualified equipment for nuclear energy programmes and associated plants, and to research and specialist facilities. In Oman and the GCC, Seven Star LLC supplies the AUMA SAN-SARN with documentation support and coordinates certificates, test reports and project-specific qualification requests with AUMA; the supply of nuclear equipment remains subject to the relevant regulatory and export requirements. For projects that combine the AUMA SAN-SARN with other drives or controls, Seven Star LLC also supplies the AUMA SAI-SARI, the AUMA SA 07.2 multi-turn actuator and the AUMA GS part-turn gearbox.

Technical Specifications

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

Request a Quote for AUMA SAN-SARN

For an enquiry on the AUMA SAN-SARN, send Seven Star LLC the valve data, required torque and duty, voltage and frequency, and the qualification and documentation requirements in your project specification. Our instrumentation division will coordinate with AUMA and return an RFQ response; the AUMA nuclear brochure with the technical data is available for download here. In Oman and the GCC, we advise on lead times for these project-specific orders.