MOHR Introduces Precision Nuclear Spent Fuel Pool Level Monitoring System

Remote Monitoring System to Help Avert Future Fukushima-Type Nuclear Accidents

MOHR Test and Measurement LLC (MOHR), an innovator of multiphase flow instrumentation for nuclear and other industrial applications, today announced three additions to its EFP Series guided UWB radar liquid level instrumentation family. The panel-mount EFP-IL signal processor, portable EFP-HL signal processor, and SFP-1 Spent Fuel Pool Probe Assembly are targeted at nuclear applications.

MOHR offers the products as an ideal solution for the recent U.S. Nuclear Regulatory Commission (NRC) requirement that reliable spent fuel pool monitoring equipment be installed in all 104 U.S. commercial nuclear reactors (NRC Order EA-12-051), issued in response to the Japan nuclear accident at Fukushima Dai-ichi in March 2011. Spent fuel pool level monitoring helps prevent exposure and overheating of spent nuclear fuel rods that could lead to the spread of radioactive debris during accident conditions.

EFP-IL and EFP-HL Signal Processors

The EFP-IL and EFP-HL provide a unique solution for the NRC spent fuel pool monitoring requirement because both instruments can monitor liquid level remotely, with demonstrated sensitivity of approximately 3 mm (0.1 in.) through more than 300 m (1000 ft.) of cable. Remote monitoring helps avert damage to system electronics that might otherwise occur during nuclear accident conditions, for instance during the earthquake, tsunami, and hydrogen explosions that occurred at the Fukushima facility.

The EFP-IL and EFP-HL instruments utilize MOHR’s proprietary Electric Field Perturbation (EFP) technology and boast instrument precision and accuracy of 0.1 mm (0.004 in.) and 1 mm (0.04 in.), respectively (excluding probe surface tension effects), with real-world system accuracy better than 12.5 mm (0.5 in.) for routine industrial applications. The instruments also provide sophisticated leak detection and monitoring capabilities.

The EFP-IL is a panel-mount instrument with rugged NEMA 4X enclosure designed for fixed installation, and the EFP-HL is a portable instrument with rugged IP67-rated case designed to be used at a remote monitoring location. The EFP-HL can operate from its replaceable internal battery for more than 6 hours or indefinitely from external batteries. Both instruments are designed to connect to the SFP-1 probe through armored coaxial cable and provide Ethernet and USB communications; the EFP-IL also offers optional 4-20 mA and level alarm relays.

The SFP-1 probe assembly is a cantilevered unibody design that meets stringent MIL-SPEC shock and vibration requirements using components that have demonstrated long life at nuclear temperatures and pressures. The probe assembly is designed to mount to the rim of the spent fuel pool, extending to the bottom of the pool without modification to the pool liner. The body of the SFP-1 probe sheds debris and can provide reliable full-scale continuous level monitoring even in the presence of seawater or other contaminants. The probe can be used in both BWR and PWR spent fuel pools.

Pricing and Availability

Delivery of the EFP-IL, EFP-HL, and SFP-1 probe assembly is anticipated Q2 2013, subject to site-specific engineering requirements and regulatory approval, pricing competitive with other manufacturers’ solutions. To learn more about MOHR EFP Series instruments please visit

About MOHR

MOHR (formerly Mohr and Associates) has developed innovative test and measurement instrumentation for commercial and military nuclear applications for nearly 30 years. Learn more at

Media Contact:
Brandt Mohr
+1 (888) 852-0408

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