Battelle Energy Alliance, LLC (BEA), Management and Operating Contractor of the Idaho National Laboratory, seeks an expression of interest from qualified subcontractors to design functionally equivalent replacements for four nuclear instrumentation subsystems at the Advanced Test Reactor (ATR). The four subsystems are 1) the Log Count Rate Meter (LCRM) subsystem, 2) the Wide Range Neutron Level (WRNL) subsystem, 3) the Neutron Level (NL) and NL No. 8 subsystem, and 4) the Log-N Period subsystem. The following components are included in the design effort: the detectors, displays/recorders, amplifiers, associated electronics of each subsystem, and all appropriate equipment interfaces.
Battelle Energy Alliance, LLC
Idaho National Laboratory
2525 N. Fremont Avenue
P.O. Box 1625
Idaho Falls, ID 83415
Telephone: (208) 526-7374
Commercially available equipment, either off-the-shelf or customized, may meet the technical and functional requirements of this procurement. ATR's unique construction and operation, however, necessitate a rigorous design. The intent of this request for expression of interest and subsequent procurement activities is to develop a complete design for the four subsystems, incorporating details and nuances of the ATR. The design will be used in a separate procurement activity to acquire and install the equipment.
The purpose of this request is to identify interested candidates that possess the qualifications to design the nuclear instrumentation, from concept through final design. The qualified responders will receive a formal request for proposal for the work. The request for proposal will include technical and functional requirements for the four subsystems. The eventual design may include off-the-shelf, modified off-the-shelf, or custom components, provided that they meet the technical and functional requirements.
The Advanced Test Reactor (ATR) is a pressurized water reactor whose principal function is to provide a high neutron flux for experiments involving reactor fuels and materials. The reactor, owned by the U.S. Department of Energy, has a design thermal power of 250 MW. Its nominal inlet pressure and temperature are 360 psig and 125°F. The nominal core outlet temperature is 170°F at the design thermal power level. The ATR and its support facilities are located at the ATR Complex at the Idaho National Laboratory.
The ATR supports many different experiment programs. Irradiation experiments in ATR fill a vital role in the development of naval reactors and are expected to play an important role in the development of new reactors. To support safe and reliable operation of the ATR, the Idaho National Laboratory initiated the ATR Life Extension Project in 2006. Early project activities included a material condition assessment of selected ATR components. The assessment identified the items requiring attention to mitigate various aging effects. The assessment identified various nuclear instrumentation subsystems requiring improvement, including the four subsystems addressed by this request for expression of interest. The following paragraphs provide some technical information about the subsystems.
Log Count Rate Meter (LCRM) Subsystem
The LCRM subsystem provides information to plant operators concerning low-level neutron flux and flux changes in the core. The information minimizes the threat of an unplanned criticality. In addition, the subsystem provides ATR operators with information about the neutron flux levels and flux changes during startup.
The dual channel LCRM subsystem uses two fission chambers to provide signals that monitor neutron population. When the reactor is at power, the LCRM system is secured and the associated fission chambers are withdrawn from the core region.
The existing LCRM subsystem uses a fission chamber operated in current mode. The electronics in each LCRM channel consist of the following items:
•· a solid-state preamplifier located in the nozzle trench, assembled from commercially available parts;
•· a solid-state LCRM module mounted in the amplifier cabinet,
•· a power supply module mounted in the amplifier cabinet, which supplies power to the individual channels, and
•· an isolation transformer mounted in the amplifier cabinet.
The existing LCRM subsystem uses two Leeds and Northrop pen and paper chart recorders in the reactor control room, as well as count rate meters and speakers on the reactor top and output to the Console Display System.
Wide Range Neutron Level (WRNL)
The safety-related WRNL subsystem monitors neutron flux from 10 to 5e9 nv and is one of several analog subsystems that form the Plant Protection System (PPS). It monitors thermal neutron levels and their rate of change, providing a reactor shut-down signal when the reactor period is less than a preset limit or when the flux level exceeds a threshold.
The subsystem comprises three channels, each consisting of a compensated ion chamber (CIC), a preamplifier, an electronics drawer, various switches, a power supply, a control room recorder and output to the Console Display System. The electronics drawer automatically selects one of 12 zero-based ranges from 10 to 5e9 nv. The WRNL drawer and pre-amplifier have combined response times of less than 2.5 msec for ranges 9 through 12 and 12.5 msec for ranges 1 through 8, both for an input step change of 67% full scale to 88% full scale with the setpoint at 80% full scale. The existing WRNL subsystem uses three Leeds and Northrop pen and paper chart recorders to provide a Reactor Control Room display.
Neutron Level and Neutron Level No. 8 Subsystem
The safety-related Neutron Level subsystem monitors neutron flux from 5e4 to 5e9 nv during pressurized and depressurized (factor of 100 less) operations. The Neutron Level Drawer incorporates three independent gains of 100x, 1-2x, 1x. The drawer displays 2.5 decades of range. It also provides a reactor shutdown signal to the PPS when the thermal neutron flux exceeds a threshold. The system comprises three channels, each consisting of an uncompensated ion chamber, a preamplifier, an electronics drawer, various switches, a power supply, a control room chart recorder and an output to the Console Display System display. The drawer and pre-amplifier have combined response times of less than 2.5 msec.
The Neutron Level No. 8 subsystem, though not a part of the PPS, monitors neutron flux over the reactor power range and provides a signal for a non-safety related power reduction. The NL No. 8 subsystem provides a fourth neutron level channel which, in combination with the NL subsystem, provides indication of neutron level in all four quadrants of the reactor core. The subsystem provides a method to monitor reactor power variations. The NL No.8 subsystem is comprised of the same components as the individual NL channels: an uncompensated ion chamber, a preamplifier, an electronics drawer, a power supply, and a control room recorder.
The Neutron Level and Neutron Level Number 8 subsystems use four Leeds and Northrop pen and paper chart recorders to provide a Reactor Control Room display.
Log-N Period Subsystem
The Log-N Period Subsystem comprises two channels, each consisting of a CIC, a power supply, a Log-N Period amplifier, a Log-N recorder, and a Period recorder. The readout information of reactor period and power level is provided on two Log-N recorders and two Period recorders. The recorders re-transmit the signal to the Reactor Data Acquisition System, which then forwards a signal to the Console Display System. The Log-N Period subsystem supports the Reactivity Control/Safety Rods System by providing signals to restrict, inhibit, or permit safety rod, Outer Shim Control Cylinder, and neck shim withdrawal under various reactor power level scenarios. Further, the Log-N Period subsystem supports the Control Power Reduction Subsystem by providing a reactor power reduction signal through the period recorder. The Log-N portion of the system is safety related, as it provides an indication of initial conditions during low power operation.