Advanced Test Reactor
1964 film, with transcript
Catalog description: This film shows precisely how the AEC's 250-Mwt Advanced Test Reactor design utilizes multiple flux traps to achieve exceptionally high neutron density in nine independent test loop positions. Animations de- scribe the clover leaf, enriched fuel annulus that circumscribes the nine flux trap test positions, and the moving control components which vary flux and power in each test position. ATR was designed by Ebasco Services, Inc., as prime contractor, with Babcock & Wilcox Co. as nuclear subcontractors. Phillips Petroleum Co. pre- pared the conceptual design, and will operate the reactor.
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Show transcript
| 00:00 | The Advanced Test Reactor. |
| 00:30 | Predictions of the lifetime characteristics of materials operating in a reactor environment |
| 00:38 | is made possible by accelerated irradiation in test reactors. |
| 00:50 | One of the first test reactors is the 40 megawatt materials testing reactor. |
| 00:59 | This design achieves neutron fluxes of 3 times 10 to the 14th fast neutrons per square centimeter |
| 01:05 | per second. |
| 01:14 | The 175 megawatt engineering test reactor attains fluxes of 9 times 10 to the 14th fast |
| 01:21 | neutrons per square centimeter per second. |
| 01:30 | The ATR will provide even more severe test environments. |
| 01:39 | The ATR uses the flux trap concept, which produces high flux in an experimental region |
| 01:45 | surrounded by fuel. |
| 01:52 | Placing several of these flux traps in a single pressure vessel is a logical extension of |
| 01:56 | this concept. |
| 01:59 | Economies are possible by combining five flux traps in a single core with one control system |
| 02:04 | and one set of auxiliary hardware. |
| 02:08 | Finally, a serpentine fuel configuration evolves, providing multiple flux traps in an efficient |
| 02:16 | circular geometry. |
| 02:21 | The ATR will operate at 250 thermal megawatts, achieving experimental peak fast fluxes of |
| 02:28 | 1.5 times 10 to the 15th fast neutrons per square centimeter per second. |
| 02:35 | There are five 50 megawatt fuel regions, the four lobes, and the center region. |
| 02:44 | The core configuration provides nine six-inch flux traps. |
| 02:48 | Each trap surrounds an experiment pressure tube. |
| 02:57 | The flux spectrum in any trap can be modified by changing the composition of the moderating |
| 03:01 | material. Lobe power can be varied from 40 to 60 megawatts. This power tilt is |
| 03:14 | achieved principally by rotating beryllium shim cylinders which have a |
| 03:18 | hafnium plate covering one-third of their surfaces. As the cylinders are |
| 03:25 | rotated, the desirable constant vertical cosine flux distribution is maintained. |
| 03:31 | As fuel is consumed, power distribution is maintained by further movement of the cylinders |
| 03:38 | and of hapnium-necked shim rods. |
| 03:42 | Individual rods are either fully in or out, and do not alter vertical flux distribution. |
| 03:53 | To achieve its advanced performance, the ATR uses special fuel, control components and |
| 03:59 | support structures. |
| 04:04 | A major vertical support and alignment structure is the aluminum neck shim housing, which is |
| 04:09 | drilled to receive haptium shim rods. |
| 04:15 | It supports the flux trap baffle tubes. |
| 04:19 | The baffle tubes surround each of the nine experiment pressure tubes. |
| 04:26 | Cylindrical safety rods surround the pressure tubes. |
| 04:30 | The rods have an upper hafnium poison section. |
| 04:34 | Removable inserts in the follower are used to vary the neutron moderation. |
| 04:39 | The rods are driven from below the core by a rack and pinion. |
| 04:47 | operation the poison section is above the core, the aluminum follower is in the |
| 04:51 | flux trap region. When the reactor is scrammed, the rods drop under the |
| 04:58 | combined action of gravity, spring, and hydraulic forces. Safety rods can be |
| 05:05 | placed in any one of eight positions. On the basis of critical tests, only five |
| 05:10 | safety rods are installed. |
| 05:17 | The 24 hafnium neck shim rods are driven from below. |
| 05:25 | Two rods are used to provide fine regulating control. |
| 05:29 | The other neck rods are used as full-in or full-out shim rods. |
| 05:37 | The 16 outer shim cylinders operate in pairs. |
| 05:40 | They are driven from above the core. |
| 05:57 | The fuel annulus is made up of 40 elements, each 48 inches long. |
| 06:05 | Each 45 degree fuel element sector contains 19 equally spaced curved plates. |
| 06:11 | The aluminum clad fuel is uranium oxide dispersed in an aluminum matrix and contains boron carbide |
| 06:18 | as burnable poison. |
| 06:28 | The complete core is surrounded by a beryllium reflector. |
| 06:32 | The holes in the reflector are used for static irradiation experiments. |
| 06:38 | The core assembly is contained within a cylindrical aluminum tank, |
| 06:42 | supported through a series of tanks from the reactor pressure vessel bottom head. |
| 06:51 | Water coolant enters the lower part of the reactor vessel, |
| 06:55 | upward through the thermal shields and then flows downward through the core and |
| 07:01 | reflector. The coolant is then diverted to four 16-inch outlet pipes. Test |
| 07:10 | specimens may be irradiated in loops using water, gases, or liquid metal |
| 07:16 | coolants at temperatures and pressures expected in the most advanced power |
| 07:21 | reactors. |