Nuclear reactors and control means
Reference is made to control means for reactors having vertical channels for control rods. In an emergency the core could become distorted so that the rods cannot be fully injected into the channels to effect immediate shutdown. In some cases additional channels are provided, with means for injecting boron steel balls on receipt of an emergency signal; disadvantages of this arrangement, however, are stated. In the system described the control means comprises an elongated canister having a lower portion slidable with clearance in the channel and an upper portion having a crosssection greater than the cross-section of the channel. The canister contalns balls of material of high neutron absorption cross-section, retained within both portions of the canister against gravity by a lower closure member. The canister is suspended by the closure member with its lower end closed and in alignment with the channel, so that its lower portion is variably positionable within the channel by means sensitive to reactor characteristics for the purpose of reactivity control. The closure member is arranged so that in the event of the lower portion of the canister becoming jammed during downward movement the closure member continues to move downward, releasing the balls to effect complete reactor shutdown. The arrangement provides that the normal control means can also be utilized for emergency shutdown, without the provision of additional channels, thereby saving reactor space and reducing instrumentation. Since the balls are normally retained within the canister they are readily recoverable after a spurious shutdown. (UK)
- Research Organization:
- Originating Research Org. not identified
- NSA Number:
- NSA-29-012199
- OSTI ID:
- 4392712
- Report Number(s):
- GB 1325503
- Resource Relation:
- Patent File Date: 1971 Jun 28; Other Information: Orig. Receipt Date: 30-JUN-74; Bib. Info. Source: UK (United Kingdom (sent to DOE from))
- Country of Publication:
- United Kingdom
- Language:
- English
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