DE1184872B - A pulsed neutron source designed as a fast reactor - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Boarding school Class: G 21

German class: 21g-21/12

Number: 1184 872 -

File number: E 25343 VIII c / 21 g

Filing date: August 15, 1963

Opening day: January 7, 1965

The invention relates to a pulsed neutron source designed as a rapid reactor two neutron exit windows in the reflector and with separate ones that move past the windows, synchronized umbrellas, made of substances that increase reactivity. This, already proposed by a third party Construction is particularly advantageous for structural and operational reasons than those for the same purpose — but essential smaller output - well-known Russian system »IMR-DUBNA«.

The Russian facility has two disks on which elements influencing the neutron flux are upset. One disk runs through the center of the cleavage zone, while the other is at Turned past the edge of this zone. This system can only be used for small services, as it is an effective one Cooling of the wafers leading through the gap zone is difficult to achieve.

The reactivity is pulsed in two stages: in the first stage one of the screens pulsates on its own Windows the reactor close to the criticality (pre-pulse), in the second stage the other pulse Screen at his window the reactor beyond the prompt criticality (excess pulse). The screen for the excess pulse, the duration of the reactivity pulse determines the duration of the reactivity pulse, the screen for the pre-pulse determines the Frequency of the neutron pulses. The aim is to make the pulse duration as short as possible.

According to the invention, in reactors with two windows with respect to the pulse duration of the Neutron impact good results if the window for the excess pulse at least as a single, against the window for the pre-pulse screen is designed with a narrow gap. The window has a line of Columns, the mutual spacing of which increases or decreases, and shows the associated screen accordingly with congruent zones on reactivity-increasing material, then a sufficient one becomes Reactivity stroke guaranteed and a decoupling between stroke amplitude and pulse width achieved.

The drawing illustrates, in a highly schematic manner, one exemplary embodiment for each of the above Solutions. It shows

F i g. 1 an arrangement with a window and a single gap and

F i g. 2 an arrangement with window and column line.

In Fig. 1 denotes 10 the reactor core, 11 the window and 12 the gap according to the invention. The screens 13, 14 with the axes of rotation 15, 16 are formed as a faster reactor,
pulsed neutron source

Applicant:

European Atomic Energy Community (EURATOM),

Brussels

Representative:

Dipl.-Ing. R. Müller-Börner,

Berlin 33, Podbielskiallee 68,

and Dipl.-Ing. H.-H. Wey, Munich 22,

Patent attorneys

Named as inventor:

Dipl.-Phys. Gustav Kistner, Freiburg (Breisgau); Dipl.-Phys. Rolf Misenta, Varese;

Victor Raievski, Ispra, Varese (Italy)

because of being on circular paths in front of the window and gap. The length of the screen 14 is in the direction of movement adapted to the gap width. In order to ensure the required reactivity boost, it may be expedient to construct the screen 14 from fissile material.

In Fig. 2 denotes 20 the reactor core, 21 the window for the prepulse, 22 the slit line for the excess pulse, 23 and 24 denote the screens. The screen 24 is provided with reactivity-increasing material corresponding to the gap line 22 only in zones at the points 25. The excess pulse generated when the gap is completely covered is n times greater than the pulse of an individual gap (n = number of gaps).

The two-window reactor has the advantage over the single-window reactor that each of the screens so work as close as possible to the window and the thickness can be made weaker.

Claims (2)

Patent claims: 1. A pulsed neutron source designed as a fast reactor, with two neutron exit windows in the reflector and with separate, synchronized screens that move past the windows, from reactivity-increasing substances, for pulsing the reactivity in two stages; in the first step at a window up to the vicinity 409 767/265 the criticality (pre-pulse), in the second stage at the same time at the other window via the prompt criticality (excess pulse), characterized in that the window for the excess pulse at least as a single one, narrower towards the window for the pre-pulse screen Gap is formed. 2. Neutron source according to claim 1, characterized in that the window has a line of Has columns whose mutual spacing increases or decreases, and that the associated Screen has reactivity-increasing material only in the areas assigned to the columns. Documents considered: Austrian Patent No. 224 768; U.S. Patent No. 2,790,761; "Nuclear Energy", 2nd vol., No. 8, 1959, pp. 705, 706. 1 sheet of drawings 409 767/265 12.64 © Bundesdruckerei Berlin