Immediate Modifications

The vessel plug had been designed to take several positions depending on a servosystem related to temperature and pressure measurements. This proved far too complex and moved when it was not required to do so. It was altered to a fixed position for simplicity.

The high-speed argon blowers were changed for conventional low-pressure

image211

Fig. 4.31. Cross section of the Rapsodje Reactor (39).

Identification Key for Fig. 4.31

Code no.

Position

Description

1

E5

Leaktight vessel

2

E6

Stereotopographical measurement position

3

B4-F4

Loop pipes (inlet and southern outlet)

4

A4

Nitrogen supply pipe for interspace II

5

G4

Southern purification loop

6

E5

Preheating jacket

7

C4

Nitrogen distribution annulus

8

C6

Preheating jacket keying

9

E4

Thermal shield

10

A4

Fill and drainage pipe

11

C4

Siphon breaker

12

E4

Safety injection pipe

13

D6

Support grid

14

D5

Neutron shield

15

D6

Diffuser

16

D7

Annular diaphragm

17

F6

Guard vessel

18

G7

Outer boundary

19

C2

Thermal deck

20

E3

Large rotating plug

21

D3

Small rotating plug

22

D2

Control plug

23

B1

Support flange for rotating plugs and leaktight vessel

24

B2

Support plate

25

E3

Anti-sodium barrier

26

El

Liquid joint

27

El

Lip joint

28

D5

Fuel assembly

29

E5

Breeder assembly

30

D5

Control rod

31

E4

Core cover

32

D3

Control rod guide tube

33

D1

Drive mechanism housing

34

D4

Handling guide tube

35

Ordinary concrete (d = 2.3)

36

Normal borated concrete (d = 2.8)

37

Heavy baryted concrete (d = 3.5)

38

Metallic insulation concrete (d = 5.4)

39

Rare earth concrete (d = 2.4)

Fluids used:

: cover gas—

-argon; main coolant—sodium; other interspace and preheat-

ing fluids—

-argon and nitrogen.

blowers with oil bearings. The more advanced components had previously been sticking.

Some of the previously inerted vaults below the operating floor were changed to air for convenience, although nitrogen was still retained within the reactor vault and around the primary system.

The air conditioning system within the containment began giving rise to a water collection problem that had originally not been recognized as a possibility. This problem was solved before start-up with the sodium — cooled reactor.