JPWO2019164604A5

JPWO2019164604A5 -

Info

Publication number: JPWO2019164604A5
Application number: JP2020543073A
Authority: JP
Publication date: 2023-10-16
Anticipated expiration: 2039-01-17

Description

組み立て完了済の燃料棒、または端栓部分を圧力室３０内に配置し、ヘリウムなどの高熱伝導性ガスを同室内に導入し、圧力を５００ｐｓｉ程度に上げる。加圧する前に被覆の内部を真空に引いてもよい。圧力室内のガスの圧力が上部端栓内側部品２４に作用して、ばね１４を圧縮するため、ガスがプレナムに充填される。別のやり方として、内側部品２４に外力を印加して押し込むことにより外側部品２２と内側部品２４の間に隙間が形成されるようにしてもよい。そうすると、被覆の内部は自動的に圧力室と同じ圧力のガスで満たされる。次に、選択した時間が経過した後、圧力室の圧力を概ね大気圧まで下げると、被覆内の圧力は上部端栓外側部品２４と貫通口２６の間のメカニカルシールによって上昇後のレベルに維持される。プレナム内の圧力が高ければ高いほど、上部端栓内側部品２４の外壁が貫通口２６の内壁に強く押しつけられ、それらの間のシールが維持される。好ましくは、燃料棒を組み立てる際に、ＳｉＣペーストや黒鉛などの結合剤を貫通口と上部端栓内側部品の境界面に挿入するとシールが改善される。加圧完了後、加圧済み燃料棒を取り出して真空室に入れ、同室内で上部端栓内側部品と貫通口の境界面を、またあらかじめ恒久的なシールを施していない場合は端栓を、恒久的にシールすることができる。
The assembled fuel rod or end plug portion is placed in the pressure chamber 30, and a highly thermally conductive gas such as helium is introduced into the chamber to increase the pressure to about 500 psi. A vacuum may be drawn inside the coating before pressurization. Gas fills the plenum because the pressure of the gas in the pressure chamber acts on the upper end plug inner part 24 and compresses the spring 14. Alternatively, the gap may be formed between the outer part 22 and the inner part 24 by applying an external force to the inner part 24 and pushing it. The interior of the sheath is then automatically filled with gas at the same pressure as the pressure chamber. Then, after a selected period of time, the pressure in the pressure chamber is reduced to approximately atmospheric pressure, and the pressure within the jacket is maintained at the increased level by a mechanical seal between the upper end plug outer part 24 and the through hole 26. be done. The higher the pressure in the plenum, the more the outer wall of the upper end plug inner part 24 will press against the inner wall of the through hole 26, maintaining a seal therebetween. Preferably, during fuel rod assembly, a bonding agent such as SiC paste or graphite is inserted into the interface between the through hole and the upper end plug inner part to improve the seal. After pressurization is complete, remove the pressurized fuel rod and place it in a vacuum chamber, and in the same chamber seal the interface between the inner part of the upper end plug and the through hole, or the end plug if a permanent seal has not been applied beforehand. Can be permanently sealed.

Claims

A method of pressurizing a nuclear reactor core component having a tubular cladding (12) with an upper end and a lower end, the method comprising:
closing the lower end of the sheathing with a lower end plug fitting (16) configured to form an airtight seal;
loading a nuclear reaction element (10) inside the cladding (12) above the bottom end plug (16), leaving an empty plenum (18) inside the cladding and above the nuclear reaction element;
A spring (14) is connected to the upper end of the sheath (12) and configured to bias the nuclear reaction element toward the lower end plug fitting (16) when the upper end of the sheath is closed by the upper end plug fitting (16). inserting into an empty plenum (18) between nuclear reaction elements (10);
closing the top end of the sheathing (12) with a top end plug fitting (16) comprising a top end plug outer part (22) and a top end plug inner part (24); 24) slides inside the through hole (26) of the upper end plug outer part (22), and the upper end plug fitting (16) forms an airtight seal at the contact point of the upper end plug with the covering (12). When the upper end of said sheathing is at least partially closed, the lower end is configured to bias the spring (14) towards the nuclear reaction element (10), connecting the through hole (26) and the upper end plug inner part (24). ) is configured such that the upper part of the inner part of the upper end plug fits into the through hole but cannot come out of the upper part of the through hole, and the spring (14) pushes the inner part of the upper end plug (24). the upper end plug inner part and the through hole form a substantially airtight seal at the uppermost position within the through hole in which the upper end plug inner part is movable; a covering upper end closing step, which is configured to form a gas flow path below the upper limit position;
placing at least the upper end of the sheathing (12) into the pressure chamber (30) with the upper end plug fitting (16) and the lower end plug fitting (16) in place ;
introducing a filler gas into the pressure chamber (30);
increasing the pressure of said filler gas in the pressure chamber (30) to a preselected pressure for a predetermined period of time;
sealing the top end plug inner part (24) to the top end plug outer part (22);
including;
A method, wherein the step of sealing the upper end plug inner part (24) to the upper end plug outer part (22) is performed by reducing the pressure of the fill gas in the pressure chamber (30) after a predetermined period of time.

The method of claim 1, including the step of permanently sealing the upper end plug fitting (16) and the lower end plug fitting (16) to the cladding (12).

the step of removing the sheath (12) with the upper end plug fitting (16) and the lower end plug fitting (16) from the pressure chamber (30) after a predetermined period of time; 3. The method of claim 2, further comprising the step of permanently sealing the fitting and the lower end plug fitting to the sheathing.

4. The method of claim 3, including the step of permanently sealing the top end plug inner part (24) to the top end plug outer part (22) after said ejecting step.

1 . The step of closing the lower end of the sheathing ( 12 ) and the step of closing the upper end of said sheathing are carried out using a clamp ( 28 ) or other device for pressing said upper end plug outer part against the sheathing ( 12 ). the method of.

6. The method of claim 5, wherein the clamp (28) is a mechanical or hydraulic fastener.

2. The method of claim 1, including the step of applying a bonding agent to the interface between a wall of the through opening (26) and an adjacent wall of the upper end plug inner part.

8. The method of claim 7, wherein the binder comprises one or more of SiC paste, graphite, silver, titanium, or aluminum.

2. The method of claim 1, including the step of evacuating the pressure chamber (30) prior to the step of introducing the fill gas into the pressure chamber (30) and after the step of installing the coating.

The method of claim 1, including the step of mechanically attaching the upper end plug outer part (22) to the sheathing (12).

a silicon carbide tubular jacket (12) having an upper end and a lower end;
an upper end plug (16) for sealing the upper end;
A core component of a nuclear reactor including a lower end plug (16) sealing the lower end, wherein the tubular cladding has a nuclear reaction element (10) lower inside thereof, an upper end plug (16) and a nuclear reactor. a spring (14) extending between the reaction elements (10) and biasing the nuclear reaction elements towards the lower end plug (16), the upper end plug containing the upper end plug outer part (22); Consisting of an upper end plug inner part (24),
The upper end plug inner part (24) slides inside the through hole (26) of the upper end plug outer part (22), and the upper end plug fitting (16) brings the upper end plug into contact with the covering (12). The lower end is configured to bias the spring (14) towards the nuclear reaction element (10) when the upper end of the sheath is at least partially closed by forming an airtight seal at the opening (26) and the upper end. The end plug inner part (24) is configured such that the upper part of the upper end plug inner part fits into the through hole but cannot come out from the upper part of the through hole, and the spring (14) The inner part (24) is supported so as not to fall out from the through hole (26), and the upper end plug inner part and the through hole are substantially at the upper limit position within the through hole in which the upper end plug inner part is movable. The upper end plug inner part (24) is configured to form an airtight seal and a gas flow path below the upper limit position, and the upper end plug inner part (24) is connected to the upper end plug outer part (24) after the inside of the covering (12) is pressurized. 22) configured to be permanently sealed to the
Nuclear reactor core components.

12. The nuclear reactor core component of claim 11 , wherein the nuclear reactor core component is a fuel rod.

12. The nuclear reactor core component of claim 11 , wherein the nuclear reactor core component is a control rod.

The through hole (26) of the upper end plug outer part has a truncated conical inner wall, and the outer wall of the upper end plug inner part (24) in contact with the inner wall has a truncated conical shape. 12. The nuclear reactor core component of claim 11 , wherein the minimum diameter is greater than the minimum diameter of the frustoconical inner wall.

The method of claim 1, wherein the plenum is filled with the fill gas so that the fill gas acts on the upper end plug inner part (24) to compress the spring (14).

2. The method of claim 1, wherein the tubular sheath is made of silicon carbide.

In the step of sealing the upper end plug inner part (24) to the upper end plug outer part (22), the upper end plug inner part (24) is in the upper limit position and a portion of the upper end plug inner part (24) is in the upper end plug outer part (22). 2. The method of claim 1, further comprising: extending inside said through-hole with a remaining portion extending beyond said upper end plug outer part.

In the upper limit position of the upper end plug inner part (24), a part of the upper end plug inner part extends inside the through hole, and the remaining part protrudes from the upper end plug outer part (22); The nuclear reactor core component of claim 11 .