JPH0344276B2 - - Google Patents
Info
- Publication number
- JPH0344276B2 JPH0344276B2 JP58154112A JP15411283A JPH0344276B2 JP H0344276 B2 JPH0344276 B2 JP H0344276B2 JP 58154112 A JP58154112 A JP 58154112A JP 15411283 A JP15411283 A JP 15411283A JP H0344276 B2 JPH0344276 B2 JP H0344276B2
- Authority
- JP
- Japan
- Prior art keywords
- fuel
- hollow
- pellets
- fuel rod
- fuel pellets
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 239000000446 fuel Substances 0.000 claims description 67
- 239000008188 pellet Substances 0.000 claims description 39
- JFALSRSLKYAFGM-UHFFFAOYSA-N uranium(0) Chemical compound [U] JFALSRSLKYAFGM-UHFFFAOYSA-N 0.000 claims description 7
- 229910052770 Uranium Inorganic materials 0.000 claims description 4
- 238000005253 cladding Methods 0.000 claims description 4
- 230000000694 effects Effects 0.000 description 5
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 230000004992 fission Effects 0.000 description 1
- 239000011796 hollow space material Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000004449 solid propellant Substances 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E30/00—Energy generation of nuclear origin
- Y02E30/30—Nuclear fission reactors
Landscapes
- Monitoring And Testing Of Nuclear Reactors (AREA)
- Glass Compositions (AREA)
Description
【発明の詳細な説明】
〔発明の技術分野〕
本発明はブランケツト部とガスプレナム部とを
改良した燃料棒に関する。TECHNICAL FIELD OF THE INVENTION The present invention relates to a fuel rod with an improved blanket section and gas plenum section.
従来の中実燃料ペレツトのみからなる燃料要素
において、その燃料棒の頂部には、燃料ペレツト
から出る気体の核分裂生成物（以下F.Pガスと略
称す）によつて過度に内圧が上昇しないようにプ
レナム室と称する空室が設けられている。このプ
レナム室の容積は、燃料有効長の10〜15％の相当
する部分の空室容積を必要とされている。
In conventional fuel elements consisting only of solid fuel pellets, a plenum is installed at the top of the fuel rod to prevent the internal pressure from rising excessively due to gaseous fission products (hereinafter abbreviated as FP gas) released from the fuel pellets. There are empty rooms called rooms. The volume of this plenum chamber is required to be equivalent to 10 to 15% of the effective length of the fuel.
一方、燃料の有効利用を計るために、最近は燃
料有効長の中央部を高濃縮度化し、その分だけ軸
方向の両端を低濃縮している。しかし、このため
に燃料要素の軸方向の中性子分布は、中央部にお
いてピーキング係数が大きくなる。これを改善す
るために、燃料要素を長くしないで、プレナム部
を小さくして燃料有効長を大きくすることによ
り、ピーキングを小さくすることができる。しか
し、これではプレナム部の容積減少によつて燃料
要素内のF.Pガス圧が高まる結果となる。 On the other hand, in order to make more effective use of fuel, recently the center of the effective fuel length has been made highly enriched, and both axial ends have been made less enriched. However, for this reason, the neutron distribution in the axial direction of the fuel element has a large peaking coefficient at the center. To improve this, the peaking can be reduced by making the plenum smaller and increasing the effective fuel length without making the fuel element longer. However, this results in an increase in the FP gas pressure within the fuel element due to the reduced volume of the plenum.
本発明の目的は、燃料有効長の確保とプレナム
室の必要容積を確保した燃料棒を提供するにあ
る。
An object of the present invention is to provide a fuel rod that secures the effective fuel length and the required volume of the plenum chamber.
本発明による燃料棒は、密封された被覆管内に
積み重ねて充填した複数の燃料ペレツトの積重方
向における中央部付近を比較的高い濃縮度の燃料
ペレツトで構成し、その両端部付近を低濃縮度の
中空燃料ペレツトで構成したことを特徴とするも
のである。
The fuel rod according to the present invention consists of a plurality of fuel pellets stacked and filled in a sealed cladding tube, and the central part in the stacking direction is made up of relatively high enrichment fuel pellets, and the end parts are made up of low enrichment fuel pellets. It is characterized by being composed of hollow fuel pellets.
以下本発明を図面に示す実施例について説明す
る。図面において本発明による燃料棒１は、被覆
管２内に燃料ペレツト３，４を積み上げ、その頂
部にガスプレナム室５を形成し、これをプレナム
スプリング６を介して端栓７，８により密封して
構成されている。
The present invention will be described below with reference to embodiments shown in the drawings. In the drawing, a fuel rod 1 according to the present invention has fuel pellets 3 and 4 piled up in a cladding tube 2 and a gas plenum chamber 5 formed at the top thereof, which is sealed by end plugs 7 and 8 via a plenum spring 6. It is configured.
本発明においては、燃料要素１の軸方向の中央
部付近に濃縮度の高い（３〜5w％濃縮度）燃料
ペレツト３を積み上げ、その両端の燃料ペレツト
４，４は天然ウラン又は劣化ウランの中空ペレツ
トを使用している。そして燃料ペレツト４，４の
中空部９，９の径はペレツト外径の約50％程度に
設定している。 In the present invention, highly enriched fuel pellets 3 (3 to 5 w% enrichment) are piled up near the center in the axial direction of the fuel element 1, and the fuel pellets 4 at both ends are hollow spaces made of natural uranium or depleted uranium. It uses pellets. The diameter of the hollow portions 9, 9 of the fuel pellets 4, 4 is set to approximately 50% of the outer diameter of the pellets.
この燃料棒１の燃料有効長の両端にある中空燃
料ペレツト４，４の部分をブランケツト領域にす
ると、中央部の燃料ペレツト３，３の出力が大き
くなつてピーキング係数が増大する。しかしピー
キング係数の増大は、約10％位まで許容されるか
ら、中空燃料ペレツト４，４のブランケツト領域
としては、中性子リークを少なくするのに十分な
長さである燃料有効長の10〜20％程度が適当であ
る。また中空燃料ペレツト４，４の中空径９，９
は製造技術にもよるが、中空径が余り大きいとプ
レスの歩留りが低下する点と、実質的なペレツト
密度の低下によるブランケツト燃料としての出力
密度の不足の点から、ペレツト密度で約75％に相
当する約50％程度がよい。 When the hollow fuel pellets 4, 4 at both ends of the effective fuel length of the fuel rod 1 are made into blanket regions, the output of the fuel pellets 3, 3 in the central portion increases, and the peaking coefficient increases. However, since the increase in the peaking coefficient is allowed up to about 10%, the blanket region of the hollow fuel pellets 4, 4 should be 10 to 20% of the effective length of the fuel, which is long enough to reduce neutron leakage. The degree is appropriate. Also, the hollow diameters of the hollow fuel pellets 4 and 4 are 9 and 9.
Although it depends on the manufacturing technology, if the hollow diameter is too large, the press yield will decrease, and the pellet density will be insufficient as a blanket fuel due to a substantial decrease in pellet density, so the pellet density should be about 75%. A value of about 50% is good.
このように本発明による燃料棒１においては、
積重ねた燃料ペレツトのブランケツト部に中空燃
料ペレツト４，４を使用することにより、ブラン
ケツト効果を保持するとともに、その中空部９，
９をガスプレナム室５の一部とすることができ
る。また、中空燃料ペレツト４，４は、低濃縮度
のものを中空にしているため、燃焼度の推移によ
るＫ∞の減少過程において、中空化による核分裂
物質の絶対値の減少による効果は小さい。さらに
ブランケツト部からのF.Pガス量は小さい、逆に
ブランケツト部を中空燃料ペレツトにすることで
ガスプレナム部５を小さくして燃料要素の全長を
その分だけ短くすることができる。 In this way, in the fuel rod 1 according to the present invention,
By using the hollow fuel pellets 4, 4 in the blanket part of the stacked fuel pellets, the blanket effect is maintained and the hollow part 9,
9 may be part of the gas plenum chamber 5. Furthermore, since the hollow fuel pellets 4, 4 are hollow ones with low enrichment, the effect of reducing the absolute value of fissile material due to hollowing out is small in the process of decreasing K∞ due to changes in burnup. Furthermore, the amount of FP gas from the blanket section is small; conversely, by making the blanket section a hollow fuel pellet, the gas plenum section 5 can be made smaller and the overall length of the fuel element can be shortened accordingly.
例えば、燃料有効長3708mmの燃料要素は、約
370mmのガスプレナムを有している。こゝで本発
明において燃料有効長の13％を中央率25％のペレ
ツトとする。全長平均で3.9w％濃縮度の燃料棒
で、その長さの13％の部分を中空率25％の天然ウ
ランペレツト４とすると、中央部の燃料ペレツト
３は、濃縮度4.4w％となる。そしてこの部分の
出力は、約10％増大することと、燃焼度が約20％
増加することによりF.Pガス放出量として約30％
増加する。これに対し、中空燃料ペレツト４，４
は、出力の低下、燃焼度の低下、中空によるF.P
放出率の低下の効果で、中実ペレツトの場合の20
％程度の放出量となる。この結果、プレナム室５
の長さは約65mm短かい305mmにすることができる。
また燃料棒１の両端が発熱の小さいブランケツト
部であるので、サーマルウエアを省略することが
できる効果もある。これらの効果によりもし燃料
有効長を大きくするとすれば、燃料有効長を燃料
棒の全長を同じに保つて約80mm程度大きくするこ
とができる。 For example, a fuel element with an effective fuel length of 3708 mm is approximately
It has a 370mm gas plenum. Therefore, in the present invention, 13% of the effective fuel length is made up of pellets with a median ratio of 25%. If a fuel rod has an average enrichment of 3.9w% over its entire length, and 13% of its length is made of natural uranium pellets 4 with a hollow content of 25%, the fuel pellets 3 in the center have an enrichment of 4.4w%. The output of this part will increase by about 10% and the burnup will increase by about 20%.
Approximately 30% of FP gas emission due to increase
To increase. On the other hand, hollow fuel pellets 4,4
is a decrease in power output, decrease in burnup, and FP due to hollow space.
20 for solid pellets due to the effect of lower release rate.
The amount released is approximately %. As a result, plenum room 5
The length can be about 65mm shorter to 305mm.
Furthermore, since both ends of the fuel rod 1 are blanket portions that generate less heat, there is an advantage that thermal wear can be omitted. Due to these effects, if the effective fuel length is to be increased, the effective fuel length can be increased by about 80 mm while keeping the overall length of the fuel rod the same.
以上のように本発明によれば、積重ねられた燃
料ペレツトの中央部を比較的高い濃縮度の燃料ペ
レツトで構成し、その両端部分を天然ウラン又は
劣化ウランを用いた低濃縮度の中空燃料ペレツト
で構成したことにより、燃料の利用効率が向上さ
れ、かつ中空燃料ペレツトの中空部のガスプレナ
ム部への利用によつてＦ・Ｐガスの収容領域を確
保することができる。
As described above, according to the present invention, the central part of the stacked fuel pellets is made up of fuel pellets with relatively high enrichment, and both end parts are made up of hollow fuel pellets with low enrichment using natural uranium or depleted uranium. With this configuration, the fuel utilization efficiency is improved, and the storage area for F/P gas can be secured by using the hollow part of the hollow fuel pellet in the gas plenum part.
図面は本発明による燃料棒の一実施例を示す断
面図である。
１……燃料棒、２……被覆管、３……燃料ペレ
ツト、４……中空燃料ペレツト、５……ガスプレ
ナム室、６……プレナムスプリング、７，８……
端栓、９……中空部。
The drawing is a sectional view showing one embodiment of a fuel rod according to the present invention. 1... Fuel rod, 2... Cladding tube, 3... Fuel pellet, 4... Hollow fuel pellet, 5... Gas plenum chamber, 6... Plenum spring, 7, 8...
End plug, 9...Hollow part.
Claims (1)
て複数の燃料ペレツトを積重ねて充填した燃料棒
において、その積重ねられた燃料ペレツトの積重
方向における中央部付近を比較的高い濃縮度の燃
料ペレツトで構成し、その両端部付近を天然ウラ
ンまたは劣化ウランの低濃縮度の中空燃料ペレツ
トで構成したことを特徴とする燃料棒。 ２ 中空燃料ペレツトの中空部容積とガスプレナ
ム室の容積との総計が燃料棒の有効部分の容積の
10〜20％になるように設定したことを特徴とする
特許請求の範囲第１項記載の燃料棒。[Claims] 1. In a fuel rod in which a plurality of fuel pellets are stacked and filled in a sealed cladding tube excluding the gas plenum chamber, the fuel pellets are relatively highly concentrated near the center in the stacking direction of the stacked fuel pellets. What is claimed is: 1. A fuel rod comprising hollow fuel pellets of low enrichment of natural uranium or depleted uranium near both ends thereof. 2 The total volume of the hollow part of the hollow fuel pellet and the volume of the gas plenum chamber is the volume of the effective part of the fuel rod.
The fuel rod according to claim 1, wherein the fuel rod is set to 10 to 20%.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58154112A JPS6046485A (en) | 1983-08-25 | 1983-08-25 | Fuel rod |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58154112A JPS6046485A (en) | 1983-08-25 | 1983-08-25 | Fuel rod |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6046485A JPS6046485A (en) | 1985-03-13 |
| JPH0344276B2 true JPH0344276B2 (en) | 1991-07-05 |
Family
ID=15577184
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP58154112A Granted JPS6046485A (en) | 1983-08-25 | 1983-08-25 | Fuel rod |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6046485A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04304805A (en) * | 1991-04-03 | 1992-10-28 | Sliontec:Kk | Production of seeding sheet |
| JPH06342090A (en) * | 1993-05-28 | 1994-12-13 | Nuclear Fuel Ind Ltd | Fuel rod |
-
1983
- 1983-08-25 JP JP58154112A patent/JPS6046485A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6046485A (en) | 1985-03-13 |
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