201023206 六、發明說明： 【發明所屬之技術領域】 本發明有關核反應器燃料整件用之分隔柵，一冷卻劑 液體將通過該分隔柵，該分隔栅之型式界定複數單元，用 於容納在一縱向中延伸之燃料棒，該柵包括用於混合該冷 卻劑液體流之葉片。 本發明係特別可適用於輕水反應器（LWR )，不論它 ❹ 們是否爲加壓水反應器（PWR)或沸水反應器（BWR)。 【先前技術】 在用於加壓水核反應器之燃料整件中，該等燃料棒係 藉由一構架固持在適當位置中，該構架大致上包括藉由諸 如導引管的修長元件所接合之二端部配件、及數個分隔柵 。該等柵係沿著該等導引管分佈，且形成用於固持該燃料 棒之單元，該等燃料棒被配置於一整齊的之網路中及被保 • 持彼此隔開。 —旦該等整件被放置於一核反應器之核心中，它們被 水所垂直地橫越，其中該等燃料棒被浸入，以便冷卻它們 〇 其想要的是防止在該等燃料棒之護套上顯現熱點。這 是因爲使得熱點能促進局部沸騰發生，這能導致該護套破 裂。爲防止此等熱點顯現，該等柵被設計成可於冷卻劑液 體流中建立亂流。這些亂流係藉由混合葉片所建立，該等 葉片使水流均勻化，且藉由造成該冷卻劑水在該等整件內 -5- 201023206 之橫亙再分配減少該等護套上之不同點間之溫度中的差異 。這些葉片被提供接近藉由該等柵所形成的單元之角落， 且被彎曲越過冷卻劑水流。 譬如，專利文件ΕΡ-0 1 8 1 264敘述此等混合葉片。 於使用中，該等燃料棒之壁面藉由強制對流傳熱至該 冷卻劑水。於該燃料整件之最熱部份中，該等燃料棒護套 之溫度係高於該飽和溫度，且小蒸氣氣泡形成在該等護套 的外部壁面上，及接著與該冷卻劑水分離及藉由該冷卻劑 _ 水帶送離開。在這些區域中熱係藉由成核沸騰所傳送，且 此熱傳系統之效率能夠使該壁面之溫度穩定的。然而，於 核反應器之某些操作條件中，儘管該等混合葉片之存在， 該等氣泡可變得極多、聚結及開始一沸騰臨界。該等反應 器之操作參數被界定，以致任何沸騰臨界能被避免。既然 其對應於成核沸騰之系統的末端，此用於背離成核沸騰之 沸騰臨界現象、大致上稱爲DNB，以減少該燃料棒及該冷 卻劑水間之熱傳送，且能在該燃料棒之護套上導致一層蒸 〇 氣之出現’這幾乎完全地停止來自藉由抽空該冷卻劑水之 熱，且如此可經由其溫度中之過度的上昇對該護套導致損 壞。 【發明內容】 本發明針對藉由提供一分隔柵改善該燃料整件之溫度 液壓效率’該分隔柵遲延一沸騰臨界顯現之風險。 爲該目的’本發明有關上述型式之分隔柵，其中至少 * 6 - 201023206 一混合葉片具有至少一面，該面設有複數凹凸不平部份。 該葉片的表面上之凹凸不平部份允許冷卻劑液體流甚 至更爲分裂，這防止穩定的系統變得被建立於此流動中， 且如此遲延背離成核沸騰之現象的發展。該申請人注意到 在冷卻劑液體流中之穩定系統的建立將促進背離成核沸騰 之現象。 該等燃料棒及該冷卻劑液體間之熱傳送如此被改善， φ 該燃料整件之效率被最佳化，且對該等燃料棒的損壞之風 險係減少。 根據該分隔柵之其他選擇性態樣： -該複數凹凸不平部份被配置在一大致整齊的網路中 t -該複數凹凸不平部份包括延伸經過該葉片之開口； -該等開口包括圓形孔洞； -該等孔洞之直徑係大約在由〇·1毫米至0.8毫米之範 Φ 圍內； -該等開口包括狹縫； -該等狹縫之寬度係大約在由0.1毫米至0.8毫米之範 圍內； -該葉片具有至少十個凹凸不平部份； -具有複數凹凸不平部份之葉片的該面係面朝冷卻劑 液體流的面；及 -藉由該柵所界定之至少一單元包括用於固持一燃料 棒之機構。 201023206 本發明亦有關一核反應器燃料整件，其包括一構架及 一組藉由該構架所固持之燃料棒’其中該構架包括至少一 如上面所述之分隔柵。 【實施方式】 於該敘述中，當該燃料整件係處於核反應器之核心時 ，該“縱向”一詞被界定爲該冷卻劑液體流E之方向、亦 即一大約直立之方向。該“橫亙”被界定爲一大約垂直於 @ 該縱向之方向。 圖1顯示一加壓水核反應器用之燃料整件1。 通常，該燃料整件1包括一構架2及一組4藉由該構 架2所固持之燃料棒6。該等燃料棒6係彼此隔開及被配 置在一整齊的網路中。該構架2包括藉由諸如導引管12 的修長元件所接合之下端件8及上端件10，該等修長元件 大約沿著該整件1之縱向L直立地延伸。該構架2包括複 數沿著該等導引管12分佈及固定至該等導引管之分隔柵 ❹ 14。通常，該等分隔柵14固持該等燃料棒6。 每一燃料棒6包括設置在形成該棒6的外部表面之護 套中的一堆核子燃料（未示出）之彈九。此等燃料棒係已 知，且將不被任何更詳細地敘述。 爲了當該燃料整件係處於一核反應器核心中時冷卻該 燃料整件1，一冷卻劑流體、在此案例中爲水將於該整件 中在一大約直立之方向中、由該下端件8循環朝向該上端 件1 0，如藉由圖1中之箭頭E所指示。 -8 - 201023206 通常，以此一便於界定單元22之方式，每一柵14包 括大約彼此垂直地延伸及在相交點20交叉之二組交叉板 件16及1 8，如圖2所示。 該等單元22容納該等燃料棒6及該等導引管12。 該等板件16及18係譬如通常由锆基合金所製成，且 經由刻槽組裝及在其相交點20被焊接至彼此。 每一單元22包括用於固持該等燃料棒6之機構。這 φ 些固持機構譬如係藉由意欲支承抵靠著該等燃料棒6之突 出部份24及彈簧26與28 (圖3 )所形成。 該分隔柵14包括接近至少部份該等相交點20之混合 葉片30。這些葉片30大致上由該等板件16及18之上緣 延伸’且係相對於這些板件橫亙地傾斜朝向該等單元22 之內部’以致它們係位於該冷卻劑液體流E之路徑中。如 此，該冷卻劑液體係藉由該等葉片30轉向該等燃料棒6， 這能夠使該冷卻劑液體有一橫亙之再分配及此液體在該等 # 燃料棒6上方之均勻分佈。 該等葉片3 〇譬如係藉由切開活葉之簡單折疊所製成 ’並與該寺板件16及18爲一體的。 葉片30之配置及數目能根據認爲該冷卻劑液體之分 佈的均句化、及避免增加此等葉片所造成的冷卻劑液體中 之壓力損失的需要之相對重要性而變化。如此，葉片30 之數目越大，則該液體之分佈更均勻，但該冷卻劑液體中 之壓力的損失越大。 該專利文件ΕΡ-0 1 8 1 264敘述葉片之數個分隔柵組構 201023206 及配置。吾人能譬如參考此文件，以便選擇該等葉片30 之位置。 參考圖4及5，現在隨後有根據本發明的葉片30之更 詳細敘述。 該葉片30在至少其下面、亦即面朝該流動E之該面 上包括凹凸不平部份32之網路。凹凸不平部份意指該等 葉片30之下面的一局部修改，諸如一間斷點或形貌特徵 (突出部份或中空部份）之形成，反之該先前技藝之葉片 魏 具有平滑及連續之面。這些凹凸不平部份32分裂藉由該 葉片30所轉向之冷卻劑液體流E，且如此在此流動E中 限制一穩定系統之建立。 一穩定系統之建立將促進DNB現象之發生。這是因 爲當有一穩定系統時，藉由該等燃料棒6及該冷卻劑液體 間之熱傳送所建立、且形成在該等燃料棒6之護套的壁面 上之蒸氣的氣泡未總是被有效率地帶離。該等氣泡於累積 中形成較大之氣泡，其最後可在該護套上形成一層蒸氣， @ 並能導致散熱被完全地停止。 藉由分裂被該等葉片30所轉向之流動，該冷卻劑液 體流中之亂流係增加，能夠使該等氣泡形成在該護套上， 以被更有效率地抽空。該等凹凸不平部份32如此使得其 可能遲延DNB之發生，並改善該等燃料棒6及該冷卻劑 液體間之熱傳送，其改善該燃料整件1之效率，且能夠更 安全地管理該反應器，在DNB的發生之前具有一較大之 餘裕，其係該反應器之操作的一限制因素。 -10- 201023206 根據圖4及5所示之具體實施例，該等凹凸不平部份 32係由其下面至其上面延伸經過該葉片30之開口。當該 流動E的一部份通過該開口時，藉由該葉片30所轉向之 流動E被分裂。 該等開口係以此一便於形成凹凸不平部份32之網路 的方式分佈越過該整個葉片30。這些開口係特別簡單藉由 該葉片30之穿孔所製成。 φ 根據圖4所示具體實施例，該等開口係大約圓形之孔 洞，其直徑之範圍譬如由0.1毫米至0.8毫米。這些尺寸 大約對應於該等燃料棒之護套的壁面上所形成之氣泡的大 小，且允許大量凹凸不平部份32被設置在每一葉片30上 方。如此，凹凸不平部份32之數目係譬如大於或等於10 ，這允許該流動以很令人滿意之方式分裂。 根據圖5所示之具體實施例，該等開口係橫亙之狹縫 ，其寬度1係譬如在大約由0.1毫米至〇.8毫米之範圍內 • 。該等狹縫大約係直線組成的、彼此平行，且被分佈在該 葉片30之高度上方。 其他形式之凹凸不平部份可被預見的，諸如形成在該 葉片30之下面的至少該表面上及轉向該液體流E之突出 部份或中空部份，雖然該等凹凸不平部份32較佳地是延 伸經過該葉片3 0之開口。 凹凸不平部份32之數個不同形式能被使用在該等葉 片30上或甚至在該相同之葉片30上。該等凹凸不平部份 32可被隨意地設置或設置於一多少整齊的網路中，如在圖 -11 - 201023206 4及5中所示。 本發明之數個係可能的，且其係適用於以大變化性之 方式所形成的柵。特別地是，本發明能被使用於柵，其各 單元係藉由固定至彼此之軸套所形成，以便形成諸單元之 網路。其他柵之形式亦可被預見的。 —分隔柵14之僅只部份葉片30可具有上述結構。 同樣地’本發明可被僅只應用至燃料整件1中之一個 或一些分隔柵14。 本發明已參考一加壓水反應器用之燃料整件敘述，其 係特別有利的，以便經過氣泡及典型在加壓水反應器之 DNB的密集形成減少一沸騰臨界之風險。其係亦適用於沸 水反應器用燃料整件中之分隔柵，以便改善該等燃料棒與 該冷卻劑液體間之熱傳送，以便藉由典型在沸水反應器之 乾燥（已知爲變乾）經過臨界加熱減少一沸騰臨界之風險 ❹ 【圖式簡單說明】 本發明之其他態樣及優點將於該敘述之過程中變得明 顯，該敘述隨後被給與當作一範例並參考所附圖面，其中 -圖1係根據本發明之燃料整件的一圖解， -圖2係一由圖1中之整件中的分隔栅上面之槪要視 圖， -圖3係沿著圖2中之剖線III-III的橫截面圖解， -12- 201023206 -圖4係圖2及3中之混合栅中的混合葉片之側視圖 -圖5根據本發明之另一具體實施例的混合葉片之側 視圖。 【主要元件符號說明】 1 :燃料整件 2 ·構架 4 :組 6 :燃料棒 8 :下端件 1 〇 :上端件 12 :導引管 1 4 :分隔柵 1 6 :板件 φ 1 8 :板件 20 :相交點 22 :單元 24 :突出部份 2 6 :彈簧 2 8 :彈簧 30 :葉片 3 2 :凹凸不平部份 -13-201023206 VI. Description of the Invention: [Technical Field] The present invention relates to a separator for a nuclear reactor fuel whole body, through which a coolant liquid will pass, the type of the dividing grid defining a plurality of units for housing in a A fuel rod extending longitudinally, the grid including blades for mixing the coolant liquid stream. The invention is particularly applicable to light water reactors (LWR), whether or not they are pressurized water reactors (PWR) or boiling water reactors (BWR). [Prior Art] In a fuel monolith for a pressurized water nuclear reactor, the fuel rods are held in position by a frame, the frame substantially comprising being joined by a slender element such as a guide tube Two end fittings and several dividing grids. The grids are distributed along the guide tubes and form means for holding the fuel rods, the fuel rods being disposed in a neat network and spaced apart from each other. Once the monoliths are placed in the core of a nuclear reactor, they are vertically traversed by water, wherein the fuel rods are immersed in order to cool them, and what they want is to prevent protection of the fuel rods. Set up a hot spot. This is because the hot spot promotes local boiling, which can cause the sheath to break. To prevent such hot spots from appearing, the grids are designed to create turbulent flow in the coolant liquid stream. These turbulences are established by mixing blades that homogenize the water flow and reduce the difference in the jackets by causing the coolant water to redistribute across the entire -5 - 201023206 The difference between the temperatures. The vanes are provided proximate to the corners of the cells formed by the grids and are bent past the coolant water stream. For example, the patent document ΕΡ-0 1 8 1 264 describes such hybrid blades. In use, the walls of the fuel rods are forced to convectively transfer heat to the coolant water. In the hottest portion of the fuel assembly, the temperature of the fuel rod sheath is higher than the saturation temperature, and small vapor bubbles are formed on the outer wall of the jacket, and then separated from the coolant water. And sent away by the coolant _ water belt. In these regions the heat is transferred by nucleation boiling and the efficiency of the heat transfer system stabilizes the temperature of the wall. However, in certain operating conditions of the nuclear reactor, the bubbles may become extremely numerous, coalesced, and begin a boiling threshold despite the presence of the mixing blades. The operating parameters of the reactors are defined such that any boiling criticality can be avoided. Since it corresponds to the end of the nucleate boiling system, this boiling critical phenomenon for deviating from nucleate boiling, generally referred to as DNB, reduces the heat transfer between the fuel rod and the coolant water, and can be used in the fuel The appearance of a layer of steam enthalpy on the sheath of the rod 'this almost completely stops the heat from evacuating the coolant water, and thus can cause damage to the sheath via an excessive rise in its temperature. SUMMARY OF THE INVENTION The present invention is directed to improving the temperature hydraulic efficiency of the fuel assembly by providing a dividing grid. The risk of the grid delaying a boiling critical manifestation. For this purpose, the present invention relates to a dividing grid of the above type, wherein at least *6 - 201023206 a mixing blade has at least one side, the face being provided with a plurality of uneven portions. The uneven portion on the surface of the blade allows the coolant liquid to flow even more, which prevents a stable system from becoming established in the flow, and thus delays the development of the phenomenon of nucleate boiling. The Applicant has noted that the establishment of a stable system in the coolant liquid stream will promote the phenomenon of deviation from nucleate boiling. The heat transfer between the fuel rods and the coolant liquid is thus improved, φ the efficiency of the fuel unit is optimized, and the risk of damage to the fuel rods is reduced. According to other alternative aspects of the dividing grid: - the plurality of rugged portions are arranged in a substantially neat network t - the plurality of rugged portions comprising openings extending through the vanes; - the openings comprising a circle Shaped holes; - the diameter of the holes is approximately in the range of 〇1 mm to 0.8 mm; - the openings include slits; - the width of the slits is approximately 0.1 mm to 0.8 mm Within the range; - the blade has at least ten rugged portions; - the face of the blade having a plurality of rugged portions facing the surface of the coolant liquid flow; and - at least one unit defined by the grid Includes mechanisms for holding a fuel rod. 201023206 The invention also relates to a nuclear reactor fuel assembly comprising a frame and a plurality of fuel rods held by the frame, wherein the frame comprises at least one dividing grid as described above. [Embodiment] In this description, when the fuel unit is at the core of the nuclear reactor, the term "longitudinal" is defined as the direction of the coolant liquid stream E, that is, an approximately upright direction. The "cross" is defined as a direction approximately perpendicular to the longitudinal direction of @. Figure 1 shows a fuel unit 1 for a pressurized water nuclear reactor. Typically, the fuel unit 1 includes a frame 2 and a set of 4 fuel rods 6 held by the frame 2. The fuel rods 6 are spaced apart from each other and are arranged in a neat network. The frame 2 includes an end piece 8 and an upper end piece 10 joined by a slender element such as a guide tube 12 that extends upright about the longitudinal direction L of the unitary piece 1. The frame 2 includes a plurality of dividing grids 14 distributed along the guiding tubes 12 and secured to the guiding tubes. Typically, the dividers 14 hold the fuel rods 6. Each fuel rod 6 includes a stack of nuclear fuel (not shown) disposed in a jacket forming the outer surface of the rod 6. These fuel rods are known and will not be described in any detail. In order to cool the fuel unit 1 when the fuel unit is in the core of a nuclear reactor, a coolant fluid, in this case water, will be in the approximately upright direction of the unit, from the lower end piece 8 is directed toward the upper end member 10 as indicated by arrow E in FIG. -8 - 201023206 Generally, in a manner that facilitates the definition of the unit 22, each of the grids 14 includes two sets of intersecting plates 16 and 18 that extend approximately perpendicular to each other and intersect at an intersection point 20, as shown in FIG. The units 22 house the fuel rods 6 and the guide tubes 12. The plates 16 and 18 are, for example, typically made of a zirconium-based alloy and assembled via the grooves and welded to each other at their intersections 20. Each unit 22 includes a mechanism for holding the fuel rods 6. These retaining mechanisms are formed, for example, by the projections 24 and springs 26 and 28 (Fig. 3) intended to be supported against the fuel rods 6. The dividing grid 14 includes mixing vanes 30 adjacent at least a portion of the intersecting points 20. These vanes 30 extend substantially from the upper edges of the panels 16 and 18 and are inclined transversely relative to the panels toward the interior of the units 22 such that they are in the path of the coolant liquid stream E. Thus, the coolant liquid system is deflected by the vanes 30 to the fuel rods 6, which enables a redistribution of the coolant liquid and a uniform distribution of the liquid over the #fuel rods 6. The blades 3 are made, for example, by simple folding of the cutting leaves and are integral with the temple panels 16 and 18. The configuration and number of vanes 30 can vary depending on the relative importance of the uniformity of the distribution of the coolant liquid and the need to avoid increasing the pressure loss in the coolant liquid caused by such vanes. Thus, the greater the number of vanes 30, the more uniform the distribution of the liquid, but the greater the loss of pressure in the coolant liquid. This patent document ΕΡ-0 1 8 1 264 describes several partition grids 201023206 and configurations of the blades. We can refer to this document as such to select the location of the blades 30. Referring to Figures 4 and 5, there is now a more detailed description of the blade 30 in accordance with the present invention. The blade 30 includes a network of rugged portions 32 at least underneath, i.e., facing the surface of the flow E. The rugged portion means a partial modification of the underside of the vanes 30, such as the formation of a breakpoint or topographical feature (protrusion or hollow portion), whereas the prior art blade has a smooth and continuous surface. . These rugged portions 32 split the coolant liquid flow E steered by the vanes 30, and thus restrict the establishment of a stabilizing system in this flow E. The establishment of a stable system will promote the occurrence of the DNB phenomenon. This is because when there is a stabilizing system, the bubbles established by the heat transfer between the fuel rods 6 and the coolant liquid and which form the vapor on the wall of the sheath of the fuel rods 6 are not always Efficiently separated. These bubbles form a larger bubble in the accumulation which eventually forms a layer of vapor on the sheath, @ which causes the heat to be completely stopped. By splitting the flow steered by the vanes 30, the turbulent flow in the coolant liquid flow is increased, enabling the bubbles to be formed on the jacket to be evacuated more efficiently. The uneven portions 32 are such that they may delay the occurrence of DNB and improve the heat transfer between the fuel rods 6 and the coolant liquid, which improves the efficiency of the fuel unit 1 and enables safer management of the The reactor has a large margin before the ODN occurs, which is a limiting factor in the operation of the reactor. -10-201023206 According to the embodiment shown in Figures 4 and 5, the uneven portions 32 extend from the underside to the opening of the blade 30 therethrough. When a portion of the flow E passes through the opening, the flow E deflected by the vane 30 is split. The openings are distributed across the entire blade 30 in a manner that facilitates the formation of a network of rugged portions 32. These openings are particularly simple by the perforation of the blade 30. φ According to the embodiment shown in Fig. 4, the openings are approximately circular holes having a diameter ranging from 0.1 mm to 0.8 mm. These dimensions approximately correspond to the size of the bubbles formed on the wall of the sheath of the fuel rods, and allow a large number of uneven portions 32 to be placed above each of the vanes 30. Thus, the number of the uneven portions 32 is, for example, greater than or equal to 10, which allows the flow to be split in a satisfactory manner. According to the embodiment shown in Figure 5, the openings are transverse slits having a width 1 such as in the range of from about 0.1 mm to about 0.8 mm. The slits are approximately linearly parallel to each other and are distributed above the height of the blade 30. Other forms of rugged portions may be foreseen, such as at least on the surface of the underside of the blade 30 and toward the protruding portion or hollow portion of the liquid stream E, although the uneven portions 32 are preferred. The ground is an opening that extends through the blade 30. Several different forms of the uneven portion 32 can be used on the vanes 30 or even on the same vane 30. The uneven portions 32 can be arbitrarily set or placed in a neat network, as shown in Figures -11 - 201023206 4 and 5. Several of the present invention are possible and are suitable for use in gates formed in a highly variable manner. In particular, the invention can be used in a grid, the cells of which are formed by bushings that are secured to each other to form a network of cells. Other grid forms can also be foreseen. - Only a portion of the blades 30 of the dividing grid 14 may have the above structure. Similarly, the present invention can be applied only to one or some of the partitions 14 of the fuel unit 1. The present invention has been described with reference to a fuel unit for a pressurized water reactor which is particularly advantageous for reducing the risk of a boiling threshold through the intensive formation of bubbles and DNB typically in a pressurized water reactor. It is also applicable to the dividing grid in the whole fuel of the boiling water reactor in order to improve the heat transfer between the fuel rods and the coolant liquid, so as to pass through the drying (known as drying) which is typically carried out in a boiling water reactor. Critical heating reduces the risk of a boiling threshold ❹ [Simplified description of the drawings] Other aspects and advantages of the present invention will become apparent in the course of the description, which is subsequently referred to as an example and reference to the drawings. 1 is a schematic view of a fuel unit according to the present invention, - FIG. 2 is a schematic view of the upper part of the partition in the whole of FIG. 1, and FIG. 3 is a section along the line of FIG. Cross-sectional illustration of line III-III, -12-201023206 - Figure 4 is a side view of a mixing blade in the mixing grid of Figures 2 and 3 - Figure 5 side view of a mixing blade in accordance with another embodiment of the present invention . [Explanation of main component symbols] 1 : Fuel whole part 2 · Frame 4 : Group 6 : Fuel rod 8 : Lower end piece 1 〇: Upper end piece 12 : Guide tube 1 4 : Partition grid 1 6 : Plate piece φ 1 8 : Plate Item 20: Intersection point 22: Unit 24: Projection part 2 6 : Spring 2 8 : Spring 30 : Blade 3 2 : Rugged section - 13 -