CA1104729A - Apparatus for improving critical power ratio in a nuclear fuel bundle - Google Patents
Apparatus for improving critical power ratio in a nuclear fuel bundleInfo
- Publication number
- CA1104729A CA1104729A CA306,420A CA306420A CA1104729A CA 1104729 A CA1104729 A CA 1104729A CA 306420 A CA306420 A CA 306420A CA 1104729 A CA1104729 A CA 1104729A
- Authority
- CA
- Canada
- Prior art keywords
- bundle
- fuel
- fuel bundle
- nuclear fuel
- flow
- 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
Links
Classifications
-
- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21C—NUCLEAR REACTORS
- G21C3/00—Reactor fuel elements and their assemblies; Selection of substances for use as reactor fuel elements
- G21C3/30—Assemblies of a number of fuel elements in the form of a rigid unit
- G21C3/32—Bundles of parallel pin-, rod-, or tube-shaped fuel elements
- G21C3/322—Means to influence the coolant flow through or around the bundles
-
- 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
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Plasma & Fusion (AREA)
- General Engineering & Computer Science (AREA)
- High Energy & Nuclear Physics (AREA)
- Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A flow splitter apparatus positioned within a nuclear fuel bundle sectionalizes the bundle into a number of compart-ments and provides an unheated surface along which liquid coolant flows. The splitter apparatus has a length equal to that of a fuel bundle, extends from the interior of the fuel bundle to the wall of the nuclear reactor channel and or from this wall to the inner portion of the bundle and competes with this wall for liquid coolant. The flow splitter apparatus reduces the amount of steam-water stratification occurring in the bundle.
A flow splitter apparatus positioned within a nuclear fuel bundle sectionalizes the bundle into a number of compart-ments and provides an unheated surface along which liquid coolant flows. The splitter apparatus has a length equal to that of a fuel bundle, extends from the interior of the fuel bundle to the wall of the nuclear reactor channel and or from this wall to the inner portion of the bundle and competes with this wall for liquid coolant. The flow splitter apparatus reduces the amount of steam-water stratification occurring in the bundle.
Description
BACKGROUND OF THE INVENTION
This invention relates to a nuclear ~uel bundle for a nuclear reactor having a flow splitter apparatus. The splitter apparatus provides unheated surfaces along which liquid coolant flows through the interior of the fuel bundle.
A fuel bundle that is commonly used consists of an array of fuel rods having a longitudinal axis positioned within a channel of a nuclear reactor on a horizontal plane. Coolant passing through the ~uel bundle usually enters a two pha~e regime, ~or example, steam and water. Water has a tendency to cling to unheated surfaces such as the wall of the channel o~ the nuclear reactor. Steam usually builds up along the core portion of the fuel bundle or in the upper portion of the fuel bundle when the bundle i~ positioned on a horizontal plane. The segregation o~ steam poses a problem in that portions of the ~uel bundle operate at higher quality (i.e. more steam than water) than the remainder of the fuel bundle and therefore may more readily reach critical power.
It should be understood that critical power is that power at which the coolant flowing around the fuel rods in the ~uel bundle in a nuclear reactor is not able to extract the heat 7zg generated in a nuclear fuel rod causing fuel failure which may cause reactor shutdo~m directly or indirectly.
SUMMARY OF THE INVENTION
According to this invention there is provided a nuclear fuel bundle comprising a plurality of fuel rods and a flow splitter apparatus which sectionalizes the bundle into a plurality of compartments which limit v~pour stratification across the bundle to that which occurs in each compartment.
Additionally 7 the flow splitter apparatus includes unheated surfaces along which liquid coolant may flow and inhibit vapour stratification across the bundle. The unheated surfaces can be, for example, a tubular member running the length of the fuel bundle core, ~lanar surfaces extending from the fuel bundle periphery to the core, and planar surfaces extending from the periphery partially into the fuel bundle interior.
The sectionalizing provides physical boundaries to the vapour stratification process confining vapour (or steam) ; blanketing. The unheated surfaces provide a path along which .:
liquid coolant flows suppressing build-up of vapour coolant within each compartment of the fuel bundle.
The nuclear fuel bundle may also provide flow strippers which protrude from the unheated surfaces to deflect liquid ~` coolant into flow sub channels defined by each compartment.
BRIEF DESCRIPTION OF THE DRAWINGS
For a better understanding of the nature and objects of the invention reference may be had to the following detailed ~" description taken in conjunction with the accompanying diagram-matic drawings in which:
Fig. 1 is a side view, broken away :in part, of a nuclear fuel bundle including the flow splitter apparatus, Fig. 2 is a sectional view of the fuel bundle and flow splitter apparatus on Section II II in Fig. 1, Fig. 3 is an en~ view of the fuel bundle and splitter apparatus showing the assembly in a nuclear reactor channel, and Fig. 4 is a sectional view of another embodiment showing additional flow splitters entering only part way into the bundle.
It should be noted that the embodiment to be described in the accompanying drawings is for a nuclear fuel bundle having a plurality of fuel rods which form a series of concentric rings.
It should be understood that the flow splitter apparatus may be used with matrix-type9 or polygonal-type bundle arrays.
Fig. 1 relates to a nuclear fuel bundle generally indicated at 10. The fuel element consists of a plurality of fuel rods arranged to form a series of concentric rings. The fuel rods indicated by reference numeral 14 are fuel rods which form the outer ring of the fuel bundle 10.
A flow splitter apparatus indicated at 16 runs the entire length of the fuel bundle 10 and extends from the interior 18 of fuel bundle 10 to the exterior 20.
Spacers 22 are welded to fuel rods 14 and act to space i 20 the fuel element 10 relative to the wall of the channel of a nuclear reactor. Spacers 24 welded to fuel rods 14 are also spot welded to toroidal member 26 which surrounds the fuel element 10. It should be understood that the protrusion of spacers 24 from fuel rods 14 will be less than the protrusion of spacers 22 because toroidal member 26 will be positioned adjacent the wall of the channel in a manner similar to spacers 22.
Toroidal member 26 is joined to flow splitter apparatus 16 at exterior edges 28.
m e flow splitter apparatus 16 of Fig. 1 shows two planar surfaces 30 each having a plurality of' teeth 32 joined to end rings 34 of fuel bundle 10 End rings 34 are also co~lected to end caps 36 of fuel rods 14. Planar surfaces 30 are attached to a tubular member 3~. The tubular member 38 (which may be seen more clearly in Fig. 2~ surrounds the fuel rod positioned in the centre of the fuel bundle and extends sub,stantially the length of the fuel bundle or as much as may be desired. The centre portion 40 of member 38 may be filled by a fuel rod or left empty. The centre portion 40 may be used to Join two or more fuel bundles together in a continuation.
Referring now to Fig. 2 the flow splitter apparatus is shown consisting of six planar surfaces 30 which divide the fuel bundle into six segmental compartments 42. Planar surfaces 30 each provide an unheated surface which has a length substan-tially equal to the length of the fuel bundle 10 and extends radially from tubular member 38 to toroidal member 26.
A plurality of spacers generally indicated as 44 provide ' the desired spacing between each of the fuel rods as well as between the fuel rods and planar surfaces 30.
It should be understood that the planar surfaces 30 each provide an unheated surface along which water flows in addition to being a surface that co~petes with the wall of the channel for its water. The presence of the unheated tubular member 38 at the centre of the fuel element 10 provides a surface along which water may flow through the core of the bundle whether or not this centre portion 40 is filled with a fuel rod. In Fig. 2 the centre portion 40 is shown not filled with a fuel rod.
It should be understood that any number of planar surfaces may be used to divide the bundle into as many compart-ments as may be desiredO Compartments 42 formed by planar surfaces 30 limit the quantity of steam segregated from water in the upper half of the fuel bundle 10 when the fuel bundle ' ~ 72~9 is positioned horizontally and increase the amount of water ~lowing through the interior of the fuel bundle.
The use of the flow splitter apparatus as shown in the drawings provides for the operation of the fuel bundle at a more evenly dispersed quality which results in the critical power ratio of the fuel bundle being increased.
Flow strippers 46 protrude from planar surfaces 30 in Fig. 2. Flow strippers 46 deflect water flowing along surfaces 30 onto the fuel rods and into the flow sub channels 10 47. The flow strippers 46 may be attached to or formed from surfaces 30. Flow strippers 46 may be formed by cutting into surfaces 30 and folding flaps formed from the incision back into the compartments.
The flow splitter apparatus should be formed ~rom a suitable material which may be zironium alloy.
Referring now to Fig. 3 the fuel bundle lO is shown within wall 48 of the nuclear reactor channel. Spacers 22 and toroidal member 26 make contact with wall 48. End ring plates 34 are shown having openings which receive the teeth portion of planar surfaces 30 at locations 50. The flow splitter - apparatus is spot welded to end plates 34 at 50 in a similar manner as plates 34 are spot welded to end caps at 52. In this embodiment centre portion 40 of tubular member 38 is filled with a fuel rod.
In the embodiment of Fig. 4 additional flow splitter planar surfaces 31 enter only part way into the centre of the bundle 10. The flow strippers may be small plates 54 attached to planar surfaces 30 or 31. Plates 50 may also be employed to position fuel elements or rods in their desired locations.
In another embodiment of the invention, such as a fuel bundle having a square matrix-type bundle, a centre tubular .
11C~4 7Z9 member may not be necessary and the compartments might be sub-stantially rectangular instead of segmental~ In this embodiment it should be understood that a toroidal member may be of different shape, ma-y not surround the fuel bundle or may not even be present.
It should be understood that the two phase regime as mentioned hereinabove as consisting of water and steam may also include another coolant and a ~apour of that coolant such as borated water and its associated vapour.
:,..
This invention relates to a nuclear ~uel bundle for a nuclear reactor having a flow splitter apparatus. The splitter apparatus provides unheated surfaces along which liquid coolant flows through the interior of the fuel bundle.
A fuel bundle that is commonly used consists of an array of fuel rods having a longitudinal axis positioned within a channel of a nuclear reactor on a horizontal plane. Coolant passing through the ~uel bundle usually enters a two pha~e regime, ~or example, steam and water. Water has a tendency to cling to unheated surfaces such as the wall of the channel o~ the nuclear reactor. Steam usually builds up along the core portion of the fuel bundle or in the upper portion of the fuel bundle when the bundle i~ positioned on a horizontal plane. The segregation o~ steam poses a problem in that portions of the ~uel bundle operate at higher quality (i.e. more steam than water) than the remainder of the fuel bundle and therefore may more readily reach critical power.
It should be understood that critical power is that power at which the coolant flowing around the fuel rods in the ~uel bundle in a nuclear reactor is not able to extract the heat 7zg generated in a nuclear fuel rod causing fuel failure which may cause reactor shutdo~m directly or indirectly.
SUMMARY OF THE INVENTION
According to this invention there is provided a nuclear fuel bundle comprising a plurality of fuel rods and a flow splitter apparatus which sectionalizes the bundle into a plurality of compartments which limit v~pour stratification across the bundle to that which occurs in each compartment.
Additionally 7 the flow splitter apparatus includes unheated surfaces along which liquid coolant may flow and inhibit vapour stratification across the bundle. The unheated surfaces can be, for example, a tubular member running the length of the fuel bundle core, ~lanar surfaces extending from the fuel bundle periphery to the core, and planar surfaces extending from the periphery partially into the fuel bundle interior.
The sectionalizing provides physical boundaries to the vapour stratification process confining vapour (or steam) ; blanketing. The unheated surfaces provide a path along which .:
liquid coolant flows suppressing build-up of vapour coolant within each compartment of the fuel bundle.
The nuclear fuel bundle may also provide flow strippers which protrude from the unheated surfaces to deflect liquid ~` coolant into flow sub channels defined by each compartment.
BRIEF DESCRIPTION OF THE DRAWINGS
For a better understanding of the nature and objects of the invention reference may be had to the following detailed ~" description taken in conjunction with the accompanying diagram-matic drawings in which:
Fig. 1 is a side view, broken away :in part, of a nuclear fuel bundle including the flow splitter apparatus, Fig. 2 is a sectional view of the fuel bundle and flow splitter apparatus on Section II II in Fig. 1, Fig. 3 is an en~ view of the fuel bundle and splitter apparatus showing the assembly in a nuclear reactor channel, and Fig. 4 is a sectional view of another embodiment showing additional flow splitters entering only part way into the bundle.
It should be noted that the embodiment to be described in the accompanying drawings is for a nuclear fuel bundle having a plurality of fuel rods which form a series of concentric rings.
It should be understood that the flow splitter apparatus may be used with matrix-type9 or polygonal-type bundle arrays.
Fig. 1 relates to a nuclear fuel bundle generally indicated at 10. The fuel element consists of a plurality of fuel rods arranged to form a series of concentric rings. The fuel rods indicated by reference numeral 14 are fuel rods which form the outer ring of the fuel bundle 10.
A flow splitter apparatus indicated at 16 runs the entire length of the fuel bundle 10 and extends from the interior 18 of fuel bundle 10 to the exterior 20.
Spacers 22 are welded to fuel rods 14 and act to space i 20 the fuel element 10 relative to the wall of the channel of a nuclear reactor. Spacers 24 welded to fuel rods 14 are also spot welded to toroidal member 26 which surrounds the fuel element 10. It should be understood that the protrusion of spacers 24 from fuel rods 14 will be less than the protrusion of spacers 22 because toroidal member 26 will be positioned adjacent the wall of the channel in a manner similar to spacers 22.
Toroidal member 26 is joined to flow splitter apparatus 16 at exterior edges 28.
m e flow splitter apparatus 16 of Fig. 1 shows two planar surfaces 30 each having a plurality of' teeth 32 joined to end rings 34 of fuel bundle 10 End rings 34 are also co~lected to end caps 36 of fuel rods 14. Planar surfaces 30 are attached to a tubular member 3~. The tubular member 38 (which may be seen more clearly in Fig. 2~ surrounds the fuel rod positioned in the centre of the fuel bundle and extends sub,stantially the length of the fuel bundle or as much as may be desired. The centre portion 40 of member 38 may be filled by a fuel rod or left empty. The centre portion 40 may be used to Join two or more fuel bundles together in a continuation.
Referring now to Fig. 2 the flow splitter apparatus is shown consisting of six planar surfaces 30 which divide the fuel bundle into six segmental compartments 42. Planar surfaces 30 each provide an unheated surface which has a length substan-tially equal to the length of the fuel bundle 10 and extends radially from tubular member 38 to toroidal member 26.
A plurality of spacers generally indicated as 44 provide ' the desired spacing between each of the fuel rods as well as between the fuel rods and planar surfaces 30.
It should be understood that the planar surfaces 30 each provide an unheated surface along which water flows in addition to being a surface that co~petes with the wall of the channel for its water. The presence of the unheated tubular member 38 at the centre of the fuel element 10 provides a surface along which water may flow through the core of the bundle whether or not this centre portion 40 is filled with a fuel rod. In Fig. 2 the centre portion 40 is shown not filled with a fuel rod.
It should be understood that any number of planar surfaces may be used to divide the bundle into as many compart-ments as may be desiredO Compartments 42 formed by planar surfaces 30 limit the quantity of steam segregated from water in the upper half of the fuel bundle 10 when the fuel bundle ' ~ 72~9 is positioned horizontally and increase the amount of water ~lowing through the interior of the fuel bundle.
The use of the flow splitter apparatus as shown in the drawings provides for the operation of the fuel bundle at a more evenly dispersed quality which results in the critical power ratio of the fuel bundle being increased.
Flow strippers 46 protrude from planar surfaces 30 in Fig. 2. Flow strippers 46 deflect water flowing along surfaces 30 onto the fuel rods and into the flow sub channels 10 47. The flow strippers 46 may be attached to or formed from surfaces 30. Flow strippers 46 may be formed by cutting into surfaces 30 and folding flaps formed from the incision back into the compartments.
The flow splitter apparatus should be formed ~rom a suitable material which may be zironium alloy.
Referring now to Fig. 3 the fuel bundle lO is shown within wall 48 of the nuclear reactor channel. Spacers 22 and toroidal member 26 make contact with wall 48. End ring plates 34 are shown having openings which receive the teeth portion of planar surfaces 30 at locations 50. The flow splitter - apparatus is spot welded to end plates 34 at 50 in a similar manner as plates 34 are spot welded to end caps at 52. In this embodiment centre portion 40 of tubular member 38 is filled with a fuel rod.
In the embodiment of Fig. 4 additional flow splitter planar surfaces 31 enter only part way into the centre of the bundle 10. The flow strippers may be small plates 54 attached to planar surfaces 30 or 31. Plates 50 may also be employed to position fuel elements or rods in their desired locations.
In another embodiment of the invention, such as a fuel bundle having a square matrix-type bundle, a centre tubular .
11C~4 7Z9 member may not be necessary and the compartments might be sub-stantially rectangular instead of segmental~ In this embodiment it should be understood that a toroidal member may be of different shape, ma-y not surround the fuel bundle or may not even be present.
It should be understood that the two phase regime as mentioned hereinabove as consisting of water and steam may also include another coolant and a ~apour of that coolant such as borated water and its associated vapour.
:,..
Claims (7)
1. A nuclear fuel bundle comprising a plurality of fuel rods, said bundle arrange for operation in a fluid cooled reactor in which a liquid is normally vaporized during operation of the reactor, means to limit the separation of liquid and vapour phases of the fluid within the fuel bundle comprising a plurality of flat planar flow splitter members separating said fuel bundle into a plurality of parallel compartments each extending from one end of said bundle to the other and enclosing a plurality of said fuel rods.
2. A nuclear fuel bundle as claimed in claim 1 wherein said flow splitter members are not directly heated by the fuel in said bundle.
3. A nuclear fuel bundle as claimed in claim 1 wherein said flow splittter members include flow strippers for deflecting fluid flowing along the surfaces of said flow splitter members to further limit phase separation of said fluid.
4. A nuclear fuel bundle as claimed in claim 1 wherein the bundle is cylindrical and said flow splitter members include a plurality of planar members extending radially from the center of said bundle to the outer periphery of said bundle.
5. A nuclear fuel bundle as claimed in claim 4 including a plurality of planar members extending radially inward from the periphery of said bundle only partially into the center of said bundle.
6. A nuclear fuel bundle as claimed in claims 4 or 5 wherein said planar members are attached to a support member surrounding said bundle.
7. A nuclear fuel bundle as claimed in claim 4 wherein said planar members are attached to a tube at the center of said bundle.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA306,420A CA1104729A (en) | 1978-06-28 | 1978-06-28 | Apparatus for improving critical power ratio in a nuclear fuel bundle |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA306,420A CA1104729A (en) | 1978-06-28 | 1978-06-28 | Apparatus for improving critical power ratio in a nuclear fuel bundle |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1104729A true CA1104729A (en) | 1981-07-07 |
Family
ID=4111803
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA306,420A Expired CA1104729A (en) | 1978-06-28 | 1978-06-28 | Apparatus for improving critical power ratio in a nuclear fuel bundle |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1104729A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1995024042A1 (en) * | 1994-03-02 | 1995-09-08 | Atomic Energy Of Canada Limited | Critical power enhancement system for a pressurized fuel channel type nuclear reactor using chf enhancement appendages |
| US5479390A (en) * | 1980-07-16 | 1995-12-26 | Discovision Associates | System for recording digital information in a pulse-length modulation format |
-
1978
- 1978-06-28 CA CA306,420A patent/CA1104729A/en not_active Expired
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5479390A (en) * | 1980-07-16 | 1995-12-26 | Discovision Associates | System for recording digital information in a pulse-length modulation format |
| WO1995024042A1 (en) * | 1994-03-02 | 1995-09-08 | Atomic Energy Of Canada Limited | Critical power enhancement system for a pressurized fuel channel type nuclear reactor using chf enhancement appendages |
| US5493590A (en) * | 1994-03-02 | 1996-02-20 | Atomic Energy Of Canada Limited | Critical power enhancement system for a pressurized fuel channel type nuclear reactor using CHF enhancement appendages |
| GB2301475A (en) * | 1994-03-02 | 1996-12-04 | Ca Atomic Energy Ltd | Critical power enhancement system for a pressurized fuel channel type nuclear reactor using chf enhancement appedages |
| GB2301475B (en) * | 1994-03-02 | 1997-12-17 | Ca Atomic Energy Ltd | Critical power enhancement system for a pressurized fuel channel type nuclear reactor using chf enhancement appendages |
| CN1102292C (en) * | 1994-03-02 | 2003-02-26 | 加拿大原子能有限公司 | Critical power enhancement system for a pressurized fuel channel type nuclear reactor using CHF enhancement appendages |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |