CA1174377A - Flow-through shield plug - Google Patents
Flow-through shield plugInfo
- Publication number
- CA1174377A CA1174377A CA000386193A CA386193A CA1174377A CA 1174377 A CA1174377 A CA 1174377A CA 000386193 A CA000386193 A CA 000386193A CA 386193 A CA386193 A CA 386193A CA 1174377 A CA1174377 A CA 1174377A
- Authority
- CA
- Canada
- Prior art keywords
- shield plug
- inboard
- fuel
- lobes
- plug
- 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
- G21C11/00—Shielding structurally associated with the reactor
- G21C11/02—Biological shielding ; Neutron or gamma shielding
- G21C11/026—Biological shielding ; Neutron or gamma shielding in apertures or channels through a wall
-
- 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
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Biomedical Technology (AREA)
- General Health & Medical Sciences (AREA)
- Molecular Biology (AREA)
- Plasma & Fusion (AREA)
- General Engineering & Computer Science (AREA)
- High Energy & Nuclear Physics (AREA)
- Monitoring And Testing Of Nuclear Reactors (AREA)
Abstract
Case 2770 FLOW-THROUGH SHIELD PLUG
ABSTRACT OF THE DISCLOSURE
A radiation shield plug for use with a pressure tube type nuclear reactor incorporates a first outboard set of flow passages for passage of liquid coolant longitudinally therepast, and a second inboard set of flow passages for passage of the coolant longitudinally therepast, the outboard portion of the shield plug including lobe portions located in axial blocking relation with the inboard flow passages, to substantially preclude the direct passage of radiation past the plug from nuclear fuel located in a fuel channel within which the shield plug is located. The plug may also incorporate a peripheral groove to receive latch fingers of the fuel channel in entered gripping relation therein.
ABSTRACT OF THE DISCLOSURE
A radiation shield plug for use with a pressure tube type nuclear reactor incorporates a first outboard set of flow passages for passage of liquid coolant longitudinally therepast, and a second inboard set of flow passages for passage of the coolant longitudinally therepast, the outboard portion of the shield plug including lobe portions located in axial blocking relation with the inboard flow passages, to substantially preclude the direct passage of radiation past the plug from nuclear fuel located in a fuel channel within which the shield plug is located. The plug may also incorporate a peripheral groove to receive latch fingers of the fuel channel in entered gripping relation therein.
Description
Case 2770 FLOW-THROUGH SHIELD PLUG
This invention is directed to a radiation shield plug, particularly for use in a pressure tube nuclear reactor.
Nuclear reactors of the Canadian Deuteriu~ Uranium (CANDU) type rely upon the passage of liquid heavy water coolant along pressure tube fuel channels positioned within a calandria having the pressure tubes extending through the ends thereof, for accessing the fuel externally in a periodical recharging mode.
Earlier types of reactor incorporated radiation shield plugs located within an enlarged portion of the respective fuel channels, to permit the flow of coolant in bypass relation to the shield plugs.
By pr~viding radiation shield plugs permitting the passage of liquid coolant through the shield plug cross section, the characteristics of some reactor designs can be significantly enhanced in that a more slender fuel channel may be utilized, and the spacing of the fuel channels reduced, with consequently enhanced neutron efficiency leading to improved fuel utilization; and significantly diminished inventory of heavy water (deuterium) within the respective fuel channels where it serves as coolant, and within the calandria where it serves as a moderator.
Accordingly, there is provided a radiation shield plug permitting the ready passage of liquid coolant 3~
:
Case 2770 ~74377 through the shield plug, whilst substantially precluding the leakage of radiation along the fuel channel past the shield plug.
Thus, a radiation shield plug for use in a nuclear reactor, within a cylindrical fuel channel of predetermined diameter has a diameter less than that of the fuel channel, to permit ready passage of the shield plug therealong the shield plug having an outboard portion and an inboard portion, each pc)rtion having shaped lobes extending at least partially along the respective shield plug portion and defining a plurality of coolant flow channels through the shield plug, the lobes of the outboard portion extending in substantially axial blocking relation with the coolant flow channels of the inboard portion.
The lobes of the outboard shieldplug portion usually extend in axial overlapping relation with a portion of the length of the lobes of the inboard portion, the over-lapping lobe portions being streamlined in order to minimize pressure drop in the coolant flowing therepast.
The selection of suitable streamlined profiles for the transition portion of the shield plug can result in a plurality of flow passages of substantially uniform cross section for the whole shieldplug, possessing no sudden flow discontinuities to generate significant pressure losses when in use. Certain embodiments of the invention are described, reference being made to the accompanying drawings, wherein;
Figure 1 is a general view of a shield plug in accordance with the present invention;
Figure 2 is a diametrical section of a fuel channel containing the subject shield plug in latched relation therein;
Figures 3 and 4 are views at 3-3 and 4-4 of Figure l, respectively, showing cross sections of the plug inboard portion.
1~74377 Case 2770 Referring to the drawings, the shield plug lO has an outboard portion 12 and an inboard portion 14, being thus referred to with reference to the attitude of the shield plug 10 within a fuel channel 16 wherein the inboard portion 14 faces inwardly towards the interior of the fuel channel 16, wherein the nuclear fuel (not shown) is located, and in contact with the attached shield plug nose piece 22.
In the illustrated embodiment each portion 12, 14 of the unitary shield plug 10 has three equally spaced lobes 18, each lobe 18 subtending an angle of 60 to thereby form longitudinal flow passages 20 therebetween.
The respective lobes 18 of the inboard portion 14 are offset 60 from the lobes 18 of the outboard portion 12.
In the case of Figure 4, the view of the outboard portion 12, wherein the lobes 18 thereof would appear within the flow passages 20 of Figure 4, has been omitted for the sake of clarity, as the respective relationships are sufficiently portrayed in Figure 1.
Referring to Figure 3, the lobes 18 of the unitary shield plug are contained within an inboard sleeve which is provided to improve the support of the inboard end of the shield plug in the fuel channel.
A tapered section of the sleeve has flow holes 28 (Figure 2) for improved flow past the nose piece 22.
The face 26 of the nose piece 22 constitutes a flow transition zone for liquid coolant, being the axial location whereat the shield plug lO contacts the end plate of the outboard one of the fuel elements (not shown) which ~ are contained within the fuel channel 16, in positioned ; 30 relation against the nose piece 22.
Latch fingers 30 forming part of the fuel channel 16, which do not constitute part of the present invention.,.
extend into peripheral recesses 32 of the lobes 18, so as to axiall~ position the shield plug 10 within the fuel : . 35 channel 16, against hydraulic flow forces of outflowing ~ coolant liquid flowing axially along the channel 16.
.
~7~377 Case 2770 Prior art shield plugs, being of solid cross section, required the provision of a flow annulus surrounding the solid shield plug. Thus, shield plugs according to the present invention, by permitting coolant liquid flow through the plug, make possible the adoption of closer spacing of the fuel channels, thereby significantly reducing calandria size requirements, and enhancing neutron efficiency. Also of course, the deuterium inventory requirement is significantly reduced with regard to coolant deuterium and moderator deuterium.
A further practical advantage of the subject shield plugs is their utilization in positioning the string of fuel bundles, in accurate axial location with the fuel channel.
This invention is directed to a radiation shield plug, particularly for use in a pressure tube nuclear reactor.
Nuclear reactors of the Canadian Deuteriu~ Uranium (CANDU) type rely upon the passage of liquid heavy water coolant along pressure tube fuel channels positioned within a calandria having the pressure tubes extending through the ends thereof, for accessing the fuel externally in a periodical recharging mode.
Earlier types of reactor incorporated radiation shield plugs located within an enlarged portion of the respective fuel channels, to permit the flow of coolant in bypass relation to the shield plugs.
By pr~viding radiation shield plugs permitting the passage of liquid coolant through the shield plug cross section, the characteristics of some reactor designs can be significantly enhanced in that a more slender fuel channel may be utilized, and the spacing of the fuel channels reduced, with consequently enhanced neutron efficiency leading to improved fuel utilization; and significantly diminished inventory of heavy water (deuterium) within the respective fuel channels where it serves as coolant, and within the calandria where it serves as a moderator.
Accordingly, there is provided a radiation shield plug permitting the ready passage of liquid coolant 3~
:
Case 2770 ~74377 through the shield plug, whilst substantially precluding the leakage of radiation along the fuel channel past the shield plug.
Thus, a radiation shield plug for use in a nuclear reactor, within a cylindrical fuel channel of predetermined diameter has a diameter less than that of the fuel channel, to permit ready passage of the shield plug therealong the shield plug having an outboard portion and an inboard portion, each pc)rtion having shaped lobes extending at least partially along the respective shield plug portion and defining a plurality of coolant flow channels through the shield plug, the lobes of the outboard portion extending in substantially axial blocking relation with the coolant flow channels of the inboard portion.
The lobes of the outboard shieldplug portion usually extend in axial overlapping relation with a portion of the length of the lobes of the inboard portion, the over-lapping lobe portions being streamlined in order to minimize pressure drop in the coolant flowing therepast.
The selection of suitable streamlined profiles for the transition portion of the shield plug can result in a plurality of flow passages of substantially uniform cross section for the whole shieldplug, possessing no sudden flow discontinuities to generate significant pressure losses when in use. Certain embodiments of the invention are described, reference being made to the accompanying drawings, wherein;
Figure 1 is a general view of a shield plug in accordance with the present invention;
Figure 2 is a diametrical section of a fuel channel containing the subject shield plug in latched relation therein;
Figures 3 and 4 are views at 3-3 and 4-4 of Figure l, respectively, showing cross sections of the plug inboard portion.
1~74377 Case 2770 Referring to the drawings, the shield plug lO has an outboard portion 12 and an inboard portion 14, being thus referred to with reference to the attitude of the shield plug 10 within a fuel channel 16 wherein the inboard portion 14 faces inwardly towards the interior of the fuel channel 16, wherein the nuclear fuel (not shown) is located, and in contact with the attached shield plug nose piece 22.
In the illustrated embodiment each portion 12, 14 of the unitary shield plug 10 has three equally spaced lobes 18, each lobe 18 subtending an angle of 60 to thereby form longitudinal flow passages 20 therebetween.
The respective lobes 18 of the inboard portion 14 are offset 60 from the lobes 18 of the outboard portion 12.
In the case of Figure 4, the view of the outboard portion 12, wherein the lobes 18 thereof would appear within the flow passages 20 of Figure 4, has been omitted for the sake of clarity, as the respective relationships are sufficiently portrayed in Figure 1.
Referring to Figure 3, the lobes 18 of the unitary shield plug are contained within an inboard sleeve which is provided to improve the support of the inboard end of the shield plug in the fuel channel.
A tapered section of the sleeve has flow holes 28 (Figure 2) for improved flow past the nose piece 22.
The face 26 of the nose piece 22 constitutes a flow transition zone for liquid coolant, being the axial location whereat the shield plug lO contacts the end plate of the outboard one of the fuel elements (not shown) which ~ are contained within the fuel channel 16, in positioned ; 30 relation against the nose piece 22.
Latch fingers 30 forming part of the fuel channel 16, which do not constitute part of the present invention.,.
extend into peripheral recesses 32 of the lobes 18, so as to axiall~ position the shield plug 10 within the fuel : . 35 channel 16, against hydraulic flow forces of outflowing ~ coolant liquid flowing axially along the channel 16.
.
~7~377 Case 2770 Prior art shield plugs, being of solid cross section, required the provision of a flow annulus surrounding the solid shield plug. Thus, shield plugs according to the present invention, by permitting coolant liquid flow through the plug, make possible the adoption of closer spacing of the fuel channels, thereby significantly reducing calandria size requirements, and enhancing neutron efficiency. Also of course, the deuterium inventory requirement is significantly reduced with regard to coolant deuterium and moderator deuterium.
A further practical advantage of the subject shield plugs is their utilization in positioning the string of fuel bundles, in accurate axial location with the fuel channel.
Claims (7)
1. A radiation shield plug for use in a cylindrical fuel channel of a nuclear reactor, said channel being of predetermined diameter, said shield plug having a diameter less than said predetermined diameter to permit ready insertion within and extraction from said fuel channel, said shield plug having a first, outboard portion and a second, inboard portion, each said portion having lobes extending at least partially along the respective said portion, said lobes defining in use within said fuel channel a plurality of coolant flow channels, the lobes of said outboard portion extending in substantial axial blocking relation with said coolant flow channels of said inboard portion, to substantially preclude direct passage for radiation from within said channel past said shield plug.
2. The shield plug according to claim 1, said lobes of said outboard portion extending in axial overlapping relation with a portion of the length of the other said lobes, said overlapping lobe portions being tapered to facilitate the passage of liquid coolant therepast.
3. The shield plug according to claim 1 having a circumferential groove about said lobes of the plug, to receive latch fingers of a fuel latch in entered engaging relation therewith.
4. The shield plug according to claim 1, claim 2 or 3, said inboard and outboard portions comprising a unitary construction.
5. The shield plug according to claim 1, claim 2 or claim 3, including an attached nose piece secured to said inboard portion in axial alignment therewith, to receive a nuclear fuel bundle in axially supported relation thereagainst.
- 6 - Case 2770
- 6 - Case 2770
6. A radiation shield plug as claimed in claim 1 in combination with a nuclear reactor having a plurality of pressure tube fuel channels, said fuel channels each having a pressure connection thereto located outboard of said shield plug, to provide pressurized liquid coolant to the respective fuel channel for passage past the shield plug into cooling relation with nuclear fuel positioned inboard of the shield plug.
7. The shield plug according to claim 1, claim 2 or claim 3 including an attached nose piece secured to said inboard portion at the inboard end thereof, having lobe portions positioned in aligned relation with said inboard lobe portions.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000386193A CA1174377A (en) | 1981-09-18 | 1981-09-18 | Flow-through shield plug |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000386193A CA1174377A (en) | 1981-09-18 | 1981-09-18 | Flow-through shield plug |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1174377A true CA1174377A (en) | 1984-09-11 |
Family
ID=4120990
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000386193A Expired CA1174377A (en) | 1981-09-18 | 1981-09-18 | Flow-through shield plug |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1174377A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9418765B2 (en) | 2013-03-14 | 2016-08-16 | Roger Ian LOUNSBURY | Nuclear reactor cores comprising a plurality of fuel elements, and fuel elements for use therein |
-
1981
- 1981-09-18 CA CA000386193A patent/CA1174377A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9418765B2 (en) | 2013-03-14 | 2016-08-16 | Roger Ian LOUNSBURY | Nuclear reactor cores comprising a plurality of fuel elements, and fuel elements for use therein |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEC | Expiry (correction) | ||
| MKEX | Expiry |