US3391280A

US3391280A - Fire protection shield for radioactive shipping container

Info

Publication number: US3391280A
Application number: US409398A
Authority: US
Inventors: Charles F Bonilla; Steven H Brown; George P Miller
Original assignee: Nat Lead Co
Current assignee: NL Industries Inc
Priority date: 1964-11-06
Filing date: 1964-11-06
Publication date: 1968-07-02
Anticipated expiration: 1985-07-02
Also published as: DE1514283B2; DE1514283A1; DK122915C; BE671850A; GB1120397A; DK122915B

Description

ULHHUII Hvvnn July 2, 1968 c, F BOMLLA ET AL FIRE PROTECTION SHIELD FOR RADIOACTIVE SHIPPING CONTAINER 8 Sheets-Sheet 1 Filed Nov.

INVENTORS cumzuas P. BomLLA, s-revau H-BEOwN @QEQQQE P. MILLER AGENT FICA- July 2, 1968 c F BONILLA ET AL 3,391,280

FIRE PROTECTION SHIELD FOR RADIOACTIVE SHIPPING CONTAINER Filed NOV. 6, 1964 8 Sheets-Sheet CHARLES Pmaomua, $TEVEN H. 520mm caeoxzcre P. NHLLEIZ.

July 2, 1968 c BONlLLA ET AL 3,391,280

FIRE PROTECTION SHIELD FOR RADIOACTIVE SHIPPING CONTAINER 8 Sheets-Sheet 3 Filed Nov. 6, 1964 n R NR Ouwm" W L m w mBB. PHD. S E aw R 2V0 m CS Q July 2, 1968 c BONILLA ET AL 3,391,280

FIRE PROTECTION SHIELD FOR RADIOACTIVE SHIPPING CONTAINER Filed Nov. 6, 1964 8 Sheets-Sheet 4 S E t o I M MM I V; E w a M N W r 102 A H I E I I m H mv 3 Y B 8 05 \Ag nu AGENT- CONTAINER y 1968 c. F. BONILLA ET FIRE PROTECTION SHIELD FOR RADIOACTIVE SHIPPING 8 Sheets-Sheet 5 Filed Nov.

INVENTOR$ CHARLES i-.BON\LLR,

suavsu aoum ErGEoReE P. M|LLER AGEN T y 2, 1968 c. F. BONILLA ET AL 3,391,280

FIRE PROTECTION SHIELD FOR RADIOACTIVE SHIPPING CONTAINER Filed Nov. 6, 1964 8 Sheets-Sheet 6 INVENTORS CHARLEs P. raomum, STEVEN H. 1320mm SrGEOEGE P. MILLER July 2, 1968 c; BOMLLA ET AL. 3,391,280

FIRE PROTECTION SHIELD FOR RADIOACTIVE SHIPPING CONTAINER 8 Sheets-Sheet '7 Filed Nov. 6, 1964 NNm Own

INVENTORS CHRRLES F. BOMLL $TEVEN &'GEOR6E BY H BRowu P. MlLLEE HQEN 7 KO T\/ July 2, 1968 c BOMLLA ET AL 3,391,280

FIRE PROTECTION SHIELD FOR RADIOACTIVE SHIPPING CONTAINER 8 Sheets-Sheet 8 Filed Nov. 6, 1964 m T O A T L a N m @HMH m MWE E g 8v 8% mwm M Sq M s m m 2E m 9H 0; m 5w I N9 M m cq M :w W 3V United States Patent 3,391,280 FIRE PROTECTION SHIELD FOR RADIOACTHE SHIPPING CONTAINER (iharies F. lionilla, Tenaliy, and Steven H. Brown, Montciair, N.J., and George P. Miiler, Cincinnati, Ohio, assignors to National Lead Company, New York, N.Y., a corporation of New Jersey Filed Nov. 6, 1964, Ser. No. 409,398 13 Claims. (Cl. 250-108) ABSTRACT OF THE DKSCLGSURE A shipping container for radioactive material is surrounded by a spaced fire protection shield. The fire protection shield allows air to freely circulate within the shield means at normal temperatures to remove decayed heat, and air iiow control means is provided to stop the air circulation at a predetermined temperature to prevent hot air from entering the shield means and heating the container.

The present invention relates to new and novel protective shield means, and more particularly to a fire shield for use with shipping containers having radioactive material therein.

The shield means of the present invention is particularly adapted for use with shipping containers which are utilized for shipping radioactive fuel elements such as used in nuclear reactors, such shipping containers ordinarily having lead or a similar substance for the attenuation of harmful gamma radiation.

The shield means of the present invention is particularly designed to protect such shipping containers from the damaging effects of accidental fire exposure, the shield means also serving to effectively protect the container from solar radiation as well as from dirt and other foreign matter and further to prevent accidental damage to the container.

An important feature of the invention is the fact that the shield means does serve to protect the shipping container as described above while at the same time permitting the discharge of the decay heat which occurs during normal use of the shipping container. In order to accomplish this last-mentioned function, the shield means of the present invention incorporates a construction whereby air is allowed to freely circulate within the shield means and about the enclosed container so as to carry heat away from the container which effectively removes the decay heat and permits the shipping container to be effectively employed for its intended function.

The container is protected from external sources of heat by walled portions of a heat insulating construction. Suitable battles are provided so that direct radiation does not fall upon the enclosed container from outside of the shield means.

A further important feature of the invention is the provision of air flow control means which operate to arrest or stop the air circulation through the body means at a predetermined temperature. :In other words, it is desirable to have air circulation through the body means during normal operating temperatures. However, when the temperature rises above a certain point, such air circulation is undesirable since it has a tendency to heat up the enclosed container rather than to cool it as is the normal case.

Accordingly, when the air circulating through the shield means reaches such a predetermined temperature, the air flow control means automatically prevents further circulation of the air so as to prevent the hot air from entering the shield means and heating up the container means.

ice

The air flow control means may take a number of different forms, and in the present invention, two separate modifications are illustrated. In a first modification, intumescent material is employed which is adapted to swell up and close off an air flow passage so as to prevent further circulation of air through the shield means. In the second modification, mechanically operated control valve means is employed for controlling the circulation of air through the shield means.

The shipping containers normally employed for use with radioactive material generally incorporate lead to attenuate gamma radiation, and voids are generally provided to permit expansion of the lead under heat. There is however, no known way to economically and effectively incorporate a sufficiently large void which would safely and efficiently provide for all of the expansion of the lead which would occur as the lead melts and rises to the elevated temperatures which can occur under certain flame temperature conditions. Also, the steel body means of such containers does not have the ability to reliably contain the molten lead under the pressures which may develop. Accordingly, it is necessary to provide a protective shield means as contemplated by the present invention so that there is no loss of effectiveness of the lead shield of the shipping container itself.

An object of the present invention is to provide a new and novel protective shield means for containers having radioactive material therein and wherein the containers are protected from fire, solar radiation, foreign matter and accidental damage and which further assures that there will be no loss of the effectiveness of the lead shield of the container when subjected to high temperature fire conditions.

Another object of the invention is the provision of a protective shield means for containers having radioactive material therein wherein the shield means incorporates a heat insulating wall construction and wherein baffle means is provided for preventing direct radiation from hitting the container surface.

Still another object of the invention is to provide protective shield means for shipping containers having radioactive material therein wherein air is permitted to circulate within the shield means and about an enclosed container to remove the decay heat from the container during normal utilization of the apparatus.

Still another object of the invention is to provide a protective shield means for shipping containers having radioactive material therein wherein means is provided for automatically stopping and arresting the circulation of air within the container at a predetermined temperature.

Other objects and many attendant advantages of the invention will become more apparent when considered in connection with the specification and accompanying drawings, wherein:

FIG. 1 is a top perspective view illustrating a truck of the fiat bed type having the apparatus of the present invention mounted thereon,

FIG. 2 is a top perspective view illustrating the manner in which the shield means of the present invention is lowered into place over a container;

FIG. 3 is an elevation view illustrating the shield means in operative position;

FIG. 4 is a top view of the structure shown in FIG. 3;

FIG. 5 is a sectional view taken substantially along line 55 of FIG. 3 looking in the direction of the arrows;

FIG. 6 is a sectional view taken substantially along line 66 of FIG. 3 looking in the direction of the arrows;

FIG. 7 is a sectional view taken substantially along line 77 of FIG. 5 looking in the direction of the arrows;

FIG. 8 is a sectional view taken substantially along line 3-8 of FIG. 3 looking in the direction of the arrows;

FIG. 9 is a sectional view taken substantially along line 9-9 of FIG. looking in the direction of the arrows;

FIG. 10 is a top perspective view with certain parts shown in spaced relationship and illustrating the framework of the present invention;

FIG. 11 is a sectional view through a typical insulated wall portion of the invention;

FIG. 12 is an elevational view partly broken away illustrating the modification of the present invention;

FIG. 13 is a sectional view taken substantially along line 1313 of FIG. 12 looking in the direction of the arrows;

FIG. 14 is an enlarged view of one of the air inlet means of the structure shown in FIG. 12;

FIG. 15 is a sectional view taken substantially along line 1515 of FIG. 14 looking in the direction of the arrows;

FIG. 16 is a sectional view taken substantially along line 1616 of FIG. 14 looking in the direction of the arrows;

FIG. 17 is a view illustrating a portion of FIG. 15 with the flow control means in a different operative position; and

FIG. 18 is an enlarged view of a portion of the structure shown in FIG. 15 illustrating the details of construction of the insulated wall structure.

Referring now to the drawings wherein like reference characters designate corresponding parts throughout the several views, there is shown in FIG. 1 a suitable truck for conveying the apparatus of the present invention, it being understood that any suitable vehicle such as a railway car or the like may be empolyed for this purpose. The truck is indicated generally by reference numeral 29 and includes a tractor portion 22 and a flat bed trailer portion 24 upon which is mounted a suitable base structure for supporting the apparatus.

The base structure is indicated generally by reference numeral 26 and includes a pair of longitudinally extend ing relatively heavy steel channel members 27 and 23 which are joined at the opposite ends thereof by end members 29 and 30. It is understood that any suitable means may be provided for securing the base structure 26 in operative position, and if desired these members may be either welded or bolted to the bed of the trailer portion.

A pair of

cross members

32 and 36 are provided between intermediate portions of

members

27 and 28,

members

32 and 36 also being in the form of channel members as shown in FIGURES 2, 3 and 4.

A pair of obliquely extending

channel members

33 and 34 extend between cross member 32 and

members

27 and 28 respectively. A similar pair of obliquely extending

channel members

37 and 38 extend between cross member 36 and

members

27 and 28 respectively. It will be understood that all of these members are rigidly interconnected with one another as by welding to provide a very strong and rigid base structure.

A first pair of spaced eye bolts 40 are fixedly secured to member 27, and a similar pair of eye bolts 42 are operatively connected with and extend upwardly from member 28. As seen particularly in FIG. 1, a pair of D- rings 46 are connected to the bed of the trailer portion along one side edge portion of the flat bed, and a similar pair of D-rings are secured to the opposite side portion of the flat bed. The eye bolts 49 and 42 as well as the attaching members 46 are employed for securing cables thereto which are in turn connected with the container mounted on the truck so as to retain the container in proper operative relationship as hereinafter more fully described.

The shipping contatiner employed with the present invention may be of the type as shown for example in copcndindg U.S. patent application Ser. No. 270,212, filed Apr. 3, 1963, now U.S. Patent No. 3,299,096. This shipping container is indicated generally by reference numeral 50, and as seen most clearly in FIGS. 2-7 inclusive includes a top portion 52 adapted to be closed by a closure 1 cans indicated generally by reference numeral 53, the body means of the container having longitudinally extending fins 54 extending outwardly from the outer surface thereof and being spaced from one another so as to assist in conducting away heat from the container. Four spaced reinforcing plates 56 extend from the outer surface of the body means to a base plate 60 which in turn is supported at the corners thereof by a plurality of pad members 62.

Trunnion portions 64 extend outwardly from diametrically opposite sides of the body means of the container, these trunnion portions extending between and being supported by plate members 66 and 63. A pressure relief means is indicated generally by reference numeral 70 and is connected with the interior of the container for relieving excess pressure should such develop therewithin. The pressure relief means is protected by a guard member 72 secured to the outer surface of the body means of the container and having a substantially U-shaped cross sectional configuration. The outlet portion of a drain conduit is indicated generally by reference numeral 74 and provides access to the interior of the container.

The shield means of the present invention is indicated generally by reference numeral 80, this shield means including a rigid open framework the construction of which may be most clearly understood from an inspection of FIGS. 5l0 inclusive. This framework includes a plurality of

top frame members

82, 84, 86, 83 and which are welded end to end to one another to provide a rigid upper rim for the framework. Each of these members is formed of an angle member having a generally L-shaped cross sectional configuration. A first pair of

elongated angle members

92 and 94 are secured and depend from upper rim member 88,

angle members

92 and 94 having

support plates

96 and 98 secured to the lower end thereof. A second pair of

members

160 and 102 are secured to and depend from member 86, member 190 comprising an angle member, and member 102 comprising an elongated fiat member, these two members having the base plates 1% and 104 secured to the lower ends thereof respectively. A third pair of elongated angle members 108 and 110 are secured to and depend from member 82, members 108 and 110 having support plates 112 and 114 respectively secured to the lower ends thereof. A fourth pair of depending members 116 and 118 also comprise angle members and are secured to member 82, these latter angle members also having suitable support plates secured to the lower ends thereof. It will be apparent that the over-all rigid frame structure is supported at four spaced points by the support plates secured to the lower ends of the aforementioned elongated depending members.

As seen most clearly in FIGS. 5 and 8, a first support plate 120 is supported by member 102 and extends in the space between members and 102, suitable spacer members being connected between

members

100 and 102 along the length thereof to retain them in the proper spaced relationship.

Similar support plates

122, 124 and 126 are supported by

members

94, and 118 respectively, each of these support plates extending within the space between the associated elongated members, it being understood that in each case the pairs of elongated depending members are held in spaced relationship by suitable spacer members extending therebetween at spaced portions along the length the eof.

A pair of

cross members

130 and 132 are provided, these members being disposed substantially normally to one another and intersecting one another as seen in FIG. 10 for example.

Members

130 and 132 each comprise channel members, the opposite ends of member 130 being suitably secured as by welding to the upper ends of plates 122 and 126, while the opposite ends of member 132 are suitably seemed as by welding to the upper ends of plates and 124. A small plate 134 which is of substantially square configuration is suitably secured as by welding to the intersecting portions of cross members and 132 to rigidify this central portion thereof.

An inner rim means indicated by reference numeral 156 is of generally annular configuration and has a substantially L-shaped cross section. Portion 136 may comprise a single member or may be made up of separate sections rigidly secured together if desired. The inner rim means 136 is supported on the upper portions of

cross members

130 and 132 and is rigidly secured thereto as by welding. Four spaced blocks 138 are secured to the inner surface of means 136 and to the upper surfaces of

members

130 and 132, each of these blocks having a threaded opening formed therein which is adapted to receive removable eye bolts indicated by reference numerals 140 in FIGS. 2, 3 and 4 of the drawings.

A first pair of elongated angle members and 152 have the opposite ends thereof bolted to the

support plates

120 and 124 respectively while a second pair of similar cross angle members 154 and 156 have the opposite ends thereof bolted to the support plates 122 and 126, angle members 154 and 156 extending substantially perpendicular to

members

150 and 152, these angle members being interconnected with one another at the central portions thereof as will be apparent.

Three spaced

annular members

160, 162 and 164 which may be termed thermal washers are provided, member 160 being supported on the upper edge of

angle members

150 and 154 and suitably secured thereto as by welding, member 162 being supported between

angle member

150, 152 and angle members 154 and 156 and suitably secured thereto as by welding, and member 164 being secured to the lower edge portions of angle members 152 and 156 and fixed thereto as by welding.

Each of these

annular members

160, 162 and 164 is coated with a suitable material such as intumescent paint which is adapted to intumesce at approximately 350 F. In other Words, when this temperature is reached, the paint will expand and swell so as to fill the space between the washers and between the adjacent components so as to block off the annular flow passage defined between the spaced washers and the adjacent components to prevent the circulation of air through the interior of the shield means.

A pair of angle members and 172 are provided, these angle members being disposed at substantially right angles to one another. The first angle member 170 has the opposite ends thereof suitably secured to the support plates 12th and 124 as by welding, and the other intersecting angle member 172 has the opposite ends thereof suitably secured as by welding to the other pair of support plates 122 and 126, angle members 170 and 172 of course being interconnected rigidly with one another at the central portions thereof.

Angle members 1'70 and 172 serve to support a disclike bafl'le means 174 which is fixedly secured to the upper surfaces of members 17% and 172. It will be noted partieularly as seen in FIG. 7 that

plates

120 and 124 are provided with cutout portions 120 and 124' which are adapted to provide a clearance with the upper portion 52 of the container disposed within the shield means. It should be understood that the other support plates 122 and 126 are provided with similar cutout portions in order to provide the desired clearance with the container means.

As seen most clearly in FIG. 10, a generally arcuate angle member 189 extends between the vertically extending

elongated members

92 and 110, the angle member 1841 including a central portion indicated by a reference numeral 183. A pair of

angle members

182 and 184 extend vertically between member and member 50, the opposite ends of

members

182 and 184 being rigidly secured to the respective members as by welding. A cross angle member 186 has the opposite ends thereof rigidly secured to an intermediate portion of the vertically extending

angle members

182 and 134. Four nuts are rigidly affixed to the inner surface of

members

182 and 184 and are aligned with openings provided through these members for receiving attaching bolts as hereinafter described.

Portions

182, 184, 186 and 188 define an access opening for gaining access to the interior of the shield means. A removable portion framework is indicated generally by reference numeral 200 and includes opposite

side angle members

202 and 204 which are rigidly interconnected with opposite

end angle members

206 and 208. These various interconnected members provide a boxlike framework, and four hollow cylindrical members 216 are provided at the inner corners of this framework and are aligned with openings provided in the associated members whereby attaching bolts may be extended through these cylindrical members 210 of the framework 200.

As seen most clearly in FIG. 9, the removable portion is shown in operative position wherein attaching bolts 212 extend through the cylindrical portions 210 and through the aligned openings and are threaded into the nuts 190 which are fixed to the inner surfaces of

members

182 and 184 as aforedescribed. It is apparent that these attaching bolts 212 provide a means for rigidly securing the removable portion in operative position, yet at the same time enable this removable portion to be removed when so desired.

As seen in FIG. 10, a lower areuate framework portion 220 extends between the vertically elongated

members

92 and 110. Member 221) may be formed as a single angle member or may be composed of a plurality of individual sections as desired. It is of course apparent that the portion 180 may similarly be formed of a plurality of interconnecting portions if so desired. A pair of

framework members

222 and 224 which may be of partially arcuate configuration extend between the vertically elongated members 100 and 116, and these frame members of course have the opposite end portions thereof rigidly attached to the vertically extending associated members. The

framework portions

222 and 224 may also be comprised of single channel members or a plurality of sections rigidly interconnected with one another as desired.

The framework is provided with trunnion receiving portions and openings at opposite sides thereof, and the structure at opposite sides of the framework is identical in this regard and accordingly the same reference numerals are employed for identifying the same components at opposite sides of the shield means.

Again referring particularly to FIG. 10, a channel member 231) of substantially U-shaped cross sectional configuration extends between vertically

elongated members

94 and 102, channel member 230 having three spaced nuts 232 secured to the inner surface thereof and aligned with openings formed through the leg portion of the channel member. A pair of angle members 236 and 238 depend from the undersurface of channel member 231] and are rigidly afiixed thereto.

An angle member 241} extends between member 94 and member 236, and a similar angle member 242 extends between member 102 and member 238. A generally outwardly extending U-shaped member 244 is also an angle means in cross section configuration and has three spaced members 246 secured thereto which are also seen in FIG. 6, members 246 having a generally cylindrical shank portion extending upwardly from member 244 and also including an enlarged head portion which is welded or otherwise rigidly secured to the undersurface of member 244 to hold members 246 permanent ly in the operative position shown.

An angle member 248 extends between members 94 and the lowermost end of member 236, and a similar angle member 250 extends between member 102 and the lowermost portion of member 238. A member 252 is of generally the same configuration as member 244 and comprises an angle means in cross sectional configuration.

Referring particularly to FIGS. 6 and 10, a removaable cover means for the trunnion receiving openings in the framework is indicated generally by reference numeral 260. This cover means includes a bottom member 262 having three spaced openings formed therein and having three cylindrical socket portions 264 aligned with these openings. These socket portions 264 receive the upwardly extending cylindrical shank portions of members 246 as seen most clearly in FIG. 6 whereby the removable cover means is accurately guided into operative position and held in the proper relationship on the framework, it being understood that each of the members 246 fits within one of the members 264.

The cover means also includes opposite side members 266 and 261? which are secured at one end thereof to member 262 and have the opposite ends thereof rigidly secured to end top members 276 and 272. Members 2 70 and 272 are connected between the forward top member 274 and a rear top member 276 which may be of arcuate shape at one end thereof so as to conform to the outer arcuate shape of one end portion of the channel member 230 of the framework.

Three spaced cylindrical members 286 are connected between members 274 and 276 and are aligned with openings provided in members 274 and 276 whereby attaching bolts may be passed therethrough for securing the cover means in position on the framework as hereinafter explained.

A pair of bafile members 282 are of generally L- shaped cross sectional configuration and are cut away to provide a reduced portion 284 to provide a clearance for the cable means attached to the trunnions of the container, the remaining portions of the bafiles 282 serving to protect a container within the shield means from direct radiation from a heat source disposed externally of the shield means.

In mounting the cover means 260 in operative position, members 264 are moved into position to receive the members 246, and then attaching bolts 286 as seen in FIG. 6 are passed through the cylindrical members 280 and are threaded into the nuts 232 which are rigidly secured to the inner surface of channel member 230. It is apparent that these attaching bolts serve to firmly secure the removable cover means in operative position during shipping, and yet at the same time permit the cover means to be readily removed when desired.

As seen particularly in FIG. 1, the cable means for holding the container in operative position includes a first pair of cables 290 connected between the eye bolts 42 and the trunnion on one side of the container, and a second pair of cables 292 are connected between the attaching members 46 and the trunnion at one side of the container. These cables of course extend through the cutout portions 284 of the baffle means on the removable cover means 260 as described hereinabove. A second pair of cables 294 extend between the eye bolts 49 and the other trunnion of the container, while another pair of cables 296 extend between the attaching members 46 at the opposite side of the bed of the truck and the trunnion at the said opposite side of the container means.

It will be recognized from the foregoing discussion that the open framework of the present invention as well as the removable portion for the access opening and the removable covers for the trunnion openings and also the disc-like bafile 174 must of necessity include wall portions of substantial thickness which have a heat insulating construction so as to protect the container within the shield means. These heat insulating wall portions are of course mounted between the rigid structural members of the framework and between the rigid members of the other aforementioned components. The wall portions may be varied in construction, and a typical form of the wall construction is illustrated in FIG. 11. As seen in this figure, a body of insulating material is in dicated generally by reference numeral 300. This insulating material may be selected from various thermal insulation products, and for example may be made of reacted calcium silicates containing no glass. A typical example of this construction is a product identified by the trademark Kaylo, manufactured by the Owens- Illinois Glass Company, Toledo, Ohio. This particular material has no inherent strength, and accordingly it in itself would tend to break off and be lost. Accordingly, this insulating material is mounted between two sheets of expanded metal indicated by reference numerals 302 and 304. In order to provide over-all strength to the wall section, the insulating material is placed under slight compression by providing a plurality of studs 306 which are fixed at one end 308 thereof as by welding to the expanded metal sheet. These studs are provided with threads at the opposite end thereof, and nuts 310 are threaded thereon to place the insulating material under compression. A compressible member 312 which may be formed of rubber or the like is provided between the sheet of expanded metal 302 and an outer sheet 314 of a suitable heat reflective substance such as aluminum or the like. This outer heat reflecting surface serves to pro tect the shield means from heat radiation.

As shown, a structural member is indicated by reference numeral 302, this structural member being typical of one of the frame members of the rigid framework. Another sheet of aluminum is indicated by reference numeral 322, an angle member 324 spanning the joint between adjacent sheets of

aluminum

314 and 322. The angle member as well as the sheet 322 is held in operative position by self-tapping screws 326 which are screwed into the operative position shown.

The inner and outer surfaces of the insulating wall portions immediately inwardly of the outer sheets of aluminum are covered with a waterproof mastic substance before the aluminum is installed in operative position in order to waterproof the entire shield means so that the shield means is adapted to withstand normal Weather conditions which will be encountered during shipment of containers from place to place.

As an alternative, rather than utilizing a thermal insulating substance which must be placed under compression, a foaming type substance may be utilized which may be foamed into position between sheets of metal and then allowed to fill the space and to achieve the desired completed structure.

Referring again to FIGS. 5 through 9 inclusive, the various heat insulating Wall portions are shown in position on the framework members, and in each case the heat insulating wall portions have been given similar reference numerals in order to simplify the description. Each of these heat insulating wall portions is indicated by inner and outer sheets of expanded metal which are indicated generally

b reference numerals

330 and 332 respectively and whi have the outer peripheries thereof fixed to the associated structural members as by welding or the like. A body of insulating material is indicated by reference numeral 336 and as being sandwiched between the outer and inner expanded

metal wall portions

330 and 332. In these figures, the bolts for applying compression to the insulating material have been eliminated for the sake of clarity. It will be realized that these bolts may be employed if required, or on the other hand, a material may be utilized which does not require the necessity of providing bolts for compressing the insulating material. In addition, the outer sheet of heat reflective material is indicated by reference numeral 338 on each of the heat insulating wall portions.

It should also be noted that the removable portion 200 for the access opening as well as the removable cover means for the trunnion openings are provided with similar insulating Wall portions, and the construction of the battle means 174 is also of a similar construction wherein the same reference numerals have been applied to corresponding members.

Referring now to FIG. 2, the manner in which the shield means is mounted in operative position may be most clearly understood. As seen in this figure, the container 50 has first been lowered into operative position on the base structure mounted on the bed of the truck trailer. The shield means is then lifted by providing a cylindrical member 350 which is inserted through the eye bolts 140, a hoisting hook 352 engaging member 350 for lifting and lowering the shield means.

The lower side wall portions of the shield means are provided with four spaced cutouts 356 which are adapted to receive the reinforcing plates 56 of the container. These cutouts may also be seen in FIG. 3 of the drawings.

It is apparent that the shield means may be mounted in operative position in a very simple and expeditious manner and merely by lowering it into the operative position about the container. The heat insulating wall portions will effectively protect the container, and the spacing of the lowermost portions of the side walls above the support or foot portions on the vertically extending elongated members provides an air inlet means whereby the air may circulate within the shield means and about the container means and thence through the annular flow space defined between the

thermal washers

160, 162 and 164 and finally outwardly through the upper outlet opening of the shield means. Such circulation will of course be cut off if the thermal washers are exposed to a heat within the range aforementioned which causes intumescence of the coating on these washers.

Referring now to FIGS. 12 through 18 inclusive, a modification of the invention is illustrated which is also adapted to serve as a means for shipping radioactive fuel elements. In this modification, a base structure adapted to rest upon a truck, railway car or the like includes a rectangular base portion comprising a pair of longitudinally extending elongated frame members 4-06 which have rigid end frame members 4-02 connected between opposite ends thereof. Small plates 4G4 and 406 are secured to the central portions of the opposite end wall portions 46.2 and have holes 404' and 406' respectively formed therein to assist in handling the base structure.

A forward pair of trunnion support members 416 are seemed to and extend upwardly from the opposite frame members 4th), and a second pair of rear trunnion support members 412 are mounted on spaced portions of the frame members 406. Each of these trunnion support members is provided with a recess adapted to receive trunnion portions formed on an associated container.

Members

420 and 422 are also secured to and extend upwardly from the frame members 4%,

members

420 and 422 being provided with suitable elongated openings 42% and 422 through which suitable means may be engaged when it is desired to lift or lower the base portion.

The container employed in this modification is illustrated generally by reference numeral 426, the container having a closure means 428 formed at one end thereof. The container also includes outwardly extending trunnion portions 430 mounted at spaced parts thereof and adapted to fit within and be supported by the trunnion supports 410 and 412 previously described. The outer surface of the container is also provided with spaced fins 432 to assist in conducting heat away from the container.

It will be noted that when the container is in its operative supported position as seen particularly in FIG. 12, it forms a slight oblique angle with respect to the base members 466 and 412 which may have the long axes thereof in a substantially horizontal position during normal shipping procedures.

The shield of this modification is indicated generally by reference numeral 446 and includes a main body portion 442 which is of generally U-shaped configuration as seen in FIG. 13, the lower portions of this main body portion being adapted to fit about the opposite longitudinally extending base members 400. The shield means also includes a forward wall portion 444 and a rear wall portion 4467 A plurality of air inlet means are indicated generally by reference numeral 450, these air inlet means being spaced about the walls of the shield means in the lower portions thereof. A plurality of air outlet means are indicated by reference numerals 452, these air outlet means being disposed at the upper portion of the shield means.

Referring now particularly to FIGS. 14-16 inclusive, a portion of the insulated wall structure is indicated generally by reference numeral 460, and one of the air inlet means 450 is illustrated in detail. This air inlet means 450 is supported by a pair of opposite

side angle members

462 and 470 which serve to support the edge portions of the insulated wall structure defining the air inlet opening. The first angle member 462 supports an angle member 464 of the air inlet means, member 464 being operatively secured in position by a plurality of screws 466 extending through and being threaded within aligned openings formed in

members

462 and 464. Screws 466 also serve to clamp a sheet of expanded metal 468 in operative position so as to cover the air inlet opening and to prevent the entry thereinto of undesired foreign matter.

The other angle member 470 serves to support an angle t member 472 of the air inlet means, member 472 being held in position by a plurality of screws 474 which also serve to clamp the sheet of expanded metal 468 in operative position. A pair of end angle members 486 and 482 of a construction similar to

angle members

464 and 472 are provided to define the remaining portions of the substantially rectangular air inlet opening. It will be recognized that while the air inlet means is illustrated as being rectangular, it can be of various configurations as desired.

A plurality of shutter or valve members, shown as being five in number, are indicated by reference numerals 490, these shutter members being pivotally supported by a pin 492 at one end thereof which is supported by angle member 464, the shutter members being pivotally supported at the opposite end thereof by a member 494 supported by the angle member 472. It is apparent that the shutter members are accordingly mounted for pivotal movement about an axis extending through the center of members 492 and 4%.

As seen particularly in FIG. 17, each of the shutter members is provided with an opening 496 through one side thereof, and angle member 472 is provided with five spaced openings 498. As seen in FIGS. 14-16 inclusive, low melting alloy shear pins 500 are shown as being disposed within

openings

496 and 498 which are aligned with one another when the shutters are held in their open position as shown in these figures. These shear pins 500 may be formed of different materials in accordance with the desired melting point at which the shear pins are adapted to melt and allow the shutter members to move into their closed position. For example, the pins 500 may be formed of Woods metal having a melting point of approximately 158 F. and having a composition by weight of 50 Bi, 25 Pb, 12.5 Sn, and 12.5 Cd. Pins 590 may also be formed of Tin Eutectic having a melting point of 293 F. and consisting essentially by weight of 50 Sn, 32 Pb and 18 Cd. Pins 5% may also be formed of bismuth solder having a melting point of approximately 231 F. and consisting essentially by weight of 40 Bi, 40 Pb and 20 Sn.

The shutter or valve members 490 are normally urged toward the closed position by spring members 516 having a first arm portion 512 fitted within a suitable opening provided in channel member 464. An opposite arm 514 of each of the spring members is operatively connected with the shutter or valve members 4% by fitting through a pressed out portion 516. It will be apparent that the springs are so mounted as to normally urge the members 490 to pivot into the closed position illustrated in FIG. 17 after the shear pins have melted and enabled the spring members to move the members 490 to this position.

It is apparent that by selecting the shear pins of a suitable material, the temperature at which the members 4-91 will close off the air inlets may be accurately determined. It is further evident that when members 490 move into the position shown in FIG. 7, the circulation of air within the shield means and about the container will be arrested.

Referring particularly to FIG. 18, the details of construction of the insulated wall portion of this form of the apparatus are illustrated. As shown in this figure, the insulated wall structure comprises a plurality of sheets 520 of a suitable material such as light gauge stainless steel, these sheets being disposed in substantial parallelism with one another. The outermost sheet 522 is formed of a ma erial which will provide maximum reflectance of heat energy and may for example comprise aluminum.

The

sheets

520 and 522 are maintained in spaced rela tionship with one another so as to provide insulating air spaces therebetween. As illustrated in the drawing, this spacer means may comprise integral embossments or corrugations indicated by reference numerals 520' and 522 formed on the

sheets

520 and 522 respectively.

This arrangement provides a lightweight relatively rugged structure which at the same time provides good heat insulating qualities.

The outlet means 452 as seen in FIGS. 12 and 13 may simply comprise cylindrical portions of expanded metal having a suitable dome-shaped cover thereover. These outlet portions may also be provided with means for arresting the circulation of air within the shield means. Either the inlet means or outlet means or both may be provided with flow control means if desired. The expanded metal portions of the outlet means 452 may for example be coated with intumescent paint in order to shut off the circulation of air if so desired.

It is apparent from the foregoing that there is provided according to the present invention a new and novel protective shields means and more particularly a fire shield for shipping containers having radioactive material therein. It is apparent that the construction according to the various modifications of the present invention will protect and enclose the container not only from external fires but also will serve to protect the container from solar radiation and from accidental damage due to physical bumping or striking of the container as well as further preventing dirt or other foreign material from accumulating on the container. The shield means incorporates baffies to prevent direct radiation from an external heat source from hitting the container surface. Air is permitted to circulate around the container during normal shipment procedures so as to carry decay heat away from the container, and flow control means is provided for automatically arresting circulating of the air within the shield means at a certain predetermined temperature so as to prevent the undesired effect of circulating hot air around the container. This flow control means may take the form either of intumescent paint or mechanically operated shutter or valve means as desired.

As this invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, the present embodiment is therefore illustrative and not restrictive, and since the scope of the invention is defined by the appended claims, all changes that fall within the metes and bounds of the claims or that form their functional as well as conjointly cooperative equivalents are therefore intended to be embraced by those claims.

We claim:

1. Protective shield means for containers having radioactive material therein comprising a hollow body means adapted to receive a container and be spaced therefrom so as to permit air flow about the container to convect heat away therefrom, said body means having wall portions formed of heat insulating material and disposed so as to shield and protect an enclosed container from a source of heat disposed outwardly of the body means, said body means having air inlet means disposed at the lower portion of the body means for permitting the entry of air into the interior of the lower portion of the body means, the body means having air outlet means formed therein at the upper portion thereof to permit heated air to pass outwardly of the body means, and air flow control means supported by the body means, said air flow control means being normally open to permit circulation of air into the air inlet means, through the interior of the body means and outwardly through the air outlet means, and temperature responsive means for closing the air flow control means so as to arrest the circulation of air through the body means when the air adjacent the temperature responsive means reaches a predetermined elevated temperature.

2. Protective shield means for shipping containers having radioactive material therein comprising a body means having a hollow cavity formed therein for receiving a container, said body means including wall portions formed of a heat insulating construction so as to protect and shield a container therewithin from a source of heat disposed externally of the body means, the wall portions being normally spaced from an enclosed container so as to permit free air circulation within the body means and about an enclosed container, said body means defining air inlet means at the lower portion of the body means for permitting air to enter the lower portion of the body means, said body means also defining air outlet means formed at the upper portion of the body means to permit air to escape from the body means at said upper portion thereof, and air flow control means disposed adjacent one of said means for permitting fiow of air between the interior of the body means and the surrounding atmosphere, said air flow control means being normally open to permit free air flow through the body means, and temperature responsive means for automatically closing the air flow control means when the air adjacent the temperature responsive means reaches a predetermined elevated temperature so as to arrest the free circulation of flow through the body means and to prevent any further air flow therethrough.

3. Protective shield means for containers having radioactive material therein comprising a body means having a cavity therewithin for receiving a container with the body means spaced from the major portions of the container to permit free air flow about the container, said body means having wall portions formed of heat insulating material so as to shield and protect a container within the shield means from a source of heat disposed externally of the body means, said body means defining air inlet means at the lower portion of the body means to allow air to enter the lower portion of the body means and to circulate within the body means, the body means also defining an outlet means at the upper portion thereof. air flow control means supported adjacent said air outlet means and including members having intumescent material disposed thereon which is adapted to intumesc-e at a predetermined temperature so as to close off the air outlet means and to arrest circulation of air through the body means at such predetermined temperature.

4. Apparatus as defined in claim 3 wherein said air flow control means includes a plurality of annular members which are spaced from one another, said air outlet means comprising an annular flow space, said annular members being disposed within said annular fiow space, and the annular members being coated with intumescent paint which is adapted to swell up and fill the said annular flow space so as to positively prevent any further flow of air through the body means at said predetermined temperature.

5. Protective shield means for shipping containers having radioactive material therein comprising a body means including a relatively rigid open framework, said body means defining a central hollow cavity for receiving a container and the bottom portion of the body means being open so as to be lowered over a container, the body means including wall portions formed of heat insulating material supported on said framework, said wall portions being spaced from the lowermost supporting portion of the framework so as to define air inlet means at the lower portion of the body means through which air is adapted to enter and circulate within the body means, the body means including a central air outlet opening at the upper part thereof, the body means defining a substantially annular flow space for the circulation of air from the interior of the body means to the air outlet opening, air flow control means including a plurality of annular members adjacent said air outlet opening, said annular members having intumescent material disposed thereon which is adapted to swell up and close off said annular flow space at a predetermined temperature whereby the circulation of air is arrested.

6. Apparatus as defined in claim wherein said heat insulating wall portions include bodies of insulating material, said bodies of insulating material being sandwiched between sheets of metal and the bodies of insulating material being under compression between said sheets of metal, the wall portions having heat reflective surface.

7. Apparatus as defined in claim 5 wherein said body means includes openings for receiving trunnions formed on a container, the body means including removable cover means for covering the trunnion openings, said removable cover means including bafile portions for protecting the interior of the body means from heat radiation from the exterior of the body means.

8. A protective fire shield for shipping containers having radioactive material therein comprising a body means including a rigid open framework which is open at the bottom and which defines a hollow cavity therewithin so that the body means may be lowered over a container, the body means including wall portions of a heat insulating construction, said wall portions including bodies of insulating material, said bodies of insulating material being sandwiched between sheets of expanded metal and with the bodies of insulating material under compression, the heat insulated wall portions being supported on the open framework and held in position thereon, the framework including depending support portions for supporting the framework, said heat insulated wall portions terminating at a position spaced above said support portions so as to define air inlet means at the lower part of the body means for permitting the entry of air into the interior of the body means, said heat insulated wall portions including an outer surface formed of heat reflective material, said body means including a pair of openings for trunnion means formed on a container, a removable cover means for each of said trunnion openings, each of said cover means including bafiles for protecting the interior of the body means from heat radiation from the exterior of the body means, said body means defining an access opening for gaining access to the interior of the body means, a removable portion for closing said access opening, the body means including a central air outlet opening formed at the top thereof, the body means defining a substantially annular flow space to permit air to circulate through said flow space and outwardly through said air outlet opening, and air flow control means supported by said body means adjacent said air outlet opening, said air flow control means including a plurality of spaced annular members disposed within said annular flow space, each of said annular members being coated with intumescent paint which is adapted to intumesce at a predetermined temperature so as to close ofl said annular flow space and to arrest the circulation of air through the body means.

9. Protective shield means for containers having radioactive material therein comprising a body means having a hollow interior for receiving a container therewilhin and being normally spaced from the container so as to permit air flow thereabout, said body means including wall portions of heat insulating construction, the body means defining air inlet means in the lower portion of the body means and air outlet means in the upper portion of the body means, and air fiow control means for controlling the How of air through the body means, said air flow control means being normally open to permit free air flow and being adapted to close at a predetermined temperature to prevent such free air circulation within the body means, said air flow control means including a member normally held in an open position, and temperature responsive means for automatically moving the member to a closed position when the air adjacent the temperature responsive means reaches a predetermined elevated temperature.

10. Apparatus as defined in claim 9 wherein said air flow control means comprises a plurality of pivotally mounted members, resilient spring means normally urging said members toward a closed position, and means engaging said members for retaining them in open position until said predetermined temperature is reached.

11. Apparatus as defined in claim 10 wherein the means for holding the plurality of members in open position comprises a shear pin engaging each of said members, each of said shear pins being adapted to melt at said predetermined temperature so as to release the associated members and to permit them to move into closed position.

12. Apparatus as defined in claim 9 wherein said heat insulating wall construction includes a plurality of substantially parallel sheets of metallic material disposed closely adjacent one another, and means for spacing said sheets of material from one another so as to define air spaces of substantial thickness therebetween.

13. Apparatus as defined in claim 12 wherein said sheets of material are provided with integral embossments which serve as spacer means to retain the sheets of material in spaced relationship.

References Cited UNITED STATES PATENTS 1,459,318 6/1923 Birdsall 32 X 3,161,266 12/1964 Miller et al 250-108 X 3,249,507 5/1966 Gondoin et al 250-108 3,251,407 5/1966 Crosthwait 165-96 X ARCHIE R. BORCHELT, Primary Examiner.