Experience gained from the space nuclear rocket program (rover)

LA-10062-H History - , Experience Gained from the Space Nuclear Rocket Program (Rorer) ' For Reference Not to be taken from this room n IA\� !{} n� rnr;l(R\ o � �� �U@u u 'W:V� Los Alamos National L:at>oratory LosAlamos,Newtv1ex1CO 87545 An Affirmative'Action/Equal Opportunity Employer This work was supported by the Air Force Weapons Laboratory, Kirtland Air Force Base, Kirtland, New Mexico �- DISCLAIMER This report was prepared as an account of work sponsored by an agency of the United States Government Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof The views and opinions of authors expressed herein not necessarily state or reflect those of the United States Government or any agency thereof LA-10062-H History UC-33 Issued: May 1986 Experience Gained from the Space Nuclear Rocket Program (Rover) Daniel R Koenig L r n 'Q' � f& n0lf"n'hlt(5\ � LosAlamos National Laboratory ��� �Li@U Li Li�� LosAlamos,NewMexico87545 CONTENTS ABSTRACT I OVERV I EW II H I STORICAL PERSPECT I VES REACTOR DEVE LOPME NT III IV Ki w i - A B Ki wi-B and NRX C Phoeb u s D Pewee E Hucl ear Furnace , NF - •••••••••••••••••••••• •••••••••••••••••••• F Fuel Devel opment • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • A E ng i ne Tests B E ngi ne Des i gn Improvements C NERVA a nd Smal l E ng i ne De s i gn s D Component Devel opment E Testi ng Fa c i l i ti es • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • A F l i ght Engi ne B Space Power Generati o n C Dual -Mode Reactors SUMMARY • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • FUTURE D EVE LOPMENTS • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • A ENGI NE D EVE LOPMENT V VI • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 10 11 13 16 16 17 18 19 21 21 21 21 22 23 VI I ACK NOWL E DGME NTS VII I SUPPLEMENTAL B I BL IOGRAPH Y •••••••••••••••••••••••••• ••••••••••••••••• 24 REFERENC ES TAB LES • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • FI GURES • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 24 26 30 32 v E XPERIENCE GAINED FROM THE SPACE NUCLEAR ROCK ET PROGRAM ( ROVER ) by Dan i e l R Koe n i g AB STRACT In 1955 the U n i ted States i ni ti ated Proj ect Rover to deve l o p a nucl ear rocke t e ngi ne for use i n defense systems and space expl oration As part of that proj ect, Lo s Al amos devel oped a seri e s of reactor des i gns and hi gh-temperature fuel s Three h i gh-power reactor seri es c u l mi nated in P hoebu s , the most powerful reactor ever bui l t , wi th a peak power l evel o f 4080 MW Two l ow-power reac tors served as tes t beds for e val uation of hi gh- temperature fuel s and other components for ful l - s i ze nucl ear rocket reactor s Lo s Al amo s devel oped a nd tested several fuel s , i ncl udi ng a fuel s i sti ng o f highly enriched uc2 particles, coated wi th pyrolyti c graph i te , and i mbedded in a graph i te ma tri x and a compos i te fuel that formed a conti nuous web of uran i um zi rconi um carbi de th roughou t the graphi te matri x The program produced the desi gn of the Smal l Engi ne , wi th a possi bl e l i fetime of several hours i n space The Astronucl ear Laboratory of the Westi nghouse E l ectr i c Corporati o n , havi ng re­ spons i b i l i ty for devel op i ng a pro totype reactor based on the L o s Al amos des i gn, con­ ducted an extens i ve and succe s sful test seri e s that c u l mi nated wi th the NRX-6 reactor test that ran conti nuously for 60 mi nutes at des i gn power Aeroj et-General Corporati on , prime contractor for devel opment of a compl ete rocket engine , developed two engi ne test seri e s , the NRX/EST and the XE ' , to eval uate startu p , fu l l -power, and shutdown cond i ti o n s i n a vari ety of a l t i tude and space simu­ l ati o n s The Un i ted States termi nated Proj ect Rover i n J a nuary a t the poi nt of fl i ght engi ne devel opment, but testi ng had i ndi cated no technol og i cal barriers to a succes s­ ful fl i ght system Conceptual stud i e s al so i ndicated that nucl ear rocket eng i ne tech­ nol ogy coul d be appl i ed to the generati on of el ectri c power i n spac e I OVERVIEW fi nal ma s s In 955 the Un i ted States embarked on a pro­ gram to devel op a nucl ear rocket eng i n e The program , k nown as Proj ect Rover, wa s i ni ti ated a t Lo s Al amos Nati onal Laboratory , then cal l ed Lo s Al amos Sc i enti f i c Laborato ry The concept to be hy drogen-c ool ed pursued was a sol i d-c ore , at earth-e scape veloc i ty , a s exempli ­ fied i n Fi g In J anuary 197 , after a total e xpendi ture of approximately one and a hal f bi l ­ l ion dol l ar s , tec h n i cal the succe s s ) program wa s eng i ne s changed several of the pro gram space The because a of The expec ted appl i cati on for nucl ear rocket a in termi nated j udged changi ng national pri ori ti e s reactor i n which the ex i ti ng gas expanded through rocket nozzl e and d i sch a rged ( al though times duri ng the course At f i r s t , nucl ear rockets were moti vati o n for the devel opment of such a rocket consi dered a potenti al back-up for i nterconti nen­ engi ne was that it coul d pro v i de about twice the l) spec i fic impul se ( of the best chemical tal rockets and , corre spondi ngly , fl i ght factor of i n a reducti on by a the rati o of ta ke-off ma s s to bal l i sti c m i s si l e ( ICBM) propul s i o n Later they were menti oned a s a second stage for l u nar A more durabl e possi bi l i ty wa s the i r use in manned Ma rs fli ght s After pl a n s for manned Mar s fl i ghts were abandoned as too amb i ti ou s , the La boratory of the Westi nghouse E l ectri c Corpora­ fi nal t i on pos s i bi l i ty advocated for nuc l ear e ng i ne s wa s ea rth orb i t-to-orbi t tran sfer ( WA NL ) , the pri nc i pal s ubcontractor to devel op the NERVA nucl ear reac tor When anal y s i s showed chemical rockets to be A seri e s of reactors and engi nes was tes ted more economical for orbi t-to-orb i t mi s s i o n s , the at the Nucl ear Rocket Devel opment Stati on ( NRDS ) need for a nuc l ear engi n e for rocket vehi c l e ap­ i n the test si te at J ackas s Fl ats i n Nevada where p l i cation ( NERVA ) evaporate d , and the program was maj or testi ng fac i l i ti es were bui l t for the Rover cancel ed before achi evement of a fl i ght demo n­ program ( Fi g ) s trati on The des i gn and the objecti ves of the NERVA are shown i n Fi g Most o f the des i gn objecti ves were met or exceeded duri ng the course NERVA s l i ghtly D u ri ng d i sas sembly faci l i ty and two testi ng faci l i ti e s for the resea rch a n d engi ne reacto r s in Fi g pressurized, operation, is attached l i qu i d the hydrogen hydrogen engi n e by a turbopump to is fed a tan k to the The hi gh-pressure fl ui d fi rst regenerati vel y cool s the nozzl e and the The tes t­ nuc ear rocket reactors i s ; ng program for the summari zed i n Fi g o f the pro gram The These i ncl uded an a ssemb l y and It was i ni ti ated wi th a fami ly of research reactors named K i wi fl i ghtl e s s b i rd of New Zeal and) ( for the The program obj ecti ves were fi rst to demon s trate the proof of pri nc i p l e , then to establ i sh technol ogy and devel op the bas i c sound desi gn reactor c oncept s reactor refl ector as shown i n Fi g 3, then passes These reactors were the fi rst t o demon s trate the through the reactor core u se of h i gh- temperature fuel s and to operate wi th No t shown in Fi g i s a paral l el cool ant c i rc u i t to cool the c o re - s u p­ l i qu i d hydroge n p ort is nated wi th the K i wi -B4E reactor, which operated heated suffi ci entl y to dri ve the turbopump befo re for 1 mi n at a cool ant exi t temperature above the cool ant rej o i n s the ma i n fl ow at the reactor 890 K and for 95 s at 2005 K and a power l evel t i e rods ; i nl et in the c i rc u i t the The core conta i ns sol id together by cool ant hexagonal ateral fuel e l ements banded support spri n g s Long i tudinal hol e s i n the fuel el ements provi de cool ant channel s for the hy drogen propel ­ of 940 MW The K i wi testi ng seri e s cul m i ­ These tests l ed to the Nuc l ea r Reactor Experi ment ( NRX) seri e s o f devel opmental reacto r s The i r goal was to demons trate a spe­ c i f i c i mpul se of 760 s ( 7450 m/ s ) for 60 mi n at a l an t , whi ch i s heated to 2400-2 700 K and fi nal l y thrust l evel of 245 kN ( 5 000 l b ) i n a 100-MW expanded through a thru st nozzl e reactor in the Rotati ng drums These objecti ves were exceeded i n the refl ector contai n i ng neutron absorber l ast tes t of provi de reacti v i ty control of the whi ch operated f o r 62 m i n at 100 MW a n d a tem­ neutron energy perature o f 2200 K , wi th only an $0 1 reacti v i ty materi al reacto r, wh i ch has an epi therma l spectrum The aim des i gn i ng of the Rover a nd demonstrati ng program , a rocket seri e s , the NRX-6 reactor , oss A nother s e r i e s of research reacto r s , cal l ed be s i d e s practi cal that P h oebu s , was devel oped wi th obj ecti ves i mpul se to 825 s , to i n­ engi ne , wa s to achi eve the hi ghest-po s s i bl e pro­ crea se the spec i f i c i ncrea s e p el l ant temperature ( s p ec i fic i mpul se i s propor­ t h e power den s i ty by 50%, a n d i ncrease t h e power tional to the square root of the temperatu re) for l evel to the range of 4000-5000 MW the b i l i ti e s were demo nstrated i n the P hoebus-lB and durati o n hour s ) of Thi s goal potenti a mi s s i on s ( severa i mp l i ed a s technol ogy Phoebu s-2A reactor s These capa­ The l atter , the most power­ ful reactor ever bui l t , ran for 12 m i n at 4000 MW devel opment program i n reactor fuel s Lo s Al amos Nati onal Laboratory was gi ven the and reached a peak power of 4080 MW The as t rol e of e stabl i shi ng a b a s i c reactor des i g n and two fami l i e s of re searc h reactors , Pewee a nd the o f l eadi ng the fuel s devel opment effort Nucl ea r Furnace ( NF ) , were tested only once each Other k ey p l ayers were the Aerojet-General Corp orati on, They the comp l ete respecti vel y , des i gned primari l y a s test beds to Astronucl ear d emonstrate the capabi l i ti e s of hi gher- temperature prime rocket contractor eng i ne to system, devel op and the the were l ower-power reactors, 500 and 44 MW fuel el ements and NF-1 Pewe e-1 ran for 40 mi n at 2555 K , operated for 109 mi n at an average For compari son, reactors is the pl otted mass versus of several power in Rover l evel in F i g 10 cool ant exi t temperature of 24 50 K I t was al s o recogn i zed that the design of a A n eng i ne devel opment test program was p a rt I ts objecti ves nucl ear rocket eng i ne coul d be al tered so as to were to tes t nonnucl ear system component s , deter­ provi de conti nuous statio n-keep i ng power for the m i ne system characteri s t i c s duri ng startup , ful l ­ mi s s i o n s power , and shutdown condi ti on s , eval uate control rocket systems were i ni ti ated i n concept s , and qual i fy the engi ne test- s tand oper­ one of the technol ogy demon s trati o n ati o n s in a downwa rd- f i ri ng confi gurat i o n wi th s i mul ated al ti tu de and space cond i ti on s These D e s i gn mode was second , a (4•5l stud i e s the normal c l osed-l oop , for s uch dual -mode -72 where propul s i on l ow-power and the el ectrical mod e The Rover program was termi nated i n J a nuary obj ecti ve s were met o r exceeded in the Nucl ear Reactor Experi ment/Engi ne System Test (N RX/EST ) 1973 at the poi nt of fl i ght engi ne devel opment a nd Ex peri mental Eng i ne ( XE ) programs A proto­ For a fl i ght sys tem , i t woul d be necessary to type fl i ght e ngi n e system, X E , consi sti ng o f a veri fy the fl i ght reactor and e ng i ne des i gn and f l i ght- type reactor wi th nonnucl ear fl i ght compo­ to perform l i fe and reproduc i bi l i ty testi ng nen t s , was tested i n a space-si mul ated envi ro n ­ there a re no apparent barri ers to a succes sful ment , performi ng some 28 s tarts a n d re start s n ucl ear rocket A chronol ogy o f the maj o r tests conducted duri ng the Ro ver program i s s h own i n F i g The technol ogy But devel oped duri ng the Rover program i s d i rectly appl i cabl e to the generati on The maj o r emph as i s of the reactor devel op­ of el ectri cal power i n space , e spec i al l y l a rge ment program was to i ncrease the reactor cool ant ( m ul timegawatt) bursts of el ectr i c a l power exi t temperature because the spec i f i c impul se i s an open-l oop converter system , one wou l d s i mpl y proport i onal to the square root o f that tempera­ repl ace the rocket nozzl e wi th a power conver s i on ture and to i ncrea se the operati ng time of the sy stem reactor wou l d be i nvo ved because The success of th i s part of the program i s i l l us trated i n F i g Cool ant exi t tempera­ Some redes i gn of the core For parameters the power converter, unl e s s it were a magnetohydrodynami c ( MHD ) sy s­ tures above 50 K and operati ng time over h tem , coul d not operate at the h i gh temperature of were demon s trated the Rover reacto r s The cumul ati ve time-a t-power The s ta rtup time for such a for the e nti re Rover program i s shown i n Fi g power pl ant woul d be The maj o r performance s ach i eved du ri ng the pro­ al l owabl e reactor gram are s ummari zed i n F i g about 83 K/s The Rover program was termi nated befo re a l rate of l i mi ted in part temperature by the change , However, a more severe i m i tati on i s in the propel l ant feed system , w h i ch requ i re s 60 s of the NERVA objecti ves coul d be demonstrated , i n approxi mately parti cul a r , before showi ng that a n e ngi ne coul d before chi 1 - down and to chi l l vari o u s pa rts of be operated for 10 h wi th up to 60 s tart i ng cyc l e s wi th a rel i abi l i ty of 99 bei ng pl aced on smal l e r engi nes for the orbi ta l A comprehensi ve de s i gn study wa s don e on a 367-MW , - kN the so-cal l ed Smal l ( 000-1 b) e ngi ne , ( •3) The total Engi n e mas s o f thi s e ng i ne was 2550 kg , and i ts overal l l ength was fol ded pos i ti o n m wi th the nozzl e The engi ne , In addi tion, pump cavi tati on there woul d b e time i mi tati o n s i mp osed by the power conve r s i o n sy s­ Toward the end o f the program, emphasi s was transfer mi s s i on the e ng i ne t o overcome ski rt together tem A cl osed- oop sys tem woul d re qui re further rede s i gn to i ncorp o rate the gas c i rc u l ators, and the core des i gn woul d have to be adj usted for the h i gher i nl et temperatures A s concerns dual el ectri cal - power modes ( a in a c onti nuo u s , wi th a hi gh-power mode ) much of the technol ogy and many l ow-power mode and a short-tenn, hy drogen tank c ontai n i ng nearly 13 000 kg of pro­ s tud i es pel l an t , coul d be carri ed on the space shuttl e appl i c abl e i f th e h i gh-power converter i s to be a devel oped under the Rover program a re gas system I I H I STORICAL PERSPECT I VES �- Thi s chapter summari zes the maj o r events i n the h i story o f the Rover program for the tes t s ummari e s wa s I nformati on obtai ned primari l y 945-1954 U SAF Sci enti f i c Adv i s o ry Boa rd s tudied the u se o f n ucl ear propul s i on for rocket systems The fi rst reactor test, K i wi - A , i s s uccessfu l l y at the Nevada Test The reactor operated for i nformati o n In 194 , at the suggesti o n of Theodore von the conducted (7 , ) S't i e at 70 MW and provi ded i mportant design and materi al s from Ref s 6-8 Karma n , 959 However, because o f a l ack of a c l ea r The fuel was hot enough ( 2683 K ) to mel t carbi de fuel e l ements The uo l oaded , p l ate-type fuel e l ements and was cool ed w i th abl e materi al s , and the techni cal di ffi cul t i e s o f tai ned a central devel o p i n g s uch a amount was recommende d no acti o n Neverthel e s s , paper stud i e s o f nucl ear rocket systems were pe rformed duri ng th i s ( , 10 l ga seou s of hy drogen The u ncoated , reactor core con­ i sl and of D o to reduce material req u i red fi s s i onabl e cri tical i ty Control the for rods were l ocated i n th i s i sl and period 960 �- 1954 Von Karman aga i n suggests tha t , i n v i ew o f Vi brati ons i n the damage i n the graph i te reactor empl oyed need for s uch systems , the shortage o f fi s s i on­ propul s i on system , part i c l e s core produced s tructural Ki wi - A ' i s tested for nearly m i n a t M W to demonstrate a n i mproved fuel -el ement the need f o r I CBMs and t h e good s upp l y o f fi s ­ desi g n s i onabl e materi al , the S c i enti fic Adv i sory Board uo - l oaded fuel e l ements c ontai ned i n graph i te modul e s The fuel el ement had four ax i al cool ant recons i de r nucl ear propul s i o n 955 October In a fi nal report , an ad hoc mends that because of the potenti al l y h i gh spe­ i mpulses wi th i n the rea l m of i mmedi ate achi evement from the nuclear rocket , substanti a l devel opment work s houl d b e started on t h e nucl ear No vember is L o s Al amos The n ucl ear rocket propul s i o n established and Laboratori e s u sed as Lawrence Projec t L i vermore Several conceptual desi g n s al ready had been at Rover Sci enti f i c nucl ear rocke t under study (ll) s h o rt , by a cyl i n dri cal , chemi cal vapor depo s i t i on ( C VD ) proces s August A Memorandum o f U nderstand i ng defi ni ng NASA and AEC respon s i bi l i ti e s and e s tab1 i shi ng a j o i nt nucl ear program offi ce , the S pace Nucl ear Propul s i o n O ffice, is s i gned Oc tober Kiwi - A3 reactor i s operated i n exc e s s o f m i n at 100 MW rocket system program reactor c h annel s coated w i th NbC c onvni ttee of the Sci enti f i c Adv i sory Board recom­ c i fi c The The fuel wa s s i mi l a r to that u sed i n the pre v i ous tes t earli e r tests, As wi th the c o re structural damage occurred , i ndicati ng that tensi l e s tructures shoul d be l oads avoi ded on graph i te Th i s experi ment But was the th i rd and l ast i n the K i wi - A seri e s of the concep t chosen to be pursued was a sol i d­ proo f-of-pri nc i p l e tests conducted by Los Al amo s core , hydrogen- c ool ed reactor that woul d expand The test seri e s demonstrated that thi s type o f hi gh-power-dens i ty gas through a rocket nozzl e March 18 The Atom i c Energy gram as a resul t o f budget restri c ti o n s and a Department of Defense reconvnendati on for a more of support cou l d be control l ed 1961 Commi s s i o n ( AEC) dec i de s t o phase Li vermore o u t o f the pro­ moderate l evel reactor and coul d heat hy drogen gas to high temperatures 1957 The l atter stenvned J u ne-J u l y General for I n du s tri al contractors , Aerojet­ the rocket engi ne and Westi nghouse E l ec tri c Corp orati o n l ected to p e rform for the reactor, the nucl ear rocket are se­ devel o p­ from the earl i e r- th an-a nti c i pated avai l abi l i ty of ment phase chemical program wa s i niti ate d at the Lockheed Corporati o n I CB M s , wh i ch reduced the devel opment o f n ucl ear propul s i o n u rgency for The reactor i n- f l i ght tests ( RI FT ) December new seri e s , reactors were refl ector nozzl e Kiwi - B lA reactor , is tested by desi gned control and Los for a fi rst o f a Al amo s 100 MW K iw i -B and regenerati vel y used cool ed Thi s test was the l ast to be run wi th gaseous hydrogen cool ant After 30 s of opera­ and fi nd sol utions for the severe s tructural dam­ age that was tests no power The p l anned maxi mum power of 300 MW was a s l i mi ted by the capabi l i ty of the nozzl e wi th ga seous hy drogen cool ant The core consi sted of l oaded fuel el ement s , seven cool ant channel s axial tube- c l addi ng The cyl i ndri cal NbC fuel coated uo havi ng by These tests were performed wi th gas­ n i trogen , were compl etel y f i rst to operate wi th l i qui d hydrogen �· The test n ated Fol l ow i ng a smooth , stabl e start , the run was termi nated after a few seconds were ejected from the reactor The core empl oyed Thi s was al so t h e fi r s t time K i wi-B4A , prototype tubes s The tes t was term i ­ a t ful l ruptured power when The core several consi sted of c l add i ng process August K i wi reactor, K i wi -B4E , the e i ghth and fi nal is tested by Los Al amos The reactor wa s operated for more than 12 mi n , the same type of fuel as Kiw i -BlA teste d the fi rst test at ful l uo -l oade d , 9-hol e , hexagonal fuel el ements wi th bores NbC coated by the tube­ at 900 MW when p o rti ons of several fuel el ements 30 Based o n resul t s i s c arri ed out wi th no i nd i cati o n after 60 ful l - l ength, a they i n el imi nati ng core a nuc l ear rocket reacto r abi l i ty o f the sy stem to s tart up and run u s i ng as s uccessful K i wi -B4D , desi gn power, nozzl e November and vi brations were made met i ts primary objecti ve o f demonstrati ng the i ntended hydroge n , a comp l etel y automati c start was accompl rshed for Kiwi - B lB reactor tes t i s the hy droge n and due to fl ow- i nduced v i brati on s of core vi brati o n 962 l i qu i d hel i um , demonstrated that the structural core damage was a el ements were conta i ne d i n graph i te modul e s September l to o f these tes ts a n d analyses, d e s i g n c h anges that about 66 cm l ong , proces s reactor referred t i cal to the power reactors except that they had eous run desi gnati on no fi s s i onabl e materi al a n d , therefore , produced sure vessel ach i eved , col d-fl ow reactor te sts that contai ned fuel e l ements i den­ t i o n , a hydrogen l eak i n the nozzl e a nd the pre s­ i nterface forced termi nati o n of the observed i n the previ ous The the fl i ght fi r st desi gn reactor, is The power run was termi nated at about w h i ch at nearly ful l power reactor operati on wa s mi n were smooth a nd s tabl e duration by wa s l i mi ted the avai l ab l e of The Its l i qu i d the 50% l evel when bri ght fl a shes in the exhaust hydrogen storage capac i ty O n September 10 , the ( c au sed by ejection of core materi al ) reactor was ran wi th i ncreasi ng frequency occurred Subsequentl y , i nten­ s i ve analyses and component testi ng were con­ power for mi n age The core consi sted for the fi rst time of el ements, channel s extruded , l oaded sti l l 9-hol e , hexagonal wi th were NbC coated uo • by the The fue l cool ant at nearly Thi s was the f i r s t demon stra­ hexagonal fuel el ements, time wi th uc p a rti c l e s l oaded for The the bore s coated by the tube- c l addi ng process September December The RIFT positi oned program is cancel l ed there is fi rst were N bC Measurements , at zero power, of the neutroni c i nterac ti on of two Kiwi 963 ful l The core consi sted of ful l -l ength , 9-hol e , tube-cl addi ng proce s s and t i o n of the reactor' s abi l i ty to re start ducted to determi ne the cause of the core dam­ ful l -l ength , re s tarted reactors adj acent to each other veri fy l i ttl e i nteraction and tha t , that from a I t was deci ded to rev i se the nucl ear rocket pro­ n ucl ear standpoi n t , nuc l ear rocket eng i ne s may be gram to p l ace empha s i s operated i n c l u sters s i mi l a r to chemi cal e ngi ne s on the devel opment of ground- b ased sys tems and defer the devel opment o f fl i ght systems reactor col d-fl ow tests NRX-A2 i s the fi rst NERVA tested at ful l power by Westi nghou s e 7) T h e reactor operated i n the range E l ec tri c ( 963-1 964 Several September 24 of Kiw i - B-type reactors a re carried o ut to determi ne the cause of hal f to ful l power ( 100 MW) for about m i n , a time l i mi ted by the avai l abl e hydrogen gas supp l y The tes t was succes sful and demons trated an equi val ent vacuum speci f i c i mpul se of 760 s The reactor wa s successful l y restarted on October 15 to i nvesti gate the margin of control i n the l ow-fl ow, l ow-power regime January 12 agai n at ful l power (-1100 MW ) J u ne for mi n to bri ng the total operati ng time at ful l power to hal f an hour The l i qu i d hydrogen capac i ty of the test faci l i ty w a s not tion at de s i g n power Kiwi -TNT ( Tran s i ent Nuc l ea r 967 i s succes sfu l l y compl eted by L o s Al amo s I n th i s fl i gh t safety tes t , a K i wi -B- type reactor wa s del i beratel y destroyed by pl aci ng it o n a 23 February Phoebus-lB is operated were at desi gn power of 500 MW The prima ry p u rp ose of of h i gher-power operati on affected the reacto r the reactor behav i or du ri ng a power excu r­ ( 12, 13) sion 23 N RX-A3 reactor i s operated for a bout m i n w i th about m i n at ful l power the test was The reactor was res ta rted o n May 20 and operated at fu l l for over 13 m i n It was restarted power aga i n on to detenni ne how the The fuel was the same as that u sed i n Phoebus-lA December N RX-A6 tes t exceeds the NERVA des i gn goal of 60 mi n at 100 MW i n a si ng l e run 968 The tes t was termi nated by a spuri o u s tri p from the turb i ne overspeed c i rc u i t for 45 mi n of wh ich 30 mi n , the maxi mum t i me p l anned , fast excursion to confi rm the analytical model s Apri l on s uffi c i ent to permi t 30 m i n of conti nuous opera­ 965 Test ) operated J u ne nucl ear 26 rocket Phoebu s-2A , reactor the ever m i n above 4000 MW most bui l t , powerful runs for The durati on o f the tes t i n the l ow- to w a s determi ned b y the avai l abl e cool ant supp l y medi um-power range to expl ore the l i mi ts of the Desi gned for 5000 MW , the te st was l i mi ted to 80% reactor operati ng map of ful l May 28 and operated for 45 mi n The total operati ng time power beca u se the al umi num segments o f of the reactor was 66 m i n wi th over 16 m i n at t h e pre s s ure vessel ful l power maturely J une T h e a i ms of Ph oebus-lA , the fi rst tes t of a new c l a s s of reacto r s , were to i ncreas e the speci f i c i mpul se , the power den s i ty i n the c l amp b a n d overheated pre­ The reactor was res ta rted on J u l y a nd operated at i ntermedi ate power l evel s December c e s sful l y Pewee reactor testi ng i s suc­ comp l ete d Pewee, des i gned to be a The tes t i s run suc­ smal l tes t-bed reacto r , set records i n power den­ c e s sful l y at ful l power ( 090 MW ) and core exit s i ty and temperature by operati ng at 503 MW for temperature ( 2370 K) 40 mi n at a cool ant ex i t temperature of 2550 K and a core average power densi ty of 2340 MW/m • core , and the power l evel was subsequentl y l i quid for 10 mi n damaged hydrogen supply when wa s The reactor the fac i l i ty's exhau sted Thi s Thi s power densi ty was 50 % greater than that re­ course of events was i n no way rel ated to a ny qui red for the 500-MW N E RVA reactor defect i n power den s i ty i n the fuel the ful l - l ength , reactor 9- ho l e , The core cons i sted hexagonal fuel of e l ements l oaded wi th coated uc parti c l e s The bores were NbC c l ad by the chemi cal vapor depo s i t i o n The N RX/EST , f i r s t N ERVA breadboard power pl ant, the i s operated du ri ng di fferent days for a total o f h and of which ( 100-1 200 MW ) greatest achi eved 28 mi n These by were time s a at were s i ng l e ful l by nucl ear power ful l X E ' , the fi rst down-fi ri ng prototype at 100 MW i s succe s sful l y operated The reactor was operated at vari o u s power evel s on di fferent days f o r a total of 1 mi n o f power operati on that i ncl uded 28 re­ s tarts Indi vi dual times were i mi ted by test the fac i l i ty ' s water storage system , whi ch coul d rocket not support operations l o nger than about 10 m i n a t ful l N RX -A5 i s operated successfu l l y at power for mi n The core conta i ned the far reactor as of that date J u ne spec i f i c i mpul se o f 845 s the same type of fuel el ements a s Phoebus-lA n ucl ear rocket eng i ne , 1966 February to March 50 m i n , c ool ant exi t temperature corresponds to a vacuum Ma rc h (CVD) proces s The peak was 5200 MW/m The I t was resta rted and reactor power s i gni ficant mi es tone Thi s te st seri e s was a in the nuc l ear rocket Fig 31 Q x a: w I- cc ::!: I er: J er: fz u J w z 00 :::;: 80 60 00 40 50 20 8,000 40 c;; 600 00 20,000 350 � er: _ u f- 4,000 10,000 ::> :::;: 10 � � "' 20 -' � 2,000 ::> 8000 :::;: 6000 4000 2000 • 0 0 10 20 30 40 50 TIME, F i g 38 ls) 60 70 80 90 100 0 Typ i cal ch aracteri sti c s of the nucl ear rocket eng i ne startup Note that chi l l -down of the vari o u s engi ne components takes about 60 s Then the eng i ne can b e turned o n to ful l power a t a rate l i mi ted by thermal s tresses i n the core resu l ti ng from the temperature tra n­ s i ent ( not to exceed about 83 k/s ) 49 e H Y D R O G E N P R OP E L LA N T TANK TAN K P R ESSU R E VALVE e F U L L F L OW T O P P I N G C Y C L E VALVE e S I N G L E -S T A G E C E N T R I F U G A L P U M P A N D S I N G L E -S TA G E TURBINE e R E G E N E R AT I V E L Y C OO L E D M E TA L -C O R E S U PPO R T E L E M E NTS I T I E T U B E S ) e RA D I A T I ON SH I E L D O F BOR A T E D Z I RCON I U M H Y D R I D E e C O N T R O L-D R U M A C T U A T O R S VALVE TIE TUBES e V A L V E S A N D V A L V E A C T U ATO R S e R E G E N E R AT I V E L Y COO L E D N O Z Z L E , A R E A R A T I O = CORE e U N C OO L E O N O Z Z L E S K I R T , E X I T A R E A R A T I O = R E F L E CT O R 25:1 00 : e U N C OO L E D N O Z Z L E S K I R T H I N G E D A N O R OT A T A B L E NOZZLE m 1 23 i n ) 4.4 m 1 74 i n ) e O V E R A L L E N G I N E L E NGTH = e T O T A L MASS = Fi g 39 W I TH S K I R T F O L D E D W I T H S K I R T I N PLACE 2550 kg 15620 lb) Schemati c fl ow descri pti o n of the Smal l E ng i ne conceptual des i g n The e n g i n e , which re qui red only f i ve control val ve s , was desi gned to produce kN of thru st from a 70-MW reactor e PRODUCES 365 MW e564 HEXAGONALLY SHAPED IUC-ZrCI C COMPOSITE F U E L ELEMENTS e 241 SUPPORT E L EMENTS CONTAINING ZrH NE UTRON MODERATOR e COOLANT CHANNELS PER E LEMENT ecORE PE R IPHE R Y CONTAINS AN OUTE R INSULATION LAYER, A COOLED I N BOARD SLAT SECTION, A METAL WRAPPER, A COOLED OUTBOARD SLAT SECTION, AND AN EXPANSION GAP e RE F LECTOR IS BERYLLIUM BARREL WITH 12 REACTI· VITY CONTROL DRUMS e CORE SUPPORT ON COLD END BY AN ALUMINUM-ALLOY PLATE SUPPORT PLATE RESTS ON R E F LECTOR SYSTEM e REACTOR ENCLOSED I N ALUMINUM PRESSURE VESSEL e CAPABLE OF F i g 40 50 83 K/s TEMPERATU R E TRANSIENTS Cro s s - s ectional descri pti on of the Smal l E ng i ne concept The overal l reactor d i ameter was 950 mm The des i g n u sed ZrH -moderated support e l ements , as was done i n Pewee , to reduce the uran i um cri tical ma s s FUEL FUEL E LEMENT e F UNCTION - P R O V I D ED E N E R G Y F O R H EATING H Y D R O G E N SUPPORT E LEMENT PROPELLANT - P R O V I D E D H EAT T R A N S F E R SUR FACE INNER T I E TUBE e DESC R I PT ION ZrH MODE RATOR u I N A COMPOSITE MATR I X O F UC-ZrC S O L I D SO LUTION AND C - CHAN N E LS COATED WITH ZrG TO PROTECT AGAINST I N SULATOR - 235 - OUTER T I E TUBE H R E ACT IONS T I E TUBES e FUNCTION - TRANSMIT C O R E A X I A L P R E SS U R E LOAD F ROM THE HOT E N D O F T H E FUEL E L EMENTS TO THE C O R E TI E TUBE SUPPORT COLLAR AND CAP SUPPORT PLATE - E N E R G Y SO U RCE FOR T U R BOPUMP - CONTAIN AND COOL ZrC MOD E R ATOR S LEE VES M I N I A R CH e DESC R IPTION - COUNTE R F LOW H EAT EXCHA N G E R O F I NCON E L - ZrH MODE RATOR 718 - ZrC INSU LATION S LE EVES Fig 41 Descri pti on of the Smal l E ng i ne fuel modul e de s i gn showi ng the ZrH s l eeve i n the regenerati vely cool ed ti e-tube support e l ement "SMA LL ENG I N E " STATE POI NTS AT DESIGN CONDITION PSOV 310 N/cm CHAMBER PRESSURE 8.51 kg/s CHAMBER F LOW RATE CHAMBER TEMPERATURE 2696 K REACTOR POWER 367 MW SPECI F I C IMPULSE 8580 m/s 7297 N THRUST 44.9% NOZZLE FLOW F R ACTION 1 8% TURBINE BYPASS F LOW FRACTION 4917 rad/s TURBOPUMP SPEED 0.93 MW TU RBOPUMP SHAFT WORK 65% PUMP EFFICIENCY 80% TURBINE E F F ICIENCY 2.63 cm2 NOZZLE VALVE AREA 3.02 cm2 TURBINE CONTR OL VALVE A R E A FLOW RATE PRESSURE TEMPERATURE STATE POINT DESCRIPTION (kg/sl (MPal (Kl PUMP I N LE T 8.51 0.12 PUMP EXIT 8.51 6.03 19.8 TIE TUBE MANIFOLD INLET 4.05 5.72 20.3 TIE TUBE FIRST PASS EXIT 4.05 5.38 56.9 428.9 R E F LECTOR 17.0 TIE TUBE EXIT 4.05 5.02 SLAT MANIFOLD I N L E T 0.64 5.72 20.3 S L A T F I RST PASS EXIT 0.64 5.24 167.1 SLAT EXIT 0.64 5.02 431.5 TURBINE I N LET 4.13 4.86 428.6 TURBINE EXIT MIXED 4.69 4.13 415.6 TURBINE BYPASS I N LET 0.55 4.86 428.6 NOZZLE I N LET 3.83 4.63 21.4 NOZZLE EXIT 3.83 4.21 240.4 R E F LECTOR EXIT 3.83 4.21 294.9 S H I E LD I N LE T 8.51 4.06 361.0 CORE I N LET 8.51 3.96 370.1 F U E L E LEMENT EXIT 8.33 3.10 2728.0 CORE BYPASS EXIT 0.18 3.10 370.1 CHAMBER 8.51 3.10 2695.A Fi g CONTROL DRUM ACTUATOR PRESSURE VESSEL COOLED NOZZLE UNCOOLED SKIRT ! LATCHED POSITION) De scri ption of Smal l E ng i ne operati ng parameters a t des i gn c ondi tions 51 STAGE M A S S , U S A B L E PROPELL A N T kg ( l b ) MASS, kg ( l b ) N U C L EAR STA G E ( I N C L U D I N G S M A L L E N G IN E ) P.ROPELL A N T M O DULE (1 8.3 m ) 7783 (39205) 2814 ( 28250) 23181 (51 05) 21 265 (46880) P R OPE L LA N T T A N K - 4.5 I -1� o.9 f���� 8.3 I - ·- - - �''i _ : :J,,J ALL D I M E N S I O NS IN M ET E RS De scr i pti on of a nucl ear rocket stage emp l oyi ng the Smal l E ng i ne and compati bl e wi th the space and mas s constra i nts of the space shuttl e Fi g • F U NC T I O N • D E S I G N C O N D I T IONS - P R ESSU R I Z E TH E P R OP E L LA N T F O R T H E E N G I N E F E E D SYSTEM XE' PUMP D I SCH A R G E 6.69 PR ESS U R E (MPa) (K) P U M P F L OW RATE (kg/s) TU R B I N E TEMP (rpm ) TU R B I N E F LOW RATE ( k g/s) SHA F T SP E E D 35 N E RV A 9.36 20.9 - 648 54 3.32 989 19 23920 SMA L L E N G I N E 6.03 8.5 429 4.1 46952 • CONSTR U C T I O N ( X E ) - S I N G L E-STAGE, R A D I A L- E X I T- F LOW-CE N TR I F U G A L PUMP W I T H A N A L U M I N UM I M P E L L E R , A POWER TRANSM ISSION THAT COUPLES T H E P U M P TO THE STA I N L ESS STE E L ROTO R S T U R B I N E , AND A TWO-STAGE T U R B I N E WITH • R E ACTOR TESTS E X P E R I E N C E - N R X/EST STARTS I N C L U D I N G 54.4 M I N U TES A T H I GH POW E R - X E - STARTS/RESTARTS I N C L U D I N G R U NS TO R A T E D POW E R • POTE N T I A L P R O B L E M S - S H A F T SYSTEM B I N DI N G AT BEAR I NG COOLANT LABY R I N T H I N X E T ESTS ( I N C R EASE C L E A R A N C E A N D I M P R OV E A L I G N M E N T ) - B EA R I N G L I F E F i g 44 52 Tu rbopump experi ence and des i gn cond i ti o n s for the n ucl ear rocket eng i ne propel l ant feed system . ACTUATOR MOUNTI NG FLANGE e F U NCTION CONTROL HYDROGEN F LOW IN T H E E N G I N E SYSTEM S P L I N E COUPLING R O L L E R BEAR I N G (2 PLACES) e CONSTRUCTION B I NARY VALVES EXCEPT F O R ANALOG CONTROL VALVES AND CHECK VALVES e R EACTOR TEST EXPER I E N CE N R X/EST AND XE-PR I M E E N G I N E SYSTEMS BUTTE R F LY SUPPORT SHAFT e POTENTIAL PROBLEMS :JllliiP - THRUST B E A R I N G SEAL DAMAGE BY CONTAM I NANTS E R RONEOUS POSITION I N DICATIONS LEAKAGE F ROM L I PSEAL TOLERANCES F i g 45 FOUR-INCH BUTTE RFLY VALVE (TPCV/TBV ) Ty pical cool ant val ve empl oyed i n the nucl ear rocket eng i n e STAGE PRESSURIZATION LINE TURBOPUMP NOZZLE TANK l> ROCKET MODE GAS D IRECFLOW TI ON ,l.f: I1 11r�OZZLE PLU( ROCKET MODE r l ALT �ODE GAS�\ \\ FLOW DIRECTION • + / d / / ,, - ·· �),;;1.��:, _ �· \ • F i g 54 Poppet val ve des i gn u sed to swi tch from a rocket propul s i o n mode to a power generati on mod e 57 Printed in the United States of America Available from National Technical Information Service US Department of Commerce 52S5 Port Royal Road Springfield, VA 2 Microfiche (AO I) NTIS NTIS Page Range Price Code Page Range NTIS NTIS Price Code Page Range Price Code Pase Rans• Price Code 00 -025 A02 15 1-175 A08 301 -325 A l4 45 -475 A20 026-050 A03 176-200 A09 326-350 Al5 476-500 A21 05 -075 A04 201-225 A JO 35 1-375 Al6 501 -525 A22 076- 100 A05 226-250 All 376-400 Al7 526-550 A23 J Ol - 125 A06 -275 Al2 401-425 AIS 5 -575 A24 126-150 A07 276-300 Al3 426-450 Al9 576-600 601- up• A99 •contact NTIS for a price quote A2S (/') { >·- r ' "' _ _; (_� (, ) f' UJ ... or reflect those of the United States Government or any agency thereof LA-10062-H History UC-33 Issued: May 1986 Experience Gained from the Space Nuclear Rocket Program (Rover) Daniel R Koenig... d fi rst regenerati vel y cool s the nozzl e and the The tes t­ nuc ear rocket reactors i s ; ng program for the summari zed i n Fi g o f the pro gram The These i ncl uded an a ssemb l y and... served a s an end i n the i n s i de wal l of the wh i ms refl ector for the outlet end of the core i nto the central The the central (Fig 15) and p a rt of the core , thereby by­ i nl et a