22.033 Cor e Gr oup - R eact or Cor e an d Seco ndary Design

R obert Dr enkhahn Br endan Ensor Jessic a Hammond Ruaridh Macdonal d

1

Ov er vie w

• Pr oposed Des ign & Specs

• Cor e

• Sec ondar y

• Ne x t St ep s

2

Pr eliminar y Design

• Lead Cooled F as t R eact or wit h Super crit ic al CO 2 Sec ondar y Loop

• 1000 MWt (~450 M W e )

– Limi t ed b y v elocity of LBE (2.5 - 3 m/ s) curr en tly w e ar e u sin g 2.5 m/ s

– Subject t o c hang es as Δ T and flo w ar ea chang es (w orki ng on up pi ng it t o ~1200 M Wt )

3

Pr eliminar y Design

• Blac k - Fuel R eg i ons ( UO 2 )

• P urple- Con tr ol R ods (B 4 C)

• Be i g e - R e flect or (MgO )

• R ed - Shield (B 4 C)

• Or ange - Cool an t (LBE)

• Not e the B l ue c on t ainment i s not the a c tual c on t ainment (i n r ea l i ty i t i s l ar g er)

4

5

Cor e Design Pr ocess

• Us ed M CN P (Mon t e Carlo N - P arti cle) c ode t o desi gn r eact or

• Based of f of o ther si mil ar he x ag on c or e shaped li quid me t al c ooled r eact or s (S T AR - LM, ELS Y)

• Des ign It er a ti ons

6

It er a tio n 1

• V er sion 1 .0, loo k ed a t a lo t of r e f er ence design s a nd cr ea t ed some thing similar

• Se e if it w er e cr iti c al

• Fue l Pin de sign: fu el  LBE g ap  pr ot ect iv e clad  T9 1

 pr ot ect iv e clad  c oo lan t

• It had the whol e r ang e o f S/D wit h r ods in and su per crit ic al wit h r ods out

– Need ed less r eacti vity a t t o p o f c o r e ( help s with S/ D mar gin)

– Ne ede d less po w er peaking in th e mid dle

7

It er a tio n 1

8

It er a tio n 2

• Ad ded Axi al Z onin g t o fix the lar g e e x cess r eactivit y (20 % enriched Low e r , 15% enrich ed Mid dle, 10% enrich ed bot t om)

• Add ed Radial Z oning t o g e t a fla t t er flux pr ofil e (Added 5% t o the out er ri ngs)

9

It er a tio n 2

• Blac k - Fuel R eg i ons ( UO 2 )

• P urple- Con tr ol R ods (B 4 C)

• Be i g e - R e flect or (MgO )

• R ed - Shield (B 4 C)

• Or ange - Cool an t (LBE)

• Blue - Cladding (T 91 s t ainl es s s t ee l , pr ot ecti v e out er l a y er)

• Not e the B l ue c on t ainment i s not the a c tual c on t ainment (i n r ea l i ty i t i s l ar g er)

10

It er a tio n 2

11

It er a tio n 2

12

P o w er Calcula tion

• Use d P o w er = ṁ c p Δ T

• Wh er e ṁ = ρ v A

• Wh er e v is li mit ed a t 2.5 m/ s, rho is 10500 k g /m 3

, A i s the cr oss se ctional c oolan t fl o w a r ea, c p is 150 J/ kg·K and Δ T i s t he t emp er a tur e chang e acr oss the c or e

• Dir ectl y pr oportion al t o A and Δ T

13

Dec a y Hea t R emov al

• Aft er a mon th of shut do wn fr om long oper a tion s til l pr oducin g about 3 MWt of ener gy

• Aft er a mon th of shut do wn fr om 1 mon th of oper a tion s til l pr oducin g 400 kWt of ener gy

• Ne ed t o see ho w m uch p o w er pr oduced i s suf fi cie n t t o k ee p LBE liq ui d and then w ork with pr ocess h ea t

14

Sec ondary S y s t em

• Model ed i n EE S

– T emper a tur e and mass flo w c alcula tion s

• Ini ti al As sum p ti ons Made

– Hea t e x chang er i npu t and outpu t f or S - C O 2

– Low end t emper a tur e aft er c onden ser

• Al lo w s f or f as t er op ti mi z a ti on in th e futu r e

15

Sec ondary S y s t em

16

Sec ondary S y s t em

• Mor e S - CO 2 da t a r equir ed t o perf orm analy sis of pr essur e chang es.

– En thalp y T able s

• P ossi ble sec ond loo p with an added r e - hea t er and c ompr essor t o a cc oun t f or chang es in specifi c hea t

• Ener gy div ert ed t o Pr ocess - Hea t needs t o be acc oun t ed f or

– On ly majorly e f f ec ts electric ity g ener a t ed

17

Br a y t on Cy cle: Quick Ov er vie w

Source: UC Davis ChemWiki, license CC BY-NC-SA 3.0

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LBE & S- C O 2 Hea t Ex chang er

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h tt p ://w w w .h e atr i c .c o m/

• Pr in t ed Ci r cuit Hea t Ex chang er (PCHE) v s. Shel l -

and - T ub e Hea t Ex chang er

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PCHE

• Compac t design

• Competitiv e E f ficie ncy

• Fric tion F ac t or f or LBE bec omes ob s t ac le

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She ll - and - T ube Hea t E x chang er

• Simpl e design (ea s y t o mak e, lo w c os t, e t c. )

• La r g er than PCHE

• Competi tiv e e f ficiency

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http://www.thermopedia.com/content/1211/?tid=104&sn=1410

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Ne xt St ep

• Sec ondary: Be t t er da t a, mor e accur a t e v alues , possi ble sec ond r e - hea t er/ c om pr essor loop, and pr ocess hea t r emo v al

• Cor e: Na tur al Cir cula ti on, Dec a y hea t w ork, c on ti nue op ti mi zi ng c or e z onin g , the rmal analy si s of f uel

22

QUE S TIONS?

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MIT OpenCourseWare http://ocw.mit.edu

22.033 / 22.33 Nuclear Systems Design Project

Fa ll 2011

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