ML20002E098

From kanterella
Jump to navigation Jump to search
Discusses Performance Characteristics of 21 Modified Type F Fuel Assemblies W/Hollow Ctr Rods,Substituted for Fueled Spacer Capture Rod at Facility.No Significant Hazards Considerations Presented.Further AEC Action Not Required
ML20002E098
Person / Time
Site: Big Rock Point File:Consumers Energy icon.png
Issue date: 03/08/1973
From: James Shea
US ATOMIC ENERGY COMMISSION (AEC)
To:
US ATOMIC ENERGY COMMISSION (AEC)
References
NUDOCS 8101260373
Download: ML20002E098 (6)
v • d • e


Text

{{#Wiki_filter:., - 6 t Mt te, [gd UNITED STATES , !,\\g ATOMIC ENERGY COMMISSION ' ~j ), W ASHINGTON. O C. 2054S e %n e' pY b MAR c M3 ' files (Docket No. 50-155) iHRU: R. L. temann, Chief, ORB #2, L GK. e BIG ROCK POINT 21 MODIFIED TYPE "F" FUEL ASSEMBLIES WITH HOLLOW CENTER RODS (CONSUMERS POWER COMPANY)- By letter dated December 18, 1972, Consumers Power Company (CPCo) described the changes in performance characteristics of Type "F" fuel assemblies due to substituting a hollow (unpowered) rod at the bundle center in place of the fueled spacer capture rod. The last 21 fuel assemblies of a complete 84-bundle core fabrication order have been modiffed using a hollow center rod in place of a fuel rod to provide a heat sink at the center during the period following the postulated loss-of-coolant ageident (LOCA) in the. manner described for the Reload G fuel assembliestl). Type "F" fuel was inserted during the 1971 and 1972 Big Rock Point core refueling. The remainder of the original 63 bundles delivered prior to May 1972 will be inserted along with the 21 modified Type "F" fuel assemblies during the 1973 refueling beginning in March 1973. The modified Type "F" fuel assemblies are mechanically identical to the original bundles differing only in the substitution of the hollow center rod. Our review of the analysis results presented by CPCo disclosed the following: 1. Following the DBA (double-ended break of recirculation line), the hollow rod temperature peaks in 190 seconds at 2700'F, at the same time the cladding on the adjacent fuel rods peaks at 2730*F. 2. Following the DBA, the original Type "F" center fuel rod cladding peaks in 330 seconds at 2740*F, at the same time the diagonally adjacent fuel rod cladding peaks at 2700*F, according to the enclosed Figure 4 submitted by CPCo with the NFS fuel performance analysis on May 18, 1972. 3. The power produced by the 8 center rods of the modified Type "F" fuel is the same as the power produced by the 9 center rods in the eriginal Type "F" fuel assembly, i.e., the power in each of the 8 rods surrounding the hollow rod is up by 12.5%. ?t tM/3'B

'~. Tiles MAR 8 1973 4. Local power peaking is reduced from the 1.24 value for the original Type "F" fuel assembly to 1.22 for the modified Type "F" design. Because of the significant difference in the heatup rates for the modified Type "F" fuel cladding as reported by CPCo in contrast with the rates shown in the enclosed Figure 4, cubmitted by CPCo in May 1972, we requested, during telecons with CPCo personnel on December 21, 1972; January _ 30, 1973; and January 31, 1973, cdditional supporting information. Specifically it was requested that peak clad temperatures as a function of time af ter the DBA be provided for the hollow center rod of the modified Type "F" bundle along with the peak fuel rod clad temperature and the position, relative to the center rod, of the hottest. fuel rod clad. Since the local peaking factor decrease is relatively small, 1.24 for Type "F" to 1.22 for modified Type "F", with the claim that the center rod power increases by 12.5%, it also was requested that the fuel rod power distribution for the original and modified Type "F" fuel be provided. A' faster rise in peak fuel rod clad tenpara-ture in the modified Type "F" is consistent with the increase in the power produced by the rods surrounding the center rod, but the relative behavior of other roda within the bundle nor the claims of improved critical heat flux ratio at rated power conditions in the outside high power rods cannot be evaluated without the requested information. By telecon on February 5,1973, CPCo provided the additional data points for curves 1 and 2 plotted on the enclosed Figure 4 and bundle power profiles as shown in the enclosed Table. We have concluded, based on information provided by CPCo, that the replacement of the center fuel rod in the Type "F" fuel assembly by a hollow center rod is of marginal value with respect to improved core safety following the DBA since the peak clad temperature remains nearly unchanged (2740*F reduced to 2730*F) and the time to reach peak temperature is reoaced by about 2 minutes (320 seconds reduced to 190 seconds). The additional data provided in the enclosed table, while not directly comparabic, is indicative of the increased power generation in the rods adjacent to the ~ hollow center rod and the reduced power generation it the outer 1 row of rods; hence, improved, i.e., higher, critical heat flux ratios as claimed. For the more probable smaller break sizes, however, the modified Type "F" fuel assembly does resylt in reduced peak clad temperatures assuming automatic depressurizationt2); and in this respect, the modification (subject to confirmatory unpowered rod wetting characteristics data from GE tests which is expected to be available in March 1973) is clearly beneficial. Peak clad temperatures remain below 2300*F for breaks' as large as 0.12 f t compared with 0.04 ft2 for the original 2 Type "F". It should be noted, however, that at the present time the Big Rock Point plant does not have the automatic depressurization capability assumed in the small break analysis. w ~,, ,--n

+. MAR 81973 Files. - [We have' conclude'd that the change as' described by CPCo does not -present significant hazards considerations not described _or implicit in the Big Rock Point ' Safety LAnalysis Report. and that there is reasonable assurance that the health and safety of the public will not be endangered by . operation of the reactor-in the manner proposed. No further AEC action on this matter is required. s 4% James'J. Operating Reactors Branch #2 Dircetorate of Licensing

Enclosures:

1. References 2. Figure 4

3. ' Table cc w/ enclosures:

AEC PDR RTedesco, L:CS (2) DJSkovholt, L:0R TJCarter, L:0R R0 (3) DLZiemann, L:0RB #2 JJShea, L:0RB #2 P.MDiggs, L:0RB #2 i 1 5 4 ) s 3 i

. = _, 4 ~.. l REFERENCES 1. Change No. 34-to Facility License No. DPR-6 and memo to file,. " Reload G and NFS-DA 11 x 11 Rod Bundles with Unpowered Rods and Plutonium", dated December 6, 1972. J 2. -DL letter to CPCo dated January 5,1973 regarding~ automatic depressurization -.one of four requests for additional infor-mation. 2 i h-1 d F l i a T 1 4 4 { t 4 a M - A J i e w +rw-e-.e-d= --s* 1'4r' = e w-r s en-+ e e--- --e- -<pt~i y -e-we' w cm T' r$

a..------..-..-.w -- %3 -. -..- l .'.....i.i.... ... e i s t.... ..},.... O 8.......I..... ) *L. l.t)_....o.. Q. '3. 86 .s R gi. .....8 ......I.....

o. a.

aI 3 I l o i O . e n'. d ;

a. I n.

x : nr * "l- .... " '. _\\. "~ ~. )c. p -- t o" o:

  • q ;

. D,. .y... e w & m I w.. ' o-T'-{ (N g l I l i l..... *

4..

O_ /8 .......l

  • U

'l .C... /' 3.. _Ul..g'. O .l cd / ! /. g .) c%, c', i :z o I e i i, ..l... .. /lA. ...l.. O. ... ~ e;g _ / .l. .p,. s y / e l-:... s Q 1 ... N I. . d l 1 a. ...( .O _'.iI C e.%. '. _.... .-.._l ..j - -.-...*.._ d ~l.n. .~(d.- 8. '-._. C N s..z. .i ~ tN, .i t .....%,. O. ~. _..... _.. _. _._.a........ _.- _. _.. ...y \\ g .j j.,.. i- -

....\\.. j

..-.........,..v.j-. %...,, n - o -.. ~,... .y s o .,....y -.. +... ..,a.- m i t; .o ,.. { ; i... s ., g

M l s J,i-;l O O.O. @ r.@.-

'-,7 - p "; T .i i s @ O O.@l g' t:n .--- r;;- -$ ; pr-c-g . J. g. W,i.. a h-o i "dt I" 1 r j,4, : o 'i f 9.v t

0. 0A@..1. i i..il.

4. ' '-.Q-..... i s o.

a

.: n. *..,. I ~ " . m. l.....tS. Z. \\ ~.. --O - - -. - - l-- i i.t... i.- - { ......:(.."... ..t,j i .7 -g g g., ..g-g . - ;- - L1.*, -N,. y,-- -f ;.- - - - g-- 1;.P- -, - -

  • k...... I. _'.._ 1 -

... _..j _.. . _ ;-, p\\....r_ ~.. h;... _. .l%.. * .. I'...3 l. \\g._.. __......__I.. 1.l.. W i . g:.,,.. ... j. g i.. '. '.. '

  • l i ;.--

?.. f. (D. 1

n..g !..!_ O b.......t

.] ~. c 3 ..... 13.... W Z o. g. N. j. l..,.. ...., t..... : i,....g.34 ! *. l t, .. [1]. a. .g d i ... _ _ %w. .I ..'.. O..... _. a ..t g.i.. _., , I _. . h_. ..! : (,. : <'.:. ,\\.a_.' .e _..s..... q. -. s... ll!..... ... ',.n.. y.. .-3 \\ y.:. g '.. j _. p....,. 3 el. i . f-3. :...... _ ;_...... . _.. d.).... ~ ' .-... l\\ .i. O l .'.. '..- c. i i. ... o.. n.... i. .,...m._ ' g. 1-t7 i .. \\..,........,..,....; i..... . i. ..Q... s <. .s ... d",

1...,- -,.. g. IL. 7l ffD

., 11.,. T.... 4 s.g.. D.. ,.e . !.a...,..l....., . La....,. r... % L s.As. . c.h.,, + o_. _F... .f......... .,...c.

l....

.s .g, a;_g ... q... i t, u.

g.. g _.

aj \\_ b g ,+,Y .C ,14yl.y,e.Q,.y. u.. h,.-.TI,d .. LLI gr, ....u. 1.. '; t ty - D.,, D,.. .,A r. g c. ~. Id.._ _.... .\\ ._...."1.'. .. II oc: m,..

4. _.

.o c..!. 0 .....:j:.>l..\\

k..... a-4 7. vt.-H.. u

...i E_ 3 H.. .... P, - H' o ;.. ~... ,9,_j o. \\. - 1. 4.... 4 ; 3 1...I_?... .Q. %. ' J-F - ; F. . h... .I

  • j.

.g,.

- tW

.1 . O'.. '. 6 ... d..., N.. g....:... _ \\.,. I....... g /.L.;_. 1-~. se s. __]. t j, .. ;t y 3 .._ _4 c ^ ......t..'.'..-.......!...._,;_...i.e :.. f.. i -....... s s i 5

  • ._...T_.s

.D.;..... I 8 e. i' j 'I .. \\. _.- ....a_%..). .. F. g;. .,. _.. a_......;...... r.: . ;....] __.. g: q.z.K..q.

; g !

. p,......, _.. _.ul _t . l h I ? 'l i .a. _. y..

  • 2 u

s l .*4.. JJ. J.. ,c, . '.... __. p.... . -.-. l. g.... I. _..L.._....,..., . f f-q,.,..... ' .. 6,.. 3.. l .4. a'f.. _Q_.. : 6 .._...._....._.-.l...J.g g . y _ :., .r.. _,.L e .0. \\..,.I... .a s 1 j. a,. \\ _ -. t.. .. h_,,.. O. 8 ae [ ... y{ - \\ i_........... l i ...,..O,., ......r.-:.....,. -.L c..... :. :.. j g l... ..,,I 8 \\

  • l, g

.__-7... g. i.._. n.__....__.._ i. .....l..... i i g ..i __..i,.. .i ..i. _.. 5.... J.!.. J... . j i e 6 t .i i .N.. .al _.. i 1 .. _t _.6_.-_ ..-l,... ,e.,, . i, ;.; 1 [. ..3., .t . t. .t .i_.. 8.,,. .l i, .i y.,. j.gg, /_ ..; o.....g. ..a J. ... 9 3i,c. 8: -o. o .O. .pu o' A .3.l.*} : o... ; :m.. i i,.. o.. ' ' f f.. f :. .I

4. 5

... D 2 4 ....O...g I t. i i ...,;.M i e 9;;..Q .!i LQ. s.; 4.y c.Ia 1. i. 5 k an

TABLE Power Distribution - Modified Type F 15,000 mwd /t Depletion 0 1.074 1.016 1.126 1.116 1.064 0.978 0.909 0.886 1.033 0.952 0.935 0.910 0.930 0 Power Distribution - Type F 10,000 mwd /t Depletion 0 1.153 1.020 1.167 1.149 1.087 0.983 0.905 0.880 1.017 0.930 0.909 0.855 0.835 0.811}}

Retrieved from "https://kanterella.com/w/index.php?title=ML20002E098&oldid=4683124"