ML19220C687
| ML19220C687 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 04/04/1979 |
| From: | Bates A, Etherington H Advisory Committee on Reactor Safeguards |
| To: | Advisory Committee on Reactor Safeguards |
| References | |
| ACRS-MS-0011, ACRS-MS-11, NUDOCS 7905140031 | |
| Download: ML19220C687 (5) | |
Text
{{#Wiki_filter:' ( April 4,1979 H. Etherington A. Bates O c (25 m % i Three l'ile Island Accident gg The following ball-park numbers may be useful to Subcommittee members as background: 1. Poler level - 98% of 2772 fG(t) 3 2. Reactor coolant vuluma - 11,500 ft Reactor vessel volura - 4058 ft 3. Total heat generated fran start of com,ercial operation (12/30/78) ~7TOGUFJ' l'.. (I.~)- day 5~-{b25ed upon actual dar.uary 79 experience ano = maximum power in February and March) 4. Fuel Exposure - 90 days or less at full power 5. Decay Heat rate (fraction of average operating power, 2703 iid(t)), Tiine after shutdown 1 hr 1 day 1 week 30 days 30 days exposure 0.0141 0.0050 0.0019 0.00061 90 days exposure 0.0151 0.0059 0.0027 0.0011 1 year exposure 0.0157 0.0066 0.0033 0.0016 6. Total Stable and Long-lived N'oble gas generation fission yield, %: -5 l 31 Kr82 _ y 33).= 10 Xe - 2.9 Kr Xel32, 4,4 83 - .48 84 133 Kr
- 1. l '
Xe - 6.5* 85 l34 Kr 0.3 Xe - 7.6 86 l35 Kr 2.1 Xe - small-decays rapidly Xe * - 6.3 Total Kr = 4.0 Total Xe (max) = 27.7
- - decays rapildy in core = 5.2 d half-life Xe total probably
~ closer to 22.0 7905140031 Approximately s I 4.0 + 22.0 = 26% noble gases 235 1 gram U burnup = 0.95 tid-day power generation
Thrtr.flile Island i.tcide.nt 3r> 101,000 I"!3 x _l,_g, = 10;,000 cu U
- 0. 9 5 l'J.'O 101 r.g U 21.3 c;,/gn - aton 825 g,i - attus of Fission:6 U
= l'oble ger [a. ':c ticrr :.2G X 825 c., - e toms = 21,1 5 n - a to:.., 3 = 22.4 r,. 214 oles X 0.035 '/ 32 f t \\;aie t. 3 f.'oble 9es pret'uccd - 1CA ft at STP condi tioiis 3 l'axim i ne'le gr prc 'uced in core ICS Ft ct STP cond: t ici.: if cli i elc+ sed it ;oJ1d be small fracLior of 1000 fte L ubble in vessel ct 1000 PSIA. 7. Ge Fractior e r *'.il e - Te:.:Perature of watcr F 220 2f.0 2C0 223 300 S:.tura t ion p: enure, PSIf, 17.2 25. 35.4 49.2 G7 Sys tet.: pressure, P = 1000 lb gas pat tial pressurc, Pg - l'- PSat H O 2 gas fraction = 1 - 59t P for buit; cold lag fluid 200"i (i.ssuma vessel hcad tempercture and hot Itg aie similar) "4 gas frac tion = 1 An)g[]' gas fraction = 0.951 O 99 322
Three l'.ile Island Accident 8. Fer:g volur.c of non-condensable gas in 1000 ft3 bubble at 1000 PSIA 2c0 F. 5 Vol (1 atom, 70 F) = 1000 ft X47 X -f3 Vol (1 a top,, 70 F) = 46,4_00 f t3 if all noble gcses are contained in the bubble then 46,232 ft3 are hydrogen and other trace gase! 9. Following bubble removal, containment measured at 2.3% H2 (11:00 p.m. April 1) Containment volum? = 1.98 X106 3 ft at 2.37 = 45,500 ft3 g 2 numbers in (8) and (9) agree within 5% (surprisingiy) 3
- 10. Assur 46,200 ft g7 g from metal water reaction -
2 Zr + 2 H O M Zr02+2H2 2 moles of H in bubbit 2 3 .0 532 ft 2
- r. x h-
= 46,200 ft y 3 X = 51,200 gm-moles H2 = 112 lb-moles H2 91.22 lb Zr/ mole X li2 moles = 5120 lb 51 20 lb Zr reac'en. Fuel - 0.43" OD thickness 0.0265" Zr per ft of fuel = n X.417" X.0265" X I 2 I4 in 2 = 2.42 x 10-4 ft /ft / = 6.5 X 62.43 3 = 406 ' b/ f t 3,3 Z'r (lb/f t) = 406 X 2.42 X 10-4 =.0080 lb/f t
Thiec 11ile Island Accident 5120 lb reacted - 52,300 ft reacted ^ .0900 lb/ft fuel in core 177 assemblics 208 rods /asse:r.bly 12 ft rods 442,000 f t of fuel = approximately z,f2'[00--~ or 19% of clad reacted One would assume thtt only the hotest portion of the clad would react, thus damaged feel would be considerably above the 12% of the clad that reacted.
- 11. Removal of H from the gas bubble in the vessel.
2 H solubility in H 0 2 2 at 1 atmosphere U 2.1 cc/iOO gm H O - OC 2 .85 cc/100 g,n H O - 85 C 2 also XA = Pg/H where X is mole fraction of H in liquid phase A 2 P is partial pre,sure of H in gas phase in atmospheres A 2 H is Henry's has contact 0 H at' 23 C and 8200 ctn pressure (lig) 4 11 = 8.4 X 10 function slowly increases with temperature and pressure - 4 assume H 8.8 X 10 g iom (7) is 951 PSIA /14.7 = 65 atmospheres f P 9 9 3 2 'l-
Three Miles Island Accident.XA* XA" 8 XTO
- X4 = 7.4 X 10-4 moles H /IS N 0 2
2 -4 lb H /lb H 0 = 7.4 X 10 X 2 lb H 2 2 2 mole 18 lb H 0/ mole 2 lb H /lb H O =.82 X 10-4 2 2 under reactor conditions at 1000 PSIA 3 112 lb moles H in 1000 ft bubble - (section 10) l 2 i 112 X 2 = 224 lbs H l 2 lb H O required to disolve H 2 2 , 224 lb !!2 l ~ 82 X 10 4 lb H /lb H 0 2 2 6 = 2.73 X 10 lb H 0 2 Hydrogen was stripped out of water in pressurizer. If ont assumes complete s tripping from the water and continued solubility of H in 2 H O at the initial level encountered in the pressure vessel one 2 6 would have to pump 2.73 X 10 lb H O through the pressurizer sprays. 2 In actual practice the quantity would be larger due to non-equilibrum effects and the Lima required for the H to diffuse 2 vessel water. Prestorizer licater - 1650 KW vressurizer spray pumps normal continous = 1 gpm 9c N '. J maximum = 350 gpm - maiimum continouc spray rate based or heater
- ^
capacity,and 2800F spray water - 58 rpm 3 ~ at 1000 PSIA 110 = 46 lb/f t 2 3 7.481 gal /ft
Three Mile Island Accident 6 3 2.73.X 10 1 b X 1 ft X 7.481 nal X 1 min 3 46 lb ft 58 gal = 7.73 nin/60 min /hr "~ 129 hoorsE e It would require on the order of 5-6 days to achieve removal of the quantities of flydrogcn suspected of being in the reactor vessel head. If the initial conditiens started with primary coolant s.aturated with H the initial removal from the bubble would be small'and slow until p trie concentration of the H in the water was lo ered enough to bring 7 more of the bubble into solution as a concentration gradient for diffusion was established at the water surface. 12. Fuel pressurized with Helium at 2000 PSIA. fuel rod I n. = 0.377" fuel pellec 0.D.= 0.365" fuel height = 144" rod length
153.125" volume available for Helium in rods around fuel pellets
= x X 0.012" X 0.371" X 144" 3 1728 cu in/ft
1.16 X 10-3 ft3 Helium at ends of fuel rods
= w Y (.182)2 X 9._125" D28 =.55 X 10-3 Helita volume / rod = 1.71 X 10-3 ft3 Number of rods = 208 X 177 = 36,816 3 itelium volume available_,in rods = 63 ft rods pressurized at 3000 PSIA if all helium ' leased to vessel then approximately 125 ft IIelium was available ut 1000 PSIA in the reactor vesse.1 bubble. Henry's law contact, H, is larger by 50% for Helium; however the smaller amount of IIelium available would allow all of the gas to be dissolved in the primary system and removed faster than the itydrogen in the bubble. 99 326}}