Document gaGEO1x404eM8ZRrEQ52vzE5J

0 Date: July 8. 1975 1500- 2300 "D" By: R. Collins At 2200 hours, D-300 Reactor blew a Safety disc, 4" disc under relief valve, east of man-way . Product - 5303f, set point - 150 Charged at 1810 hours. Safety disc blew at 154 psi and 156F. Panel operator (Bobby Chaffin) had just put emergency cooling on re actor to control, but this did not help, he then sent field operator (Mike Gray) out to try to control runaway by addition of 1 gallon A.M.S. to re actor. Disc blew as A.M.S. was being injected to reactor. (Mike Gray), field operator then rushed back to control room. At this time D-600 reactor was being recovered, panel operator (Bobby Chaffin) shut D600 recovery off and started recovery on D-300. The vapor release no. (62) was then dialed and location and cause given. Dryers were then shut down, call was made to dryer lead operator by re actor panel operator to make sure dryers were down. Guard on duty was called and was told to stop all traffic at gate. Approximately 3 minutes after disc blew, relief valve reseated. After waiting 5 minutes, field operator (Jerry Minor) put on Scott Air pack and checked out area with century unit still had some high V.C. readings of 35-50 P.P.M. Waited 10 minutes and field operator (Mike Gray) put on Scott air pack and checked area with century unit. Area checked out 10 p.p.m. or less. Honeywell chromatograph showing less than 25 p.p.m. all stations. Then the all clear no. (63) was dailed guard was called and also dryer department lead operator notified. Normal operations then resumed. No Honeywell readings above 1.0 p.p.m, were encountered in the dryer room during this period. The highest Honeywell readings in'rthe large reactor area sample points during this period^are listed below: 1. Control room - 3 ppm 2. 401 VCM Receiver -6 ppm 3. 1st floor at H-- 5 -50+ ppm 4. 2nd, floor rec system -24 ppm 5. outside, by sweco - 12 ppm 6. 1st. floor, D/300, 4.00-39 ppm Vo 7. Top of D/300 - 50+ppm '* 8. 1st. floor at D/500 - 8 ppm 9. Top of D/600 - 9 ppm 10. Air line - No No personnel were exposed to VCM levels higher than 25 ppm during this VCM escape. One man, Jerry Minor, was exposed to 35-50 ppm VAB.0001042843 s Page 2 while he was using a Scott Air Pak. (~f\fr-> / Rodger Collins CC: RPG, Jkvr, rwn, uro, mo, iwauiu 54^iuJ.*oxS, Dryer SUpeTVisors k VAB.0001042844