ML20024F168
| ML20024F168 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 08/31/1983 |
| From: | Harold Denton Office of Nuclear Reactor Regulation |
| To: | Herman A AFFILIATION NOT ASSIGNED |
| References | |
| NUDOCS 8309080310 | |
| Download: ML20024F168 (7) | |
Text
{{#Wiki_filter:. o. AUG 311983 Ms. Alice A. Heman R. D. #5 York, PA 17402
Dear Ms. Herman:
Your August 12, 1983 letter to Commissioner Gilinsky has been referred to me for response. You ask if the change to the ventilation system in the TMI-2 reactor building would result in more radioactivity releases to the environme nt. The TMI-2 reactor building ventilation system consists of two paths with each path capable of 25,000 cubic feet per minute (cfm) of ventilation flow. Each path has installed in-line filters (2 in series) and the removal efficiency of the filters is greater than 99.97% for particulate radioactivity (e.g., particles of Cs-137). The filters are periodically tested to ensure their perfomance capability. Each path is capable of operating in the recirculation mode or in the purge mode. In the recirculation mode, the ventilation flow is filtered and directed back into the reactor building. In the purge mode, the venti-lation flow from the building is filtered, monitored and released to the environment via the plant stack. The monitoring ensures that any releases ci radioactivity to the environment are within NRC limits. In addition to the monitoring by GPU of releases from the plant stack, the EPA, NRC and GPU regularly perfom monitoring of the plant environ-ment to provide independent measurements of radioactivity levels at various locations around TMI. As you know, this information is published weekly in the NRC-TMI Program Office Weekly Status Report and typical readings indicate that radioactivity levels are at nomal background levels. Until recently, GPU had been operating just one ventilation path in the purge mode and the other path was on a standby status. However, GPU recently started the second train in the recirculation mode to minimize the concentration of particulate radioactivity in the reactor building air. This action draws slightly contaminated air from the building, collects the particulate radioactivity on the installed filters, and directs the clean air back into the building. This action may further reduce the already small releases to the environment and will certainly benefit the workers in the reactor building. This action will not result in more radioactivity releases to the environment. 030908031o 830031 o {D" 'G O poa Apoca osooo32o PDR H ...o a.n........... ao&..... -e nayya......e.o.aM).w...k.g.. .Sener.as...n.d.En.e.r..... ....so....g.......um.r.cu...... ...s.G..d... e....... n ,,,,8,/, 8 3,,, ,,,,8,[ ,,3,,,, ,,3jgg33,,,,,,,, .BM2/0.3,.,,,, , 8/J,,[,8,3,,,,,, omy OFFICIAL RECORD COPY usaeooni-mm unc ronu aia no-soi nneu ono
Ms. Alice A. Hennan I trust this answers your concern aE>out the change in operation of the reactor building ventilation system. Sincerely, Original Signed hg gJi,R.Danten s Harold R. Denton, Director Office of Nuclear Reactor Regulation
Enclosure:
Excerpt from Weekly Status Report for July 24-30, 1983 ^ M .2 %( gA t % ~ 7%jg3 orne., SUR8eAME) o4re > NRC FORM 318 04 NRCM ONO OFFICIAL RECORD COPY usom issi.-asseo
Distribution: Green Ticket #13453 Docket No. 50/320 NRC.PDR w/ incoming Local PDR w/ incoming E00 R/F TMI HQ R/F TMI Site R/F.w/ incoming - BJSnyder LBarrett RAWeller TPoindexter P91asnik PGrant LChandler, ELD OCA (3) PBrandenburg (#13453) DCS w/ incoming MGarver (#13453) WDircks - JRoe TRehm VStello Denton/ Case JFunches DEisenhut RVollmer RMattson TSpeis HThompson NGrace SECY 83-2181 i L l 1 0 i-l 1 u m.
E,< c W r* FM wcge. y r rn ru s A E F M 7~ FO< T v '- Y 2 Y -- j o, / M ENCLOSURE 'i ~ REACTOR BUILDING ACTIVITIES: ~ 1 Three reactor building entries were completed during the week of July 24, 1983. Reactor Coolant System depressurization and partial draindown to support the next phase of the reactor vessel Underhead Characterization Study is proceedin_g on schedule. The primary system was depressurized and the pressure boundary closure plates on top of the control rod drive mechanisms were removed. As anticipated, there has been no change in cverall reactor building radiological conditions during this evolution. It is anticipated that the primary system will remain depressurized and partially drained through head removal and detueling. ~ Four reactor building entries have been scheduled for next week (week of July 31, 1983). During these entries, preparations for control rod drive mechanism (CRDM) removal will be performed. CRDM removal is scheduled to ~ comence on August 10, 1983. The Underhead Characterization will be performed during the latter part of August and during the first two weeks in September. Other work is continuing inside the reactor building in paral' lei.with t'he Underhead Characterization. Housekeeping and localized decontanination tasks-are typically performed on every entry. During the past week a four inch diameter hole was drilled through the 3 f t. thick concrete floor on the 305 ft. elevation to gain access to the reactor coolant drain tank (RCDT)~. Procedures are being written to drill through the 14 in diameter rupture disk pipe, which protrudes from the top of the RCDT, to sample the drain tank contents. The 5 RCDT has not been sampled since the 1979 accident. s REACTOR BUILDING DOSE REDUCTION ACTIVITIES: Cleanup efforts in the TMI-2 reactor building began in the second half of 1980, follNing the purge of the krypten-85 inventory. Since then, there have been 264 entries into the reactor building. Cleanup efforts have primarily been I directed at radiation mapping, data acquisition, rurface decontamination, dose l reduction, sump water processing, polar crane. refurbishment, and core damage l assessment.- The total dose incurred to date in the reactor building is approximately 633 person-rem. However, the licensee is establishing more l large-scale labor-intensive cleanup efforts in the building, including ongoing decontamination activities, polar crane load testing, pressure vessel head removal, plenum removal, and fuel and debris removal. Efforts to decontaminate the reactor building to date has reduced the general area
- radiation levels on the 305 ft. and 347 f t. working elevations, however the ugnitude of the reduction has not been as great as initially hoped for.
A special dose reduction effort was initiated in late 1982 to shield and remove j incwn sources of radiation, and to inprove ingress and egress pathways in the reactor building and to shorten transit times to work' areas.,Although this i effort has had a measure of success in reducing the radiation levels and personnel exposures, further reductions in general area radiation levels are l likely to be ditficult to achieve. Identified sources of: radiation and radioactive material (contamination) such as Cs-137 contaminated concrete surfaces, block walls, and cable trays, have proven very difficult to d: contaminate. General area dose rates at the 305 ft. and 347 ft. elevations '~ W * -'e--- =
.s >E Al, ~ 2 w. are no,e abost 140 mrem /hr and 110 mrem /hr as measured by work m 'dcsimeters. The mean loose contamination is about 4.3 x 10 5 dpm/100 cm2 305' elevation and about 7.5 4 10 dpm/100 cm2 s on the loc &lized shielding, decontamination andThe licensee is continu trans. coolant system and reactor building sump. processing of water from the reactor l Because of the cleanup delays caused by financial problems and th encountered in reducing dose rates and contamination levels in the re iculties ! building, the NRC staff has considered supplementing the Program ~ j Environmental Impact Statement (PEIS) on TMI-2 cleanup. e 1961 (NUREG-0683), estimated the cleanup would be completed occupational radi 8,000 person-rem.ation dose for the cleanup to be in the range of 2,000 to e Based on the delays to date and personnel dose experie .from the 264 reactor building entries it appears that the clean in an occupational radiation dose in excess of the 8,000 person estimate. update the estimate of possible occupational rad environmental impacts. The supplement to the PEIS will be prepared n a this task. National Environmental Policy Act and 10 CFR Part 51 opportunity to provide comments on the draft supplement when it is p later this year. y The TMIPO staff continues to closely monitor GPUN's efforts to red k tional radiaticn exposures. GPUN has a special program to implement actions to cupa- . minimize Reactor Building occupational exposures as part o to maintain all radiation exposures to as low as is reasonably a hi (ALARA) levels ~. _ July-28,1983,.at the site, on the status of its programs.G c evable other dose reduction activities were described by GPUN.Decontamination and I discussed in the context of the potential for affect IMIPO staff's preparation of the FEIS supplement. and the g ( included defueling, chances to reactor building ventilation tj reduce a Other items discussed 1 contamination and surface recontamination ~, tfie evaluation of cable ( r orne j sources of radiHioGmping of the eTevator pit and the need for careful k planning of activities in the reactor building so as to meet progra L while maintaining personnel doses ALARA. ves SPENT FUEL POOL "A" REFURBISHMENT: i description in previous Weekly Status Reports) h ee ible pump that allows complete transfer of weste from the lower t a submers- /" vrper tank' farm. anks to the ~he SDS spp dischErge pipe has been rerouted t 1 M cds. that a direct connection bypassing the tank farm now exists bet ~ '- , so building sump snd the SDS. ween the reactor ~ 4 W I
f jmee/.wers.[ } ') ) ACTION CONTROt DATES CONTROL NO. _ Fh 9-r-83 13453 A DATE O DOCUUEkT m, ica,u atav /' ) ~ 8-12-83 I( ()j, ~ i e PREPARE FOR SIGNATURE 70' \\, / u OF: 5 p/67/b $",^"Yh{W v nNAt acety /[! [~ /,g Corsa. Gilinsky / nte LOCAnOr s / orwen otsCRipnON Ot E n O ucuo O nepont O orst( SPECiAdiTPUCTIONS OR REMARKS Concerns re venting-at THI 2 ' / Clear response with Gilinsky's Office prior to dispatch. / ..C AUAGNED TO DATE INFORMAtloN ROJTtPF!. __Denton. HitR 8-18-83 Dircks 5. Thompson _Snyder._TMIP0 _8/18/83 Roe 6. ' Grace Rehm j Stello Denton/ Case PPAS il. Eisenhut c 2. Vollmer ( D. Mattson SECY S3-2181 T 1 '4,_ Speis NR FORM 732 EXECUTIVE DIRECTOR FOR OPERATIONS 5 PRINCIPAL CORRESPONDENCE CONTROL l b x,, 3 li ; I e m 8 s e m m a L t ii s S M o 5 g e s 2 u a 8 f o F L s li <g M m e
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r- ....t ;, e' x R. D. #5 York, PA 17402 August 12, 1983 Victor Gilinsky, Commissioner U.S. Nuclear Regulatory Commission Washington, D.C. 20555 In rei Three Mile Island Unit 2 Cleanup
Dear! ommissioner Gilinsky:
C I understand that GPU Nuclear is considering making changes to the Unit 2 reactor building ventilation system in order to reduce airborne contamination and surface recontamination'(NRC/TMI-83-048, Weekly Status Report for July 24-July 30, 1983). I am very much concerned due to the fact that-the venting of the containment is continuous now -- even over weekends. We know that the containment building has proven toee very difficult to decontaminate. I would like to know if the change in the ventilation system will cause more radioactivity to be vented into the atmosphere? Sincerely, OneLw Alice A. Herman n e n,,,-,,n t - D '] V D / b U 2 ' l -}}