ML19220B595
| ML19220B595 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 04/12/1977 |
| From: | Arnold R Metropolitan Edison Co |
| To: | O'Reilly J NRC Office of Inspection & Enforcement (IE Region II) |
| Shared Package | |
| ML19220B594 | List: |
| References | |
| GQL 490, GQL-0490, NUDOCS 7904270069 | |
| Download: ML19220B595 (2) | |
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,,-, -m METROPOLITAN EDl50N COMPANY suse:cun or censm.=usucununss ccmuncu
' CF:lCE B0). 542 REACINC, PENNSYLVANI A 196c3 TELE?HCNE 215 - 929-601
- n.,. c_ _.a., _yii GG.L Oh90 Mr. J. P. O'Feilly, Director U. S. Nuclear Regulatory Cc=nission Office of Inspection & Inforcenent Region I 631 Park Avenue King of Prussia, Pennsylvnt"a 19406
Dear Sir:
Three Mile Island Nuclear Station Unit 2 (T.C-2)
License No. C??R-66 Docket No. 50-320 Reacter Vessel Skir Ventilacien on March 14, 1977, Mr. J. Z1sasser of your office was verbally notified of a situation which Metropolitan Edisen Cc=pany considered to be reporrable in accordance with the requirenents of ICCFR50.55(e).
This letter constitutes the required thirty-day follow-up letter.
Descrirtien The installed Reac:c: Suilding EVAC due:1:g that supplies cooling air Oc the Reacecr Vessel Suppor: Skirt has been fcund, in final checking of design calcu-latiens, to have greater pressure drop icsses than were anticipated at the cine of initial calcula:1cn and conceptual design.
The present cm di:1cn would.
have resulted in a flow of ecoling air insufficient to assure that the Reac:cr vessel Support Skir: veuld be cooled enough to preclude the tenperature of the supporting concrete frc= exceeding 1500F.
Analysis of Safety In:lications Eigh tempera:ures of the Reacecr Vessel supporting concrete could cenceivably, over a 1cng period of tine, de;rade the strergth of the concrete.
"'his cc.ndi:1cn, hcvever, veuld have been dis: overed during the startup and test phase of the project and corrected lcng before any concrete degradation vould hav2 been pessible.
Therefore, there would have been no adverse effect en the health or safety of the public cr plant staff.
Cor ective Acticn The H7AC Syste= is being re-designed to provide adequate eccling.
The re-design utilizes a pair of 15 horsepcwer nc: cts and direct driven centrifugal bicwers to 80 268 7904270667
Mr. J. ?. 0'2eilly GEL Ch90 cec 1 this space.
Only cue blever need be operated :o give the required 16,000 cf= air ficv.
The air is blean directly into the center of :he Reactor Vessel skir: using the esisting 3 foot square penetration in the prd-'ry shield.
The cooling air the.: passes through the esisting ventilation holes in the skirt and rises through the annular space inside the prd ' y shield in the manner origi-cally designed.
The new pienu that ducts the bicwer discharge into the opening in the prd-ary shield has a cocr that retains the capability of rapid access to the skirt area.
Modifications will be fully i=plemen:ed prior :o Fuel Leading presently scheduled for October 1977.
Te=porary blowers will be used if necessary during Hot Functional Tests to =aintain proper te=peratuzes.
Very truly yours, 0
'hW R. C. Arnold Vice President O.d a. *T.C. A.&.e
.wn.w.
cc: Dr. Ernst Volgenau, Director Office of Inspection & Enforce =ent U. S. Nuclear Regulatory Cc~dssion
'4ashington, D. C.
20555 80-269