ML20084R434
| ML20084R434 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 04/25/1975 |
| From: | Stephenson B COMMONWEALTH EDISON CO. |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| Shared Package | |
| ML20084R438 | List: |
| References | |
| 276-75, RO-50-249-75-19, NUDOCS 8306150114 | |
| Download: ML20084R434 (3) | |
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Chicago. Illinois 60690 BBS Ltr. #276-75 Dresden Nuclear Power Station R. R. #1 Morris, Illinois 66450 April 25, 1975 g\\1D A
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h, N ' / 4 '/,'., [Q:g Mr. James G. Keppler,. Director
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v a, REPORT OF AENORMAL OCCURRD!CE PER SECTION 6.6.A 0F THE TEE
SUBJECT:
SPECIFICATIONS BROKDi TEST LINE ON PENETRATION X-105 D
References:
- 1) Regulatory Guide 1.16 Rev. 1 Appendix A
- 2) Notification of Region III of US NRC Telephone P. Johnson, 1445 hours0.0167 days <br />0.401 hours <br />0.00239 weeks <br />5.498225e-4 months <br /> on April 17, 1975 Telegram:
J. Keppler, 1545. hours on April 17. 1975
- 3) Drawing Number: M-95 Report Number: 50-249/75-19 Report Date: April 25, 1975 Occurrence Date: April 16, 1975 Facility: Dresden Nuclear Power Station, Morris, Illinois IDDTPIFICATION OF OCCURRENCE On April 16, 1975 at 2100 hours0.0243 days <br />0.583 hours <br />0.00347 weeks <br />7.9905e-4 months <br />, it was discovered that the leak test line to the bellows seal for the drywell penetration X-105D had broken off. This occurrence represents a condition which if uncorrected could conceivably have prevented or degraded the performance of the intended safety function of an engineered safety feature system.
l CONDITIONS PRIOR TO OCCURRDiCE l
At the time of and prior to the occurrence, Unit #3 had been shutdown for refueling.
Personnel were in the X-area for the purpose of leak testing the main steam isolation valves (MSIV's). The reactor modo switch was in the
" Shutdown" position.
8306150114 750425 PDR ADOCK 05000249
'lMf S
. James G. K;ppl
) April 25, 1975 iiESCRIPTION OF OCCURRENCE At about 2100 hours0.0243 days <br />0.583 hours <br />0.00347 weeks <br />7.9905e-4 months <br /> on April 16, 1975, while making preparations for leak testing the MSIV's, a break was discovered in the " stainless steel test line to the belows seal for penetration X-105D. This is the "D" main steam line penetration.
The break location was just before the test line enters the rear bellows seal.
The line had completely separated. At the point of separation the line was somewhat flattened.
DESIGNATION OF APPARE:7P CAUSE OF OCCUP ECE (Personnel Error)
Apparently the break was due to personnel using the penetration to stand on thile conducting maintenance in the X-area. Thed"tettlinecouldhavebeen inadvertently stepped on and broken if the penetration was used in this manner.
ANALYSIS OF OCCURRENCE This occurrence in no way jeopardized the safety and health of the general public or plant personnel. Subsequent to the line repair, another leak test was performed with zero leakage results. This indicated that at the time of the occurrence, the bellows itself was intact, thus preventing a depressurization cf the d f.cIl thrcush this pcnctrction.
Aleaktestwasconductedtodeterminetheleakagethroughthed"line. The leakage was approximately 364 scfh. However, it must be remembered that the tubing at the break was somewhat crimped. Thus had the inside bellows failed, the actual leakage from the penetration would have been considerably less than that measured.
At the time of the occurrence, the secondary containment was intact and the standby gas system was capable of handling 4000 CPA flow. Thus, no uncontrolled release from the secondary containment would have occurred.
CORRECTIVE ACTION Since the unit was shutdown, cooled down, and depressurized, there was no need for any in: mediate corrective action other than issuing a work request to
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initiate needed repairs.
The break was repaired on April 22, 1975. The broken piece of tubing was removed by grinding. New stainless steel tub'ing was then fitted to the sock-O-let and welded in using approved procedures. After the repair was completed, a satisfactory leak test was condteted with zero leakage.
To prevent this type of failure in the future, grating shall be installed in the X-area to prevent personnel from standing on the main steam line penetrations.
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ffr.JkmesG.Kipp1t April 25,-1975 g
FAILURE DATA The line that failed was made of " stainless steel tubing.
A failure of the test line to the bellows seal for penetration X-105C on Unit #2 was discovered on December 12, 1974.
$4MP Superintendent BBS:HJH:smp File /NRC e
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