ML19261E945
| ML19261E945 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 06/19/1973 |
| From: | Bernero R, Danielle Sullivan US ATOMIC ENERGY COMMISSION (AEC) |
| To: | Ippolito T US ATOMIC ENERGY COMMISSION (AEC) |
| References | |
| NUDOCS 7910170997 | |
| Download: ML19261E945 (4) | |
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JUN 1 g 373 Docket No. 50-239 T. Ippolito, Chief. Electrical Instrumentation & Control Branch, L SIMMRY OF SITE VISIT MADE TO THREE MILE ISI.AND NUCLEAR STATION, UNIT 1 Enclosed is a report of a site visit made to Three Mile Island Nuclear Stnion, Unit 1 on June 4,1973. An attendance list is also enclo<ed-D. Sullivan Design Standards Branch Directorate of Regulatory Standards R. M. Bernero, Project Manager Pressurized Water Reactors Br. No. 4 Directorate of Licensing
Enclosures:
DISTRIBUTION 1.
Site Visit Summary Docket File 2.
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REPORT OF SITE VISIT THREE MILE ISLAND l,UCLEAR STATION-UNIT 1 DOCKET NO. 50-289 JUNE 4, 1973 The site was visited on June 4, 1973 to review the installed protection and emergency power systems.
The site was visited previously for this purpose by H. Schierling, S. Folsca and D. Sullivan on March 9,1972 (Reference Sullivan to Moore Memo-to-File, dated March 17,1972).
Summary of Outstanding Items
- l.
Several lighting fixtures of questionable seismic integrity are suspended directly over tha station batteries. We were issured that the fixtures will be relocated.
- 2.
Proper separation of instruments, cables and impulse lines to be located in containment could not be verified since none of this equipment is yet installed.
S. Folsom stated that RO will follow-up on this item.
3.
The terminal boards for the cor trol room consoles are mounted (vertically) below the control rocm in the ceiling area of the cable spreading room.
These terminal boards are open to the cable spreading room but are out of reach since they are mounted some 12 feet above the floor. However, I agree with S. Folscm, who identified this problem, that open t.oards for such vital systems are not in accordance with good engineering practice.
I recommend that the applicant be requested to provide adequate enclosures for these boards.
4.
To provide " clean" isolated power for the low-level counting instruments, the applicant has installed a motcr-generator set equipea witn a flywheel.
This equipment is mounted in one of two adjecently-located 480 volt ESF switch gear rooms with the flywheel aimed at vital equipment in both rocms.
The rooms are separated by thin sheet steel.
I recommend that cnis matter be corrected.
Discussion Our review of the installed systems indicated that the other three deficiencies uncovered during the first site visit have been resolved:
1.
The cabling between the control room and cable spreading area appears to have had proper QA control in terms of physical separaticn.
2.
The ESF signal cables are properly routed to their amolifier-bistable cabinets in three separated conduits and are properly color coded.
3.
The four scram breakers and their respective trip circuit wiring (four wires-four conduits) are adequately separated.
- Remain outstanding from previous site visit.
8 07
_2_
During the meeting, the applicant was requested to address in an amendment, the Oconee scram breaker trip circuit design (faulty UV relays) in terms of assuring us that the specific proolem at Occnee would not present a potential for common mode failure at TMI. The applicant agreed.
S. Folsom identified a wiring problem several months ago involving pre-cut cables which were, in fact, too long. The extra length resulted in violations of separation criteria.
Seth believes that the applicant is proceeding properly in correcting this deficiency.
I concur.
We reviewed the feeder breaker (to the emergency buses) control circuit drawings to assure that these circuits are redundant in terms of isolating tne diesels frt,1 the offsite network under accident conditions.
We observed no deficiencies.
The drawings for the interlocks in the valve control circuits for hi-low pressure system isolation were not available. This remains an outstanding drawing review item.
We discussed two other items. We informed the applicant of problems with motor staters at Duane Arnold. The applicant will determine if starters of the same type are used at TMI.
S. Folsom agreed to follow-up on this. Also, the matter of the RHR sucti n valves (two in series) not meeting the single failure criterion was discussed briefly.
I agreed to seek guidance from Reactor Projects.
1483 308
s ATTEflDA'lCE LIST T NE 4, 1973 Atomic Energy Comission-D. Sullivan, 05 E. Marinos, DL L. Er.gle, DL S. Folsom, R0-1 General'Public Utilities D. Reppert Gilbert W. Sailer V. Willems P. Shipper 1483 309
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