ML19261F369
| ML19261F369 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 12/08/1977 |
| From: | Herbein J METROPOLITAN EDISON CO. |
| To: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| GQL-1699, NUDOCS 7910250833 | |
| Download: ML19261F369 (3) | |
Text
Cb7Ai+Lfist
/
i l*
WM/f2;'l.]
w, n.,
/
e
/
n,
- x m
/
METROPOLITAN EDISON COMPANY sussiouavorce::sen vueucunuriesccarcuric::
F3T OFFICE BOX 542 READING, PENNSYLVANI A 19603 TELEPHONE 215 - 929-3601 December 8, 1977 GQL 1699 Mr. B. H. Grier, Director U. S. Nuclear Regulatory Commission Region 1 631 Park Avenue King of Prussia, Pennsylvania 19hc6
Dear Sir:
Three Mile Islar.d Nuclear Station Unit 1, TMI-l Response to IE Bulletin No. 77-05 Enclosed please find Metropolitan Edison's response to I.E. Bulletin No. 77-05 concerning the failure of pin and socket type electrical connectors in a post LOCA containment environment.
In light of the fact that the supplement to I.E.Bulletin 77-05 (I.E.
Bulletin 77-05A) was received by Met-Ed on November 16, 1977, and because additional analysis is required to formulate a response to that supple-ment, Met-Ed vill respond to I.E. Bulletin 77-05A by December 16., 1977 We trust this submittal to be satisfactory,- however, should you have any additional questions please contact me.
Sincerely(
s
/
J.
Nerbein Vice President JGH:RAL:tas Enclosure ec:
U. S. Nuclear Regulatory Ccmmission Office of Inspection and Enforcement Division of Reacter Ccnstruction Inspecticn Washington, D,C.
20555 1482l23 M
m osso w
Encl re to GQL 1699 Metropolitan Edison Company Three Mile Island Nuclear Station, Unit 1 I.E. Bulletin No. 77-05 Recent tests conducted by Sandia Laboratories of electrical connector / cable l
assemblies in a simulated post LOCA containment environment (LWR) demonstrated l
1 that the assemblies failed to perform in an acceptable manner. Metropolitan i
Edison Generation Engineering has reviewed the TMI-1 safety systems which cre located within containment, and therefore could be subjected to a post LOCA containment environment. These systems are as follows:
I.
Engineered Saferuards Actuated Eauinment AH-E-1A/B/C NS-V-35 IC-V2 AH-VlB/C MU-V2A/B l
MU-V25 CF-V2A/B CA-V1,3,hA/B, 13 WDL-V303 II.
Neutron Detectors B.
Reactor Coolant Pressure Transmitters C.
Reactor Outlet Temperature RTD's D.
Potential and Current Transformers for Reactor C.colant Pump Pcver Monitors E.
Reactor Coolant Flov Elements
~
III.
Enrineered Safeguards Actuation Instrumentation A.
Reactor Ccolant Pressure Transmitters n
The connecters which were tested by Sandia Laboratories, and found to be deficient ve:e of the pin and socket type,' with metal shell and screw couplings. TMI-1 does not use any pin / socket connectors for any pcVer cr -control cable connections. These _
connections are made by "hard viring" (i.e. terminal biceks, which are inside either 1
2 motor terminal boxes or GAI terminal boxes)'.
Of the safety systems listed above, pin and socket type connectors are used enly in the control rod drive mechanis:s (CREM) and in the neutron detectors. Neither the CREM nor the neutron detectors are required to operate during a LOCA.
The CRDM vill trip upon loss of pcVer initiated by a reactor trip.
It should be noted, that should a CRDM fail, it vill fail with the control rod in the safe (" inserted")
l position. Additionally, a failure of a connector en a control rod positien indicato.
vould produce a false reading which would initiate a non-safety related alarm indication.
Neutron detectors are not required to cperate during a LOCA. These detectors provide input to the Reactor Protection Syste=, as a safety system, during operaticn.
It should also be noted that the electrical connectors used in conjuncticn with these neutron detectors are manufactured by a different company than those which were tested by Sandia Labcratories.
Met-Ed therefore concludes that T'4I-1 does not utilize or plan to utilize electrical r:ennector assemblies of. the type tested by Sandia Laboratories, or any other similar (pin and socket) type, in syste=s that are located inside containment, are subject to a LCCA environ =ent and are required to be operable during a LOCA.
1482 125
.