ML20086M196
| ML20086M196 | |
| Person / Time | |
|---|---|
| Site: | Fort Calhoun  |
| Issue date: | 02/03/1984 |
| From: | William Jones OMAHA PUBLIC POWER DISTRICT |
| To: | John Miller Office of Nuclear Reactor Regulation |
| References | |
| LIC-84-033, LIC-84-33, NUDOCS 8402160414 | |
| Download: ML20086M196 (4) | |
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Omaha Public Power District 1623 Harney Omaha. Nebraska 68102 402/536 4000 February 3, 1984 LIC-84-033 Mr. James R.
Miller, Chief U.
S. Nuclear Regulatory Commission Of fice of Nuclear Reactor Regulation Division of Licensing Operating Reactors Branch No. 3 Washington, D.C.
20555
Reference:
Docket No. 50-285
Dear Mr. Miller:
Environmental Qualification of Saf e ty-Related Electrical Equipraent Limit Switches on HCV-1107B and HCV-1108B In a letter to the Commission dated September 9, 1982, the Omaha Public Power District committed to replacing the Fisher Type 304 limit switches for HCV-1107B and HCV-1108B with fully qualified NAMCO limit switches.
As was reported in a telephone conversation on January 16, 1984 between Mr.
E. G. Tourigny of your staff and Mr.
K.
J.
Morris and Mr.
J. J.
Fisicaro of the District, while up-dating the electrical equipment qualification book to reflect qualification data for Fisher 304 limit switches, it was dis-covered that Fisher 304 limit switches are still installed on the two aubject valves rather than the fully qualified NAMCO models.
The telephone conversation also referred to five other limit switches (YCV-1045, YCV-1045A, YCV-1045B, FCV-1368, and FCV-1369) whicn were omitted from replacement during the 1983 refueling out-age.
Of the seven limit switches identified on the original SCEW sheets submitted for review to Franklin Research Center, three (YCV-1045, FCV-1368, and FCV-1369) were eliminated from subsequent sub-mittals.
These three limit switches were determined to be outside the scope of the electeical equipment qualification review.
How-ever, they will be replaced during the 1984 refueling outage.
8402160414 840203 DR ADOCK 05000285 PDR q
45 5124 Employment with Equa10pportunity Male. Female I
l
Mr. James R. Miller LIC-84-033 Page Two The remaining four limit switches (on HCV-1107B, HCV-1108B, YCV-lO45A, and YCV-1045B) are subject to qualification.
These limit switches are part of the auxiliary feedwater system and are located in room 81 of the auxiliary building.
Justification for continued operation of the station until replacement of these limit switches during the next refueling outage, scheduled to begin in March, 1984, is provided in the attachment to this letter.
Sincerely,
/jdf W. C. Jones DivisiknManager Production Operations WCJ/DJM:jmm Attachment cc:
LeBoeuf, Lamb, Leiby & MacRae 1333 New Hampshire Avenue, N.W.
Washington, D.C.
20036 Mr.
E.
G.
Tourigny, Project Manager Mr.
L.
A.
Yandell, Senior Resident Inspector
Attachment JUSTIFICATION FOR CONTINUED OPERATION WITH NON-QUALIFIED LIMIT SWITCHES ON HCV-1107B, HCV-1108B, YCV-1045A, AND YCV-1045B It is the District's engineering judgment that continued interim operation of the Fort Calhoun Station until replacement of these limit switches during the upcoming refueling outage is justified.
These limit switches provide valve position indication only.
The District believes that the failure of these limit switches would not impair the operation of the auxiliary feedwater system should it be required in the event of a design basis accident (DBA).
The District believes the only area of concern regarding the po-tential failure of these switches is the pocsibility of providing false information to the operator.
The only DBA which could introduce a harsh environment in room 81 (where the switches are located) is a main steam line break out-side containment.
This accident introduces design basis environ-mental conditions of a pressure of 1.2 psi, a temperature of 216*F, and a saturated steam atmosphere in room 81.
A failure of the switches would have to be introduced by one or more of these three environmental stresses.
The switches are constructed of a cast iron body and an aluminum screw-on cover which is 0-ring sealed.
The non-metallic portions of the micro-switches are made of phenolic and fiberglass.
They are rated for 180*F continuous service.
Because of construction and materials used, it is not believed a short exposure to 216*F and 1.2 psi would adversely affect the switches' operation.
The remaining environmental concern 1:3 the saturated steam atmos-phere.
This introduces the possibility of migration of steam and/or condensate (more likely) into the switch through the cable /
conduit entrance to the switch assembly.
This raises the po-tential for shorting.
It is the District's judgment that shorting is very unlikely.
How-ever, if shorting were to occur, two things could happen.
Fi rs t,
a ground on one lead of the station battery could occur.
The other lead is protected from ground by the resistance of the in-dicating light assembly.
Secondly, both the red and the green in-dicating lights could be on.
In analyzing these possibilities and their potential effect on operator information, there is no serious concern.
Since neither a single ground nor a short causing both indicating lights to oper-ate could cause the fuses to blow, the control function would re-main intact.
This is further assured by the fact that the control solenoids are isolated and use environmentally qualified Raychem splices in room 81.
i 1
,,-. Further, a short causing both indicating lights to operate will be readily apparent to the operator.
Accident position of the valves can still be confirmed by verifying flow in the auxiliary feed-water system or by checking the steam generator level.
For these reasons, the District believes that continued operation is justific1 until the 1984 refueling outage, when these limit switches will be replaced.
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