ML20245J609
| ML20245J609 | |
| Person / Time | |
|---|---|
| Site: | Farley  |
| Issue date: | 04/24/1989 |
| From: | Hairston W ALABAMA POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 8905040198 | |
| Download: ML20245J609 (3) | |
Text
_
e Alabirna Power Company
. 40 Inverniss Center Parkway Post Office Box 1295 Birmingham. Alabama 35201 Telephone 205 868-5581 W. G. Hairston,111 Senior Vice President Nuclear Operations April 24, 1989 AlabamaPower the Southem el0CinC SYSlem Cocket Nos.
50-348 50-364 U. S. Nuclear Regulatory Commission ATTN: Document Contr,1 Desk Vashington, D. C. 20F;5 Gentlemen:
Joseph H. Farley Nuclear Plant - Units 1 and 2 Safety Related Fuse Verification Program NRC Inspection Report Nos. 50-348/87-33 and 50-364/87-33 dated January 28, 1988 document an inspection conducted by V. H. Bradford on November 17, 1987 - January 11, 1988.
Included in this report was an unresolved item regarding incorrect fuse rating.
As stated in the report:
The inspectors examined fuses removed from the circuits to solenoid valves for head vent valves 2213A, 2213B, 2214A and 2214B. These fuses had been removed on November 29, 1987 to meet TS 3.4.12 which required valves to the Reactor Vessel head vent systems to be closed and power removed when the vent systems paths were inoperative. The Reactor Vessel head vent systems were inoperative on November 29.
The inspectors noted that four of the fuses were rated at 3 1/2 amps and were of the dual element time delay type whereas the remaining 14 fuses were rated at 3 amps and were of the single element " fast fure" type.
Further investigation indicated that construction drawing Nos.
D-177300, Sheets 1 and 2, and 177394 Sheets 5 and 6 required 3 amp fuses for these circuits.
It appears that PCN B-83-1465 changed the required rating of these fuses to the 3 1/2 amp type.
However, the drawing had not yet been revised to incorporate this change.
The licensee is reviewing this item to determine why the drawings were not revised and is to review at least three other recent plant changes which resulted in fuse size changes to ascertain if these changes had been incorporated in the "as-built" design drawings.
This item was identified as Unresolved Item 348, 364/87-33-01 pending completion of the licensee's review.
On February 24, 1989, the NRC inspectors and NRC Region II supervision discussed this unresolved item with the Farley. Nuclear Plant General Manager and requested a written response from Alabama Power Company in'icating the status of this item and proposed corrective actions. NRC Ir iection Report Nos. 50-348/89-05 and 50-364/89-05 formally documented ths February 24, 1989 request.
The NRC's transmittal letter, dated March 31, 1989, specifically requested a written assessment of the extent and significance of this issue by April 28, 1989. The following information provides the requested response.
[
89050^9198h0424oOO348 PDR ADOCK NU f
g
1:
"U. S. Nuclear Regulatory Commission i
April 24, 1989 ATTN: Document Control Desk-Page 2 Vhen questioned by the NRC during the initial inspection, Alabama Power Company requested the designer (Bechtel Power Company) to evaluate the general requirements for fuse ratings in Class 1E control circuits in Farley Nuclear Plant in addition to the unresolved item identified above.
Bechtel responded by describing that the selection of a control fuse size is based on such criteria as the control fuse not blowing on normal inrush and steady current, the fuse clearing a downstream fault without tripping the upstream breaker, the fuse providing adequate protection to the downstream conductors, etc.
Based on this information, it is possible to select and use a range of fuse ratings in each application which vill meet the criteria established above. The acceptance of the fuse size and characteristics for each application is documented in design documents (e.g., domestic drawing, vendor drawing, or design change documentation).
The specific unresolved item identified above involved the head vent solenoid valves in the alternate shutdown system.
When the original control circuit was designed prior to the alternate shutdown modification, the designer developed elementary diagrams that included the 3 amp fuse sizes based on the connected load for the control circuit. The elementary diagrams did not specify fuse characteristics; however, the fuse size and characteristics (3 amp fast blev) were identified on the vendor drawings for the main control board portion of the circuit. When the alternate shutdown system was added to the plant, the designer determined that 3 amp fuses were not available, but recognized that 3 1/2 amp dual element (slow blow) fuses were acceptable and available. Consequently, a requisition specified by the designer was issued to the vendor requesting 3 1/2 amp dual element fuses that were later documented in the vendor drawings.
Therefore, Bechtel concluded in a letter dated April 27, 1988 that it is acceptable to use the fuse rating indicated either on the vendor Bill of Materials or the elementary diagrams since both were evaluated and found acceptable for the application.
Based upon the above, the installed fuses were correct.
Alabama Power Company made a conscious dedision not to revise the elementary diagrams developed by Bechtel to reflect the installed fuse sizes based on costs and the acceptability of a range ef fuses.
This decision did not apply to Southern Company Services, an independent designer for Farley Nuclear Plant. This decision has been reevaluated since certain operational and maintenance concarns result from the differences in fuse sizes specified on elementary diagrams and vendor drawings.
Several alternatives have been evaluated. Accordingly, Alabama Power Company vill prepare a fuse manual which vill supersede design drawings and manuals as the controlling document for fuses.
Concurrently, administrative controls vill be developed to establish the manual as the controlling document.
l
g-
,;. -- o.
i :;.
- C U.'S. Nuclear Regulatory Commission April 24, 1989
-ATTN: Document Control Desk Page 3-i l
l Fuse issues beyond.the scope of this unresolved item have recently.
developed _throughout the industry. As a result, Alabama Power Company-has decided to perform an evaluation of fuses installed in Farley Nuclear Plant.
To support this evaluation, an action plan that identifies specific action items, responsible party, and projected completion dates has been developed. A copy of this action plan has been provided to the NRC resident inspector for information.
g If there are any questions, please advise.
Respectfully submitted, ALABAMA POWER COMPANY YY VGH,III/ REP:mV.437 cc:
Mr. S. D. Ebneter Mr. E. A. Reeves Mr.-G. F. Maxwell
!