ML20247K984
| ML20247K984 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 07/25/1989 |
| From: | William Cahill TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| CP-87-128, TXX-89474, NUDOCS 8908010113 | |
| Download: ML20247K984 (2) | |
Text
m e
L l?
i Log # TXX-89474
.~
File # 10110
~
~-"
"~~~
908.3
.Ref. # 10CFR50.55(e)
L 7UELECTRIC waren s.cahm,Jr.
"^
Execuine Vke President g
U. S. Nuclear Regulatory Commission l
Attn: Document Control Desk
['
Washington, D. C.
20555 L
[
SU8 JECT:
COMANCHE PEAK STEAM ELECTRIC STATION (CPSES)
DOCKET NOS. 50-445 AND 50-446 LOSS OF CONTROL POWER INDICATION SDAR:
CP-87-128 (SUPPLEMENTAL REPORT)
Gentlemen:
On January 6,1988,.TU Electric notified the NRC by letter logged TXX-88032
. that the deficiency involving a lack of provisions to continuously monitor the emergency diesel generator auto start. circuitry, and certain other 120 VAC and 125 VDC circuits, for a loss of power, was deemed reportable.
The last report on this issue logged TXX-89231, dated April 28, 1989, indicated that TV l
Electric was reevaluating the significance of this issue. Thc. purpose of this report is to provide the results of this re-analysis, revise the previously discussed corrective action and revise the previous conclusion of deportability pursuant to 10CFR50.55(e) to not reportable.
As indicated in TXX-88032, during design validation of the elementary diagrams for the 118 VAC static uninterruptable power supply (UPS), it was discovered that certain auto-start diesel generator circuits and other 120 VAC and 125 VDC circuits were not continuously monitored for power on the circuit.
This capability was initially viewed as a requirement of IEEE 308-1974 "IEEE. Standard Criteria for Class IE Power Systems for Nuclear Power Generating Stations."
The evaluation and reevaluation of this issue focused on those 118 VAC and 125 VDC circuits containing normally de-energized components, such that a loss of power on that circuit would not be readily apparent unless a " power available" indication was provided.
Based on a reevaluation of the requirements of IEEE 308, it has been concluded that the standard does not require' continuous " power available" indication at the individual circuit levels. The standard requires a combination of design features and surveillance requirements to ensure that the Class IE power systems remain in
.a condf ion capable of performing their intended safety functions. Sections 6.3 (1) and (2) (Surveillance Requirements, Periodic Equipment Tests) of IEEE 308 require that " Tests shall be performed at scheduled intervals to:
sposO10113 890725 h
I PDR ADOCK 05000445 1
s FDC
( p 400 North Olive Street LB 81 Dallas, Texas 75201
o j,;. M*
L TXX-89474 July 25, 1989 Page.2,of 2
/
(1)
Detect the deterioration of the equipment toward an unacceptable 1 condition.
-(2)
. Demonstrate that standby power equipment and other components that 3
are not exercised during)?rmal operation of the, station are operable."
FSAR; commitments' relative to compliance.with IEEE 308-indicate that "8.3.1.2.1.10...Surve111ance of Class IE systems indicates readiness to perf_o.rm'their intended safety function. Availability and ' operability of these systems are monitored by means of periodic testing..."
The reevaluation of this issue has ensured that periodic surveillance procedures planned for use at CPSES are adequate to demonstrate operability of those circuits that were of concern. As a result, the requirements of IEEE 308 and the CPSES FSAR have been satisfied and there is no safety
. significance associated with not providing continuous " power available"~
indication. -Consequently, the criteria for deportability pursuant to -
10CFR50.55(e) has not been met.
The corrective action discussed by-previous reports (logged TXX-88274 dated March 7 1988 and TXX-88032) was to include the addition of " power available" indication by Design Change Authorization (DCA) 62876 (previously incorrectly
. identified as DCA 63413, as logged in TXX-88274). This DCA is no longer a required corrective action and the indicated modifications have been placed in a " plant enhancement" category for future consideration.
'This completes'the evaluation of this issue.
Records supporting identification of applicable circuits and associated surveillance test l
procedures are available for NRC inspectors review.
Sincerely, 4
111am J. Cahill, Jr.
I FAM/ddm
)
c - Mr. R. D. Martin, Region IV i
Resident Inspectors, CPSES (3) l
.____ ___- - _ _