ML20245L191
| ML20245L191 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 08/14/1989 |
| From: | Parker T NORTHERN STATES POWER CO. |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8908220026 | |
| Download: ML20245L191 (2) | |
Text
__
[.
g
{
Northem States Power Company 414 Nicollet Mall L
Minneapolis, Minnesota $5401-1927 Telephone (612) 330-5500 August 14, 1989 Director of Nuclear Reactor Regulation U S Nuclear Regulatory Commission Attn:
Document Control Desk Washington,. DC 20555 PRAIRIE ISLAND NUCLEAR GENERATING PIANT Docket Nos. 50-282 License Nos. DPR-42 50-306 DPR-60 Supplemental Information Related to NRC Audit of Westinghouse Median Sicnal Select Signal Validation The Westinghouse Electric Corporation implementation of Median Signal Select (MSS) signal validation for narrow range steam generator level was audited by the NRC in the Westinghouse offices on July 13 and 14, 1989.
Information related to median signal select design control and surveillance testing was requested by the NRC Staff during the audit exit meeting. The following information is provided in response to that request.
Until the feedwater control system upgrade modification is closed out for both units, control configuration changes (including setpoints) to the median signal select function will only be made with the review and approval of Westinghouse.
Following closeout of the feedwater control system upgrade modification for both units, this review and approval will be performed internally or by Westinghouse.
Independent of who performs the review and approval of the changes, all pre-installation and post-installation testing to verify the operability of the median signal select function will be consistent with the testing performed by Westinghouse as part of the original design certification.
For the purposes of design control, the " median signal select function" is interpreted to include signal quality checks (i.e., delta checks and bad quality checks) associated with the actual selection of the median level channel.
The median signal selector on the steam generator narrow range level channels represents an acceptable means of satisfying IEEE 279 protection / control interaction criteria, but is considered only a control function. While control instrumentation testing is performed on a refueling basis at Prairie Island, as a matter of prudency, it is our intent to demonstrate the proper operation of the median signal select function by verifying operability during periodic surveillance of the level channel trip functions, presently performed monthly.
8908220026 890814 hi PEWR ADOCK 05000282 I"
P PDC
' l
7
+: -
b T. 4 g v7: E 4
. Director. of: NRR -
Northem States Power Company -
ic August 14,.1989' Page 2:
~
. Operability of the_ median signal select function will be demonstrated by
' verifying that the " failed" channel (channel under test) is not selected as
~ he channel for-use~in level control. This' testing will be performed for a t
-period of not'..less than one year following completion of the installation of the median signal' select-function on the associated unit.
Please. contact us_if'you have any further questions related to median signal
. select design control and testing, o
b:
Thomas M Parker:
Manager Nuclear Support Services c: Regional Administrator - Region III, NRC Senior. Resident. Inspector, NRC FRR Project Manager, NRC G Charnoff p:
_ _ _ _ _ _ _ _ _ _ _ _ _ _. _