ML19340E647
| ML19340E647 | |
| Person / Time | |
|---|---|
| Site: | Bailly |
| Issue date: | 12/18/1980 |
| From: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Shorb E NORTHERN INDIANA PUBLIC SERVICE CO. |
| References | |
| NUDOCS 8101150225 | |
| Download: ML19340E647 (2) | |
Text
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'4 UNITED STATES l
' 'r, NUCLEAR REGULATORY COMMISSION i
(,
'E REGION lli o
799 ROOSEVELT ROAD Yg o
GLEN ELLYN,1LLINOIS 60137 1
December 18, 1980 l
I Gentlemen:
The enclosed IE Supplement No. 4 to Bulletin No. 80-17 is forwarded to you for information. No written response is required.
If you desire additional information regarding this matter, please contact this office.
Sincerely, i
Ty,,, :. 's i g,y L.' ~
,)' James G. Keppler Director i
Enclosure:
IE Supplement No. 4 to Bulletin No. 80-17 4
i 810115 0 p6 9
Dochet No. 50-367 Northern Indiana Public Service Company ATTN:
Mr. Eugene M. Shorb Senior Vice President 5265 Hohman Avenue Hammond, IN 46325 cc w/ enc 1:
Central Files AD/ Licensing AD/ Operating Reactors PDR Ljcal PDR M. SIC TIC Dean Hansell, Office of Assistant Attorney General
lh SSIMS No.:
6820
't Accessicn No.:
~
8006190074 481ITED STATES IE8 80-17 Sup. 4 PUCLEAR REGULATORY C0pWISSION O
OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
20555 December 18, 1990 t
~
IE Supplement 4 to Bulletin No. 80-17:
FAILURE OF CONTROL RODS TO INSERT DURING A SCAAM AT A BWR dg NRC staff evaluatian of failures of the continuous monitoring system (CMS)
)T for the scram discharge volume (SDV) at an operating BWR has identified the i
need for licensee actions in addition to those requested by IEB 80-17 and Supplements 1-3.
The purpose of these actions is to provide assurance that
'4 the CMS has been tested to demonstrate operability as installed, remains operable during plant operation, and is periodically surveillance tested to y
demonstrate continued operability.
y M@
The occurrence of CMS failures at Dresden Nuclear Power Station was discussed in IE Infomation Notice 80-43, which was issued on December 5,1980 to those 9
operating 8WR's with CMS recently installed.
Subsequently, investigation into the cause of the failure to receive the alarm with the 50V essentially full d~
revealed several items which required correction, including:
n 1.
Excess portions of transducer cable were placed in physical positions ep which would increase external noise sensitivity.
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2.
The UT transducers were not placed in a physical position to optimize
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system sensitivity.
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3.
A certain amount of " cross-talk" was occuring between redundant trans-4 ducers located a few feet apart on the same run of 4" pipe.
Station and vendor personnel shortened and rerouted transducer cables to improve y
noise rejection.
Vendor specialists optimized transducer placement and 6
synchronized both transducers to the same ultrasonic instrument internal clock to minimize cross-talk and improve signal to noise characteristics.
Following these actions the CMS appeared to function properly.
Further difficulties were encountered when apparently minor quantities of water leaked into the SDV as a result of control rod drive scram valve maintenance activities and minor scram outlet valve leakage.
It appears that the trans-ducers are located on a section of 50V piping which forms a local low point.
Accordingly, small amounts of water can accumulate to a depth which triggers 1
the high level alarm (at 1-1/4") before the water drains to the instrument volume. The licensee in conjunction with the NSSS vendor, performed a unit r
specific analysis for a conservative t- -
point to 2-1/2".
The system now appe alarm time del n was also installed e
n DUPLICATE DOCUMENT p.
Entire document previously 5
entered into system under:
ANO 90%196 c)7' No. of a es:
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