ML17263A649
| ML17263A649 | |
| Person / Time | |
|---|---|
| Site: | Ginna  |
| Issue date: | 05/11/1994 |
| From: | Newton R WESTINGHOUSE OPERATING PLANTS OWNERS GROUP |
| To: | Thadani A Office of Nuclear Reactor Regulation |
| References | |
| GL-93-04, GL-93-4, OG-94-46, NUDOCS 9405190190 | |
| Download: ML17263A649 (13) | |
Text
ACCELERATED DILUTION DEMONSTRATION SYSTEM E
REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)
ACCESSION NBR:9405190190 DOC.DATE: 94/05/11 NOTARIZED: NO DOCKET FACIL:50-244 Robert Emmet Ginna Nuclear Plant, Unit 1, Rochester G
05000244 AUTH;NAME AUTHOR AFFILIATION NEWTON,R.A.
Westinghouse Operating Plants Owners Group RECIP.NAME RECIPIENT AFFILIATION THADANI,A.C.
Associate Director for Inspection
& Technical Assessment (P g
SUBJECT:
Forwards WOG 940426 ltr transmitting results of rod control sys testing at Ginna Station,per GL 93-04,as committed to during 940309 WOG/NRC meeting.
DISTRIBUTION CODE:
A030D COPIES RECEIVED:LTR J ENCL /
SIZE:
TITLE: Generic Ltr-93-04-Rod Control System Failure 6 Fzthdrawal of Rod Cont S
NOTES:License Exp date in accordance with 10CFR2,2.109(9/19/72).
05000244 RECIPIENT ID CODE/NAME JOHNSON,A INTERNAL: NRR/DRCH/HICB NRR/DSSA/SRXB EXTERNAL: NRC PDR COPIES LTTR ENCL 1
1 1
1 1
1 1
1 RECIPIENT ID CODE/NAME NRR DRPW PDIV-1 FIL 01 COPIES LTTR ENCL 1
1 1
1 D
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NOTE TO ALL"RIDS" RECIPIENTS:
D D
PLEASE HELP US TO REDUCE WASTE! CONTACT THE DOCUMENT CONTROL DESK, ROOM P 1-37 (EXT. 20079) TO ELIMINATEYOUR NAME FROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEED!
TOTAL NUMBER OF COPIES REQUIRED:
LTTR 6
ENCL 6
1
'9 VC::h&
Westinghouse Owners Group Domestic Utilities American Becbtc Power Carolina Power & Ught Commonwealth Edison Consolidated Edison Duquesne Ught Duke Power OG-94-46 May 11, 1994 Georgia Power Rorida Power & Ught Houston Ughting & Power New York Power Authority Northeast UQities Northern States Power Pacific Gas & Etectric Public Senrice Bectrlc &Gas Rochester Gas & Electric South Caroina Electric & Gas Southern Nuclear Tennessee Valley Authority TU Bectric Union Electric Virginia Power Wisconsin Bectrlc Power Wisconsin Public Senrice WollCreek Nudear International Utilities 8ectrabel Kansal Etectric Power Korea Electric Power Nudear Electric pic Nukieama Elektrana Spanish Utifrties Taiwan Power Vattenfall Mr. Ashok C. Thadani Associate Director for Inspection and Technical Assessmcnt Office of Nuclear Reactor Regulation=
U.S. Nuclear Regulatory Commission Washington, DC 20555
Subject:
Westinghouse Owners Group Information on Generic Letter 93-04 Demonstration Plant Testin and Utllit Surve
References:
1)
NRC Generic Letter 93-04, RRod Control System Failure and Withdrawal of Rod Control Cluster Asscmblics, 10 CFR 50.54(f),n issued June 21, 1993.
2)
OG-94-38, "Transmittal of Results of Rod Control System Testing at Ginna Station",
issued April 26, 1994.
Dear Mr. Thadani:
The WOG Program for the resolution of Generic Letter 93-04, RRod Control System Failure and Withdrawal of Rod Control Cluster Assemblies, 10 CFR 50.54(f)", Reference 1, developed a modified timing sequence to the Rod Control System.
The modified timing was tested at the Ginna Station on April 14 8& 15, 1994.
During the WOG/NRC meeting on March 9, 1994, thc WOG committed to send thc NRC a copy of the summary of the rod control testing at the Ginna Station.
The WOG letter summarizing the Ginna Station Rod Control Testing, Reference 2, is attached.
This letter also includes thc results of thc informal survey conducted by the WOG to ascertain the typical utility time period for implementation of the rccommcndcd RCS timing changes.
A majority of the WOG Utilitics responded to the survey.
Based on the survey responses, those utilitics intending to implement both the current order timing changes and the new surveillance identified the refueling outages scheduled for 1995 or carly 1996 as the typical implementation time period.
Should you have any questions regarding this letter, please contact me at (414) 221-2002.
Very truly yours, Roger A. Newton, Chairman Westinghouse Owners Group RAN/dac i
9405190190..94051 1,.
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ce: Thomas W. Alexion, USNRC (1I 1A)
'Martin J. Virgilio,USNRC (1L,1A)
Robert C. Jonesgr, USNRC (1L,1A)
Westinghouse Owners Group Steering Committee (1L)
Westinghouse Owners Group Primary Representatives (1L)
Westinghouse Owners Group Systems and Equipment Engineering Subcommittee (1L)
C.K McCoy, Georgia Power (1L)
J.P. O'Hanlon, Virginia Power (1L)
N.J. Liparulo, W (1L)
KJ. Voytcll, W (1L) 94JDCOS.WPS
eyer Westinghouse Owners Group Domestic Utilities Amencan Etectnc Power Carolina Power & Ught Commonwealth Edison Consolidated Edison Ouqueene Ught Ovke Power Georgia Power Ftonda Power & Ught Houston Ugheng & Power New York Power Authcnty NOrtheaet Utiktiea Nonhern States Power Pacitic Gas & Electric Puhtic Sennce Electnc & Gas Rochester Gas & Bectnc Scuth Carctina Beotno & Gaa Southern Nuclear Tennessee Vahey Authonty TU Bectnc Union Bectnc Virginia Power Wsconsut Etectrc Power tydocnern Pu&C SennCe Welt Creek Nuclear International Utilities Bectraoel Kansar Bectnc Power Korea Becuc Power Nuclear Etectrc P c Nuldearna Elekuana Scanreh Utietiee Taiwan Power Vattenlae OG-94-38 April 26, 1994 To:
Subject:
Westinghouse Owners Group Primary Representatives (1I1A)
Westinghouse Owners Group Transmittal of Results of Rod Control S stem Testin at Glnna Station
References:
1)
WOG-93-172, "Transmittal of WCAP-13864 'Rod Control System Evaluation Program, September 24, 1993'MUHP-6001)," issued September 24, 1993.
2)
WOG-94-048, "Transmittal of Recommended Rod Control System Surveillance Test (MUHP-6002)," issued April 8, 1994.
This letter provides a summary of the results of testing performed at the Ginna Station as part of the WOG Rod Control Enhancement Program, MUHP-6002, and to describe final resolution of this issue.
Following the testing performed in February at the South Texas Project, the Rod Control System timing was further modified. The Ginna Station volunteered to test the new timing at the completion of their refueling outage.
On April 14, 1994, the Ginna Logic Cabinet slave cycler decoder circuit cards were replaced with decoder circuit cards modified to the new timing values.
Following the card replacement, slave cycler current order traces were recorded to verify that the timing was correctly modified.
These traces were taken with the reactor trip breakers open.
Figures 1 and 2 are examples of slave cycler traces with the new timing incorporated.
On April 15, the remaining rod tests were performed with the reactor trip breakers closed.
A "fault" test was performed to verify that the new current order timing prevents rod withdrawal when failures similar to those that occurred during the Salem event are present. A verification test was performed to ensure that the new timing has no adverse effect on normal rod motion.
The fault test verified that when a Salem-type circuit failure occurs, the modified Rod Control System response is to insert all rods selected for motion when motion is requested.
(Salem-type faults produce corrupted current orders by directing that insertion and withdrawal current orders be produced simultaneously.)
The fault testing consisted of performing the following steps on each bank of rods:
1.
The signal that directs the slave cycler decoders to produce withdrawal current orders (the UPSPX signal) was purposely grounded and then outward motion was requested.
As expected, normal withdrawal current orders were produced and all rods in the bank withdrew.
2.
With the UPSPX signal grounded, inward motion was requested.
Corrupted current orders were produced and as expected, all rods in the bank inserted.
3.
The UPSPX signal ground was removed and the signal that directs the slave cyclers to produce insertion current orders (the DNSPX signal) was grounded.
Outward motion was requested.
Corrupted current orders were produced and as expected, all rods in the bank inserted.
4.
With the DNSPX signal grounded, inward motion was requested.
As expected, normal insertion current orders were produced and all rods in the bank inserted.
CRDM coil current traces for each of these steps were recorded.
Figure 3 is an example trace taken with the corrupted current orders present during rod insertion.
The verification test ensured that, with no circuit failures present, the response of the Rod Control System with the modified timing is to produce normal rod motion.
The verification testing consisted of withdrawing and inserting each bank of rods for 12 steps and recording CRDM coil current traces.
Figures 4 and 5 are examples of normal withdrawal and insertion coil currents.
Due to a safety injection pump operability problem delaying plant startup, these tests were performed at a reactor coolant temperature of 340F, with confirmatory traces at 550'F taken later during rod drop testing.
The confirmatory traces verified that there was no difference in CRDM response at the lower temperature.
With the successful completion of tests at Ginna, the work remaining consists of the following:
Review and distribute the Technical Bulletin that provides instructions on how to modify the Rod Control System timing, drawing revisions, and a generic 50.59 safety evaluation.
Revise and distribute WCAP-13864, "Rod Control System Evaluation Program," to provide the assessment of current order circuit failures with the new timing installed.
These packages will be distributed before the end of June, 1994.
Reference 1 proposed two options to address this issue. Ifyour utility has decided to use the option with the timing modification, it is recommended that the timing modification be incorporated during the first available refueling outage starting January 1995.
Reference 2 provided the recommended Rod Control System surveillance test to ensure no failures exist in the Rod Control current orders.
Due to a number of inquiries, a point of clarification is needed:
the timing values provided on pages A-9, B-11, and C-11 are for the new current order values, i.e., after the incorporation of the timing modification.
Plants that perform this surveillance prior to incorporating the modification should use the timing values provided in their Rod Control System instruction manuals.
For further information on this subject, please contact Steve Fowler at (412) 374-6071.
Very truly yours, Bryce Shriver, Chairman Westinghouse Owners Group Systems & Equipment Engineering Subcommittee BS/dc Attachments WOG Steering Committee (1L, 1A)
WOG Regulatory Response Group (1L, 1A)
Analysis Subcommittee Representatives (1L, 1A)
Systems & Equipment Engineering Subcommittee Representatives (1L, 1A)
Licensing Subcommittee Representatives (1L, 1A)
C.K McCoy, Georgia Power (1L)
J.P. O'Hanlon, Virginia Power (1L)
NJ. Liparulo, W (1L)
KL Voytell, W (1L)
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