ML20056F174
| ML20056F174 | |
| Person / Time | |
|---|---|
| Issue date: | 08/02/1993 |
| From: | Alexion T Office of Nuclear Reactor Regulation |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| GL-93-04, GL-93-4, NUDOCS 9308260145 | |
| Download: ML20056F174 (32) | |
Text
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t UNITED STATES j
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NUCLEAR REGULATORY COMMISSION g
j WASHINGTON, D.C. 20556 0001 g*
p August 2, 1993 WESTINGHOUSE OWNERS GROUP
SUBJECT:
SUMMARY
OF HEETING ON JULY 9, 1993, REGARDING THE WESTINGHOUSE OWNERS GROUP PROGRAM PLAN TO ADDRESS GENERIC LETTER 93-04 On July 9, 1993, representatives of the Westinghouse Owners Group and various utilities (hereafter referred to as WOG) briefed the NRC staff on the WOG program plan to address Generic Letter (GL) 93-04, " Rod Control System Failure and Withdrawal of Rod Control Cluster Assemblies." Meeting attendees are listed in Enclosure 1.
Slides presented by WOG are in Enclosure 2.
WOG presented a summary of the recent events at Ginna, where, on two separate occasions, a control bank group moved out when in-motion was demanded.
WOG concluded that the Ginna events were unlike the Salem events because the slave cycler current orders were not corrupted, all rods in the group moved uniformly, urgent alarms halted automatic rod motion after one step, and the Ginna failures were intermittent.
In addition, there have been two recent rod control system malfunctions at the Point Beach plants.
In these events the rods failed to move on demand.
The NRC staff stated that we expect to be kept fully informed of any rod control system malfunctions involving rod movement or lack of rod movement.
Next, WOG presented its red control system evaluation program.
The program's purpose is to assess the historical performance of the rod control system and to determine the type of rod motion that can occur when the drive mechanisms are subjected to corrupted current orders.
WOG will conduct an industry survey, a generic failure assessment, and a test program.
W0G also presented three postulations of corrupted current orders with no resultant control rod motion.
In parallel with the rod control system evaluation program, WOG will conduct a safety analysis program to show compliance with General Design Criterion 25 either by demonstrating that no single failure can cause asymmetric rod control cluster assembly (RCCA) withdrawal or by demonstrating that specified fuel design limits are not exceeded for any postulated RCCA withdrawal.
The latter would require use of an advanced Westinghouse code (LOFT 5/SPNOVA) with 3-D core analysis capability. WOG stated that this code has received tacit approval from the Nuclear Installations Inspectorate (UK), but has not been submitted to the NRC.
The code would be used to perform generic bounding analyses of postulated asymmetric RCCA withdrawal events to demonstrate that the departure from nucleate boiling ratio (DNBR) limit is met.
WOG stated that licensees would have difficulty in assessing whether their i
licensing basis is still satisfied within 45 days of the date of issuance of rM GL 93-04, and proposed extending this part of the 45-day response until the p
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. 90-da) response.
WOG mentioned that licensees will still describe the comper.satory short-term actions within 45 days, as requested by the GL.
The NRC staff offered the following feedback at the conclusion of the meeting.
The-WOG program is well thought out and has the proper focus.
It also appears that WOG and the industry are proceeding about as fast on the GL as one could j
expect. The proposed extension on the 45-day response makes sense because (1) short-term compensatory actions are being taken, (2) the delay will not impact the schedule for long-term resolution of the issue (the 90-day response required by GL 93-04), and (3) the safety significance of this issue is not i
high. The staff suggested that WOG formally request the extension during the following week.
ORIGINAL SIGNED BY:
Thomas W. Alexion, Project Manager Project Director IV-1 Division of Reactor Projects - III/IV/V Office of Nuclear Reactor Regulation 1
Enclosures:
1.
List of attendees 2.
Slides j
DISTRIBUTION w/ Enclosure 2:
Central File NRC & Local PDRs PD4-1 Reading TAlexion ABBeach w/o Enclosure 2:
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0 90-day response.
WOG mentioned that licensees will still describe the compensatory short-term actions within 45 days, as requested by the GL.
Ti e NRC staff offered the following feedback at the conclusion of the meeting.
The WOG program is well thought out and has the proper focus.
It also appears that WOG and the industry are proceeding about as fast on the GL as one could expect. The proposed extension on the 45-day response makes sense because (1) short-term compensatory actions are being taken, (2) the delay will not impact the schedule for long-term resolution of the issue (the 90-day response required by GL 93-04), and (3) the safety significance of this issue is not high. The staff suggested that WOG formally request the extension during the following week.
&W d
Thomas W. Alexion, Project M nager Project Director IV-1 Division of Reactor Projects - III/IV/V Office of Nuclear Reactor Regulation
Enclosures:
1.
List of attendees 2.
Slides i
4
9 I
j 1
i July 9. 1993 Meetina with the Westinahouse Owners Group (WOG)
Reaardina the WOG Proaram Plan to Address Generic letter 93-04 List of Attendees F_A_M_f ORGANIZATION PHONE A
E. F. Goodwin NRC/NRR/DEAB 301-504-1154 R. A. Green NYPA 914-987-3654 C. M. Vertes Westinghouse 412-374-4481 S. K. Fowler Westinghouse 412-374-6071 N. E. Campbell NRC/NRR/ DORS /0GCB 301-504-2836 A. J. Baker M Nuclear Safety 412-374-5818 M. J. Proviano M Nuclear Safety Licensing 412-374-5651 N. F. Dudley NRC/NRR/PDI-4 301-504-1443 J. D. Campbell M WOG Project Office 412-374-6206 Bob Eliasz Rochester Gas & Electric 716-724-8075 Clair Edgar Rochester Gas & Electric 315-524-4446 X438 Lee Bush Commonwealth Edison 708-746-2084 X2890 W. R. Butler NRC/NRR/PDI-3 301-504-1434 Arland MacKinney NUMARC 202-872-1280 A. C. Passwater Union Electric 314-554-3205 Mike Schoppman Florida Power & Electric 301-652-2500 James J. Raleigh STS Inc.
301-652-2500 Jack Ramsey NRC/NRR/0EAB 301-504-1167 Angelo Marinos NRC/NRR/DRCH 301-504-2911 William H. P.uland NRC/RI/ES 215-337-5376 Hukam Garg NRC/NRR/DRCH 301-504-2929 Ron Frahm NRC/NRR/DSSA 301-504-2866 M. S. Chatterton NRC/NRR/DSSA 301-504-2889 Ashok Thadani NRC/NRR/DSSA 301-504-2884 Tom Alexion NRC/NRR/DRPW 301-504-1326 Al Johnson NRC/NRR/DRPE/PDI-3 301-504-1497 Bryce L. Shriner Virginia Power /WOG 804-273-2721 James Bailey Public Service Electric & Gas /WOG 609-339-1851 Larry Wash North Atlantic Energy Service Corp.
603-474-9521 X3347 Roger Newton Wisconsin Electric 414-221-2002 Jeffrey Bass Westinghouse Licensing 412-374-4262 John Galembush Westinghouse 412-374-5036 S. Singh Bajwa NRC/NRR/PDII-1 301-504-1013 James Stone NRC/NRR/PDI-2 301-504-1419 E. J. Weinkam FPL/ Turkey Point 305-246-7383
WOG UPDATE ON ROD CONTROL SYSTEM EVENT July 9,1993 8:30 -12:00 ROOM 2F17-21, WHITE FLINT Rockville, Md i
i I
i WOG-NRC Meeting 7/9/93:1
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AGENDA FOR JULY 9,1993 WOG/NRC MEETING ON PROGRAM PLAN ADDRESSING GENERIC LETTER 93-04 e
INTRODUCTION
SUMMARY
OF GINNA EVENT i
e GENERIC LETTER 93-04
SUMMARY
e WOG ACTIVITIES / STRATEGY e
WOG PROGRAM PLAN e
SURVEY e
TEST PLAN / FAILURE ANALYSIS e'
SAFETY ANALYSIS e
GENERIC RESPONSE TO 93-04 e
SCHEDULE e
LONG-TERM CONSIDERATIONS e
DISCUSSION ITEMS e
GDC 25 e
45-DAY RESPONSE EXTENSION e
NRC FEEDBACK o
CLOSING'r4EMARKS v
WOG NRC Meeting 7/9/93:2
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INTRODUCTION OPENING REMARKS MEETING PURPOSE
SUMMARY
OF WOG ACTIVITIES-1 WOG-NRC Meeting 7/9/93:3 i
MEETING PURPOSE TO SUMMARIZE WOG ACTIVITIES 1
TO DISCUSS THE GINNA EVENT TO PRESENT THE WOG PROGRAM PLAN AND SCHEDULE 1
TO DISCUSS GDC 25 INTERPRETATION TO REQUEST AN EXTENSION (15 DAY)
TO SOLICIT NRC FEEDBACK l
l 1
WOG NRC Meeting 7/9/93:4
SUMMARY
OF WOG ACTIVITIES i
COMPLETED TO DATE i
i 1
June 14 NRC Meeting in Bethesda, Md i
j June 16 Presentation to WOG General Session in Milwaukee, WS
)
June 24 Westinghouse / WOG Program Plan Meeting in l
Monroeville, PA I
June 25 WOG RRG Letter issued to all members outlining WOG Effort Related to Salem Rod Control System-l Event (OG-93-39) l j
June 30 Project Authorizations transmitted to WOG Utilities s
J i
July 2 WOG RRG Letter issued to all members i
outlining Generic Assessment of the Plant-I Specific Compensatory Actions Regarding i
Salem Rod Control System Event (OG-93-42) l July 7 WOG voting on Project Authorization July 9 WOG/ Westinghouse /NRC Meeting in Rockville, J
Md a
1
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WOG NRC Meeting 7/9/93:5
SUMMARY
OF GINNA EVENT e
DESCRIPTION OF JUNE 29 EVENT:
o PLANT AT 97% POWER WITH AUTOMATIC ROD CONTROL e
CONTROL BANK D GROUP 1 AT 211, GROUP 2 AT 210 e
IN MOTION DEMAND CREATED e
CBD GROUP 1 STEPPED OUT, GROUP 2 STEPPED IN e
URGENT ALARM STOPPED ROD MOTION AFTER 1 STEP e
AFTER INITIAL TROUBLESHOOTING, URGENT ALARM WAS RESET e
ROD MOTION TESTS WERE NORMAL WOG NRC Meeting 7/9/93:6
l'
SUMMARY
OF GINNA EVENT l
l DESCRIPTION OF JULY 5 EVENT:
e ROD CONTROL IN MANUAL OPERATOR PERFORMED ROD MOTION TEST FOR CONTROL' BANK D IN BANK D SELECT ON IN DEMAND, GROUP 2-STEPPED IN, GROUP 1 STEPPED OUT OPERATOR REMOVED DEMAND-AFTER 1 STEP I&C PERFORMED DIAGNOSTIC TESTS MOST PROBABLE CAUSE WAS INTERMITTENT FAILURE OF "UP" SIGNAL ALL CARDS ASSOCIATED WITH DIRECTION SIGNAL REPLACED
~
i WOG-NRC Meeting 7/9/93:7 l
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SUMMARY
OF GINNA EVENT l
(continued) l i
COMPARISON TO SALEM EVENT:
SLAVE CYCLER CURRENT ORDERS WERE NOT CORRUPTED (NORMAL IN AND OUT MOTION)
ALL RODS IN GROUPS MOVED UNIFORMALLY URGENT ALARM HALTED AUTOMATIC ROD MOTION AFTER ONE STEP i
l WOG.NRC Meeting 7/9/93:8
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GENERIC LETTER 93-04
SUMMARY
j REQUIREMENTS:
e Licensing Basis Assessment in 45 Days on:
/
Requirements for System Response to a Single Failure in the Rod Control System
/
Provide a supporting discussion in light of the information generated as a result of the Salem event e
if Licensing Basis is not satisfied:
1
/
Provide Assessment of impact of Potential Single Failure in Rod Control System on Licensing Basis of Facility
/
Describe Compensatory Short-term Actions
/
Provide Plan and Schedule within 90 days for long-term resolution WOG.NRC Meeting 7/9/93:9
-._ _-_.--__.-. ___ __...~-, ~___-
WOG ACTIVITIES / STRATEGY 9
Meeting held between Westinghouse and WOG on e
6/24 to discuss future plans for communication and other activities.
l Program Plan Developed for:
j
/
Equipment Survey l
/
Failure Analysis j
/
RCS Testing Program j
/
Safety Analysis
/
Program Integration e
WOG Letter OG-93-39 dated June 25th issued following meeting l
l
/
Program Plan and Schedule identified
/
Strategy identified i
i i
' WOG-NRC Meeting 7/9/93:10
l-WOG ACTIVITIES / STRATEGY-i i
(continued) 1 i
I 1
j e
Second WOG Letter OG-93-42 issued on 7/2/93 l
regarding:
1 e
l
/
Discussion of Salem Compensatory Actions i
/-
Further Description of Salem Rod Control e
j Signals l
/
Current Traces i
/
Copy of Salem Units 1 &~ 2 Justification for Continued Operation (JCO)
Upcoming Subcommittee Meetings
/
Analysis Subcommittee - 7/20/93
/
System & Equipment Engineering Subcommittee - 8/12/93 i
Integration of Activities (Steering Committee) j e
/
Compliance with GDC 25
'/
Guidance for licensee response
/
Long-term considerations WOG NRC Meeting 7/9/93 11 i
=_
=.
WOG PROGRAM PLAN ROD CONTROL SYSTEM EVALUATION PROGRAM i
PURPOSE OF PROGRAM:
Assess the historical performance of the Rod Control System Determine type of motion that can occur when CRDMs are subjected to corrupted current orders under varying conditions PROGRAM ELEMENTS:
industry performance review a
Generic failure assessment Test program conducted in a test facility WOG NRC Meeting 7/9/93:12
ROD CONTROL SYSTEM EVALUATION PROGRAM (continued)
INDUSTRY PERFORMANCE REVIEW:
Survey sent out to WOG utilities on 6/25/93 Collects information on Logic Cabinet failures From initial criticality to May 1993 Also collected are:
/
Operational events (stuck rods or rod misalignment)
/
Circuit modifications Data to be returned by July 15,1993 Draft report to be issued by July 23 Final report to be issued by July 30 WOG-NRC Meeting 7/9/93:13
)
ROD CONTROL SYSTEM EVALUATION PROGRAM (continued)
GENERIC FAILURE ASSESSMENT Verify the effects associated with CRDM current order malfunctions e
Determine whether other single point failures can occur that can corrupt the CRDM current orders and produce movement of less than a full group of control rods Final report to be issued by July 30 e
l WOG-NRC fi eeting 7/9/93:14
i ROD CONTROL SYSTEM EVALUATION PROGRAM (continued)
ROD CONTROL SYSTEM TEST PROGRAM:
Assembles a team of WOG, PSE&G and WEC personnel to develop detailed test plan:
4 Runs tests that will include:
/
Baseline cycle tests
/
Latching tests
/
Vertical displacement tests
/
Load tests
/
Timing tests Draft report to be issued by September 9-i e
Final report to be issued by September 24
. e <..
WOG NRC Meeting 7/9/93:15
ROD CONTROL, SYSTEM EVALUATION PROGRAM (continued) 00RRUPTED CRDM CURRENT ORDER EFFECT i
e Current orders supplied to stationary and movable coils are normal outward motion current orders l
e Current order supplied to lift coil is a combination of iriward and outward motion current orders l
l l
l l
WOG-NRC Meeting 7/9/93:16 i'
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CORRUPTED CRDM CURRENT ORDER SEQUENCE
- 1. Statiencry sr.d movable currents programmed to full i
current l-
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- 2. Lift current programmed to full current i
i Normal lift inward motion sequence j
i i
Stationary coil still still at full current i
i I
- 3. Stationary current programmed to zero current i
- 4. Lift current programmed to reduced current (normal lift
{
inward motion sequence) l
- 5. Lift current switched back to full current (normal lift outward motion sequence takes control) i i
i j
- 6. Stationary current programmed to full current l
- 7. Lift current, s ' rammed to zero current (normal lift.
j
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inward motion 83quence takes control)
{
- 8. Movable current programmed to zero current 4
- 9. Stationary current programmed to reduced current (end i
of normal motion cycle)
WOG-NRC Meeting 7/9/93:11 1
3
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POSTULATIONS ON ROD MOTION WITH CORRUPTED CURRENT ORDERS 1.
LIFT COIL LIFTS MOVABLE GRIPPER ASSEMBLY BEFORE MOVABLE GRIPPERS ENGAGE GROOVE A.
Movable grippers engage land B.
Movable grippers then slide into next higher groove C.
Rod does not lift 5/8 inch step 2.
STATIONARY GRIPPERS DO NOT RELEASE WHEN DEENERGlZED A.
Lift coil pulls on movable grippers when stationary grippers still engaged B.
When stationary coil deenergized, grippers are bound into drive rod groove C.
Lif+, coil unable to lift movable grippers 5/8 inch step i
WOG NRC Mee.ing 7/9/93:18 l
l
~.
l POSTULATIONS ON ROD MOTION I
WITH CORRUPTED CURRENT ORDERS (continued) i i
3.
MOVABLE GRIPPER ASSEMBLY DROPS DOWN BEFORE STATIONARY GRIPPERS REENGAGE A.
Lift coilis fully deenergized before stationary grippers reengage B.
Rod lifts 5/8 inch and then drops 5/8 inch 5
C.
Low probability due to delay between deene gizing the lift coil and lowering the movable gripper assembly t
WOG-NRC Meeting 7/9/93:19 r--
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WOG PROGRAM PLAN i
SAFETY ANALYSIS e
GDC 25 PROTECTION SYSTEM REQUIREMENTS FOR REACTIVITY CONTROL MALFUNCTIONS i
"The protection system shall be designed to assure that specified acceptable fuel design limits are not exceeded for any single malfunction of the Reactivity Control Systems, such as accidental withdrawal of control rods."
To show compliance with GDC 25, either:
1.
Demonstrate that no single failure (without other effects) can cause an asymmetric RCCA withdrawal or 2.
Demonstrate that specified acceptable fuel design limits are not exceeded for any postulated RCCA withdrawal event WOG-NRC Meeting 7/9/93:20 s
1
+
'I 3
O SAFETY ANALYSIS ASYMMETRIC ROD WITHDRAWAL EVENTS e
Current Codes / Methods Not Sufficient to Demonstrate that the minimum DNBR is Met for All Westinghouse-Plants in response to asymmetric rod withdrawal events Program assess the safety significance of asymmetric rod e
withdrawal events LOFT 5/SPNOVA Safety Analysis Advanced Westinghouse Non-LOCA Transient Computer Code With 3-D Core Analysis Capability Use of 3-D Core Transient Model Generates DNB Mergin Compared to Currently Licensed Methods WOG-NRC Meeting 7/9/93:21 1
- ~ - -.... - -.
SAFETY ANALYSIS LOFT 5/SPNOVA LICENSING SPNOVA Code Approved by NRC (WCAP-12394 - NRC Approved 11/26/1990)
SPNOVA Application - BEACON (WCAP-12472 - Submitted to NRC 5/90)
LOFT 5/SPNOVA Used by National Nuclear Corporation (NNC) Sizewell B Plant Safety Analyses Pre-Operational Safety Report (POSR) Issued to Nuclear Installations inspectorate (Nil) November 1992 POSR Chapter 15 Section 5 (Code Section - LOFTS) has received Nll approval (June 10,1993)
Issue 1 of LOFT 5 Validation Source Submitted June 1992 Issue 2 of LOFT 5 Validation Source Submitted March 1993 "No Comments" on issue 2 Represents Nil Acceptance of LOFT 5 for Safety Analysis Applications Westinghouse Plans to Submit LOFT 5 to NRC in Late 1994.
WOG NRC Meeting 7/9/93:22
SAFETY ANALYSIS Westinghouse works with NNC to perform LOFT 5 analyses Perform bounding generic analyses of postulated asymmetric RCCA withdrawal events for a representative core design to demonstrate that DNBR limit is met Westinghouse will provide a final report by July 30,1993 describing the analyses and results to WOG licensees by July 30 I
WOG-NRC Meeting 7/9/93:23 i
s J
SAFETY ANALYSIS ANALYSIS PROGRAM OVERVIEW.
i e
Benchmark Current Bank Withdrawal Events for Representative W Plant P
e Analyze Current Bank Withdrawal Events with 3-D Methods (LOFTS)
Benefits due to Flux Flattening, Reactivity Feedback, etc.
Analyze Asymmetric Rod Withdrawal Events with 3-D Methods (LOFTS)
Assess penalty compared to 3-D Benefits Methodology Approach Applicable to all Westinghouse Plants Perform Sensitivities to Demonstrate Bounding / Limiting Peaking Factors for Asymmetric Withdrawals WOG-NRC Meeting 7/9/93:24
..c SAFETY ANALYSIS ANALYSIS PROGRAM OVERVIEW e
Demonstrate 3-D Method Benefit Exceeds Asymmetric Penalty e
Results Applicable Generically Confirms Limiting Scenarios Accurately / Conservatively Defines DNB Margin WOG.NRC Meeting 7/9/93:25
SCHEDULE June 2' Generic Letter 93-04 issued to licensees July 7:
Program authorizations approved July 9:
NRC meeting in Rockville, Maryland-July 15: RCS survey response due to Westinghouse July 23: Draft RCS failure survey report issued j
s Draft generic response to Generic Letter 93-004 issued Draft accident analysis report issued July 27: Start of actual testing (Day 21)
July 30: Final RCS failure survey report issued Final accident analysis report issued Final generic response to Generic Letter 93-004 issued Final failure assessment report issued Aug 5:
Original due date to NRC Aug 20: Proposed extended NRC due date (pending NRC approval)
Aug 25: Completion of testing (Day 50)
Sept 9:
Draft test report issued (Day 65)
Sept 24: Final test report issued (Day 80)
WOG-NR:: Meeting 7/9/93:26 i
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LONG-TERM CONSIDERATIONS Long-term actions to be considered based on:
Results of Rod Control Test Plan Results of Equipment Survey e
Maintenance Recommendations (Technical Bulletin) e Potential Design Enhancement (Hardware Fix)
Safety Analysis Results
)
WOG-NRC Meeting 7/9/93:27
DISCUSSION ITEMS Interpretation of GDC 25 (or equivalent) 45 day response to GL 93-04 NRC Feedback CLOSING REMARKS l
l l
WOG.NRC Meeting 7/9/93:28 s-w w
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