ML19320C427
| ML19320C427 | |
| Person / Time | |
|---|---|
| Issue date: | 06/23/1980 |
| From: | Phillips L Office of Nuclear Reactor Regulation |
| To: | Rubenstein L Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML19320C422 | List: |
| References | |
| RTR-REGGD-04.016, RTR-REGGD-4.016 NUDOCS 8007160814 | |
| Download: ML19320C427 (31) | |
Text
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NUCLEAR REGULATORY COMMISSION
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WASHINGTON, D. C. 20555 1,[ '.',(/
JUN 2 31000 MEMORANDUM FOR:
L. S. Rubenstein, Assistant Director for Core and Containment Systems Division of Systems Integration THRU:
R. O. Meyer, Acting Chief Core Perfomance Branch Division of Systems Integration FROM:
L. E. Phillips, Section Leader, Thermal Hydraulics Section, Core Perfomance Branch, DSI
SUBJECT:
SUMMARY
OF NRC/CE CWNERS GROUP MEETING ON INADEQUATE CORE C0 CLING (ICC)
A meeting was held at NRC in Bethesda, Maryland, on May 28, 1980, to review the ICC program. The agenda of the meeting and a list of meeting attendees is attached. The general purpose of the meeting was to review the current status and schedule for the CE Owners Group response to lessons Learned Inadequate Core Cooling requirements.
The owners were informed that pursuant to the NRR reorganization, the ICC review would be managed by the Themal ifydraulics Section of Cnre Perfomance Branch (CPB), NRC. The review responsibilities of other branches relevant to the ICC program were described.
CE presented a sumary of CEN-ll7 conclusions and further studies including causes of ICC, ground rules and the scope of ICC study, etc. CE also pre-sented a discussion of the Reactor Vessel Level Mcnitoring System (RVLMS) of CEN-ll5, including the objective, design basis, functional requirements, and design criteria. Copies of slides from the presentations are attached.
Gary Holahan of NRC presented the preliminary conclusions from his review of "CE Post-TMI Evaluation, Task 2, Conceptual Design for a Reactor Vessel Level Monitoring System," as follows:
1.
The system sensitivity to changes in the coolant condition needs to be addraised; and the expected response to Small Break and Large Break LOCA's needs to be evaluated by CE.
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L. S. Rubenstein JUN 2 31950 2.
The range of the instrumentation is described as, "from the top of the reactor vessel head to the bottom of the reactor vessel outlet nozzle."
This range is not adequate. We prefer a range extendina down to the bottom of the core, but recognize that this is beyond the prasent state-of-the-art for heated junction thennoccuples.
However, the range must be extended down to the elevation of the upper core aligivnent plate.
(This change has already been implemented.)
3.
The core exit thermocouples are needed to complement the heated thermo-couples and should therefore be qualified for use during post accident conditions.
4.
The proposed display (continuous monitoring and recording of the signal j
from each level sensor) is not sufficienc.
5.
The core exit thermocouples and the level sensors should be integratec into an easy-to-interpret display.
6.
We strongly encourage the development of a standard display and standard
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terminology to be used for instrumentation to detect inadequate core l
cooling.
7.
Procedures and training in the use of this system are required.
i George Liebler, Chairman of CE Owners Group -- ICC, presented a schedule for completion of the program as follows:
Task 1 (Syst>m functional design) by November 30, 1980; Task 2 (hardesre design) by December 31, 1980; Task 3 (Pratt:ype testing) by March 31, 1981; Task 4 (System qualifica. tion) by November 30, 1981.
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A copy of the schedule is attached. There was general recognition of the fact that the schedule does not satisfy the January 1981 implementation requirements of the Lessons Learned Task Force.
L. Rubenstein agreed to consider whether a letter :heuld be issued to reflect the staff position on the CE proposal approach.
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L. E. Phillips Section Leader Thennal Hydraulics Section Core Perfonnance Branch, DSI Attachments:
As stated cc:
G. Liebler, Florida Power & Light Company (10 cys. for Owners Group Attendees)
ATTENDEES NRC/CE Owners Group Meeting May 28, 1980 Name Orcanization Larry Phillips NRC - DSI/CPB Gary Holahan NRC - DST /SPEB L. Rubenstein NRC - DSI/CCS Jose Ibarra NRC -
Chang Li NRC - 00L/0RB-3 Monte Conner NRC - 00L/0RB-3 Bill Morris NRC - DSI/ICSB Tai Huang NRC - DSI/CPB Jack Guttmann NRC - DSI/RSB Rich Olson Balt. Gas & Elec.
Alan Thornton Balt. Gas & Elec.
Harry G. O'Brien Tenn. Valley Auth.
Joe Gasper Omaha Public Power Len Casella Florida Power & Light George Liebler Florida Power & Light Jim Osborne Florida Power & Light Bill Burchill C-E C. H. Neuschaefer C-E R. Bryan C-E J. M. Westhoven C-E C. Brinkman C-E (Bethesda)
R. Ivany C-E Lionel Bandz C-E Ralph Phelps So. Cal. Edison Co.
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MEETING AGENDA
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C-E OWNERS GROUP - INADEQUATE CORE COOLING I.
INTRODUCTION Gange g,,y pt,p,sc4 Lye
- Owners Group
- NRC II. REVIEW OF CEN-117 CONCLUSIONS AND FURTHER STUDIES h4 Igany, CE III. REVIEW OF CEN-125 AND FURTHER STUDIES Bob Bry a n CE.
IV. CONCLUSION
- Owners Group
- NRC 4
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a-i MEETING AGENDA i
C E OWNERS GROUP - INADECUATE CORE COOLING I.
INTKJOUCTION Genga hW pk. p 4 L. p
- Owners Group
- NRC II. REVIEW OF CEN-117 CONCLUSIONS AND FURTHER STUDIES Ag Iga y.
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III. REVIEW 0F CEN-125 AND FURTHER STUDIES 34 be
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- Owners Group
- NRC
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I INADEQUATE CORE COOLING OBJECTIVE:
RESPOND TO BULLETIN 79-06C, ITEM 5.
" PROVIDE ANALYSES AND DEVELOP GulDELINES AND PROCEDURES' RELATED T0 CORE COOLING (AS DISCUSSED IN SECTION 2.1.9 0F NUREG-0578,---) AND-- ".
SHORT TERM RESPONSE ONLY, PROVIDE A " STUDY OF INSTRUMENT RESPONSE G0ING INTO AND OUT OF INADEQUATE CORE' COOLING".
LONGER TERM RESPONSE TO NUREG-0578:
REQUIRES EXTENSIVE SURVEY OF TRANSIENTS AND ACCIDENTS, WITH SUBSEQUENT REVISIONS TO GUIDELINES AND EflERGENCY PROCEDURES.
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i POSSIBLE CAUSES OF INADEQUATE CORE COOLING CORE DNBR - FLOW BLOCKAGE
- POWER DISTRIBUTION ANOMALY LOSS OF COOLANT INVENT 0RY', LOCA LOSS OF HEAT SINK - LOSS OF FEEDWATER LOW POWER / SHUTDOWN EVENTS 9
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PRESSURE DNBR = FUNCTION OFW POWER
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FLOW RATE POWER DISTRIBUTION
' ANO COLSS POWER OPERATING LIMIT INDICATION TO OPERATOR <
PRE-ANO THERMAL MARGIN LOW PRESSURE TRIP PRESSURE & PRE-TRIP ALARM ADE00 ATE INDICATION TO NORMALLY TRAINED OPERATOR FOR EVENTS WHICH ARE SLOW EN0 UGH FOR HIM TO ACT ASSUMES NO CORE ANOMALY EXISTS I
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CPC CORE POWER DISTRIBUTION VARIABLE OVERPOWER HIGH LOCAL POWER DENSITY
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TM/LP IN-CORE FLUX / TEMPERATURE HIGH LOCAL POWER DENSITY i'
C01.SS CORE POWER DISTRIBUTION AZIMUTHAL TILT KW/FT MARGIN DNB MARGIN
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GROUNDRUIFS I
SELECT EVENTS WHICH HAVE A POTENTIAL FOR DEGRADING INTO INADECUATE CORE COOLING IF NO ACTION IS TAKEN USEAPPROACHTOCOREUNCdVERY, DISCUSSED IN CEN-H4. AS ANALYTICAL MEASUPI 0F CORE COOLING ADEQUACY j
BEST ESTIMATE ANALYTICAL METHODS ARE 3
UTILIZED PER NUREG-0578 C-E 2560 MWT CLASS OF REACTORS AS IN CEN-H4 AND CEN-H5 4
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. CORE COOLING WILL BE INADEQUATE 0NLY IF SIGNIFICANT CORE UNC0VERY EXIST.S FOR A SUBSTANTIAL PERIOD 0F TIME s
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= CORE UNC0VERY CAN ONLY OCCUR AS THE RESULT OF A NET LOSS OF >70% OF THE INITIAL RCS INVENTORY
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SELECT EVENTS WHICH HAVE A POTENTIAL FOR DEGRADING INTO INADECUATE CORE COOLING IF NO ACTION IS TAKEN USE APPROACH TO CORE UNC0VERY, DISCUSSED IN CEN-U4, AS ANALYTICAL MFASUFI 0F CORE COOLING ADEQUACY j
BEST ESTIMATE ANALYTICAL METHODS ARE UTILIZED PER NUREG-0578 C-E 2560 MWT CLASS OF REACTORS AS IN CEN-D 4 AND CEN-E 5 9
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CONTAINMENT ENVIRONMENT, LOSS OF NATURAL CONVECTION., RCPs 0FF
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- 6) FEEDWATER LINE BREAK, RESULTS IN ADVERSE CONTAINMENT ENVIRONMENT, LOSS OF NATURAL CONVECTION, RCPs 0FF
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CONCLUSIONSdFCEN-19 1.
REQUIRE LARGE AN0MALY TO REACH DNB.
CORE NON-SYMMETRY PROBABLY OBSERVABLE.
2.
PUMP MOTOR CURRENT IS GOOD MEASURE OF APPROAClllNG CORE UNC0VERY.
3.
INSTRUMENTS'5H0W WilETilER ESSENTIAL SAFETY EQUIPMENT IS FUNCTIONING.
11.
ANALYSES Sil0W ACCEPTABLE CONSEQUENCES IF OPERATOR AND EQUIPMENT FUNCTION l
AS PRESCRIBED IN GUIDELINES.
5.
W;Til PUMPS OFF, NO DIRECT -AND CONVENIENT INSTRUMENT TO Sil0W APPROACHING CORE UNC0VERY.
6.
AFTER CORE UNC0 vel 1Y, ll0T LEG RTD ANU Col (E EXIT. THERM 0 COUPLES CAN Sil0W
.{.-SUPERilEATANDAPPROACHINGINADEQUATECORECOOLING.
EXTENSION OF RANGE i
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d Oli)ECTIVE OF CONTUING STUDY DERIVE ThE TliERMAL AND HYDRAULIC FUNCTIONAL REQUIREMENTS FOR INSTRUMEiiTS TO NEASURE ICC FORhulATE A RECOHHENDATlud ON THE NEED FOR NEW INSTRUMENTATION i
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SCOPE OF ICC STUDY 1.
ESTAlillSil CRITERIA FOR INADEQUATE CORE COOLING BASED ON FUEL CLAD PERFORMANCE 2.
PROVIDE TiiERML AND tlYORAULIC FUliCTIONAL REQUIREMENTS ON EXISTING AND HLW INSTRUMENTS FOR A SET OF EVENTS ANALYiED 3.
OBTAIN DETAILED RESPONSE OF EXISTlHG lilSTRUNEilTS A.
RID TiiERhAL ANALYSIS i
B.
SPHD TilERNAL AllALYSIS C.
CORE EXIT TilERM0 COUPLE TiiERML RESPONSE D.
EX-CORE NEUTRON DLTECTOR RESPONSE TO UNC0VERY 4.
EVALUATE INSTRUNENT INDICATIONS AS A MEANS OF DETECTING ICC j
A.
SullC00 LED MARGIN MONITUR b.
REACTOR VLSSEL LEVEL MONITOR C.
NATURAL CIRCULATION LOW FLOW HONITOR FORHULATE CONCLUSION ON NEEb FOR llEW IllSTRbtlENTS, 12/31/80 1
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REACTOR VESSEL LEVEL MONITORING SYSTEM (RVU4S)
CONCEPTUAL DESIGN TASK
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i' OBJECTIVE OF RVLMS CONCEPTUAL DESIGN TASK RESPOND TO NRC REQUIREENT TO DEVELOP SYSTEM CONCEPTUAL DESIGN AND FUNCTIONAL REQUIREENTS (NUREG 0578, ITEM 2.1.3,s).
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RVLMS DESIGN BASIS INFORM THE PLANT OPERATOR THAT THE REACTOR VESSEL INVENTORY IS AFFECTED, SPECIFICALLY, BY AN EVENT.
e SENSE REACTOR VESSEL LEVEL CONTINUALLY RECORD e
PROVIDE ALARM AND ANNUNCIATION e
POST ACCIDENT MONITORING SYSTEM O
FUNCTIONAL REQUIREMENTS t
e REGULATORY GUIDE 1.97 POST ACCIDENT MON'TORING SYSTEM 1
e SENSOR MEASURES FLUID IN REACTOR VESSEL e
RANGE FROM TOP OF HEAD TO TOP 0F CORE e
DISPLAY REACTOR VESSEL LEVEL IN THE CONTROL ROOM e
ALARM TO ALERT THE OPERATOR e
QUALIFIED SEISMICALLY AND ENVIRONMENTALLY e
UNIQUE INDICATION OF SYSTEM MALFUNCTION l
RVLMS DESIGN CRITERIA DIRECT MEASUREMENT NON-HYDRAULIC NO MOVING PARTS REDUNDANT NO CHANGES TO EXISTING REFUELING PROCEDURES MINIMUM IMPACT ON EXISTING NSSS DESIGN NO IN-CONTAINMENT ELECTRONICS REPLACE SENSOR WITHOUT REMOVING THE R. V. HEAD
SENSOR NO NO MINIMUM NO IN-REPLACEMENT DIRECT NON-MOVING REFUELING IMPACT ON CONTAINMENT W/0 HEAD MEASilRF HYDRAtlt IC PARTS RRullmANT CHANGES NSSS DESIGN ElFCTRONICS REMOVAL o
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