ML16245A663
| ML16245A663 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse, Oconee, Arkansas Nuclear, Crystal River, Rancho Seco, Crane  |
| Issue date: | 11/10/1981 |
| From: | Vissing, Vissing H Office of Nuclear Reactor Regulation |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| TASK-2.K.3.30, TASK-TM TAC-45859, NUDOCS 8112040303 | |
| Download: ML16245A663 (19) | |
Text
Nov,,
Dockets Nos. 50-313, 50-302, 50-346, 50-269/270/287, 50-312 and 50 LICENSEES: Babcock & Wilcox Owners Group (B&W) ( G)
SUBJECT:
SUMMARY
OF THE MEETING WITH EXECUTIVE REPRESENTATIVES OF THE OWNERS OF B&W OPERATING PLANTS CONCERNING EXPERIMENTAL VERI FICATION OF ACCIDENT MODELS ON OCTOBER 23, 1981 Introduction The meeting was held in Bethesda, Maryland at the request of the B&W OG in order to:
(1) respond to the staff's concerns regarding.the behavior of B&W designed NSSSs during recovery from small break loss of coolant accidents (SBLOCAs) and (2) topermtt the executive.management levels of the B&W operating plants owners to express a commitment to resolve these staff concerns. provides a list of attendees to the meeting. provides the slides whi ch were used to present the staff's concerns. Enclosure 3 illustrates the SBLOCA OG Pro ram.
Discussion The staff discussed the concerns related to the behavior of the B&W reactors cod1ant s~stem (RCS) during therecovery from certain SBLOAs and the con cerns related to high point vents in t1he RES and vessel water level instru mentation.
The B&W Owners believe that the B&W SBLOCA Program and the Abnormal Transient Operating Guidelines (ATOG)
Pro ram will provide confidence in the behavior of the B&W system.
The 8&W Owners exprqssed a desire to work in parallel with the staff to resolve the concerns of the dynamics of the RCS and the ATOG Program.
The B&W Owners proposed a program to resolve the concerns through a joint effort with the staff, the'B&W OGand B3&W within one month of completion of the B&W SBLOCA Program or June 1, 1982, whichever is earlier. The program would consist of: (1) an understanding of the programs underway, (2) a review of the codes, models, assumptions and the avail ble experimental data related to the dynamics of interest, (3) defining needed additional experimental data which addresses specific technical gaps and (4) identifying.Ihere and how addi tional experimental data may be obtained.
The staff agreed that this program is.acceptable.with the conditin that the licensee commit.at this.time to the implementation of high point vents in the RCS and vessel water level instru mentation.
8112040303 8111101 PDR ADOCK 05000269 P
fDR
-2 The staff requested information regarding results of the testing which B&W is doing for the Germans regardilng their B8R experience.
ColtI us ions The B&W Owners committed to provide in writi ng:
(1) their proposed program for resolving the issue, and their respons -regarding the implementation of high point vents in the RCS and water level ins r mentaton B&W will identify what information regarding the testing binq done for the Germans will be' provided to the staff.
Guy S. Vissing, Project Manager Operating Reactors Branch #4 Division of Licensing Enclosures;
- 1. List of Attendees
- 2.
NRC Staff Concerns
See next page OFFICE)
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DATE NRC FORM 318 (10-80) NRCM 0240 FFICIAL RECORD COPY USGPO: 1981-335-960
MEETING
SUMMARY
DISTRIBUTION Licensee: AP&L, FPC, TECO, DPC, SMUD, MET ED (GPU NUCLEAR)
- Copies also sent to those people on service (cc) list for subject plant(s).
Docket File-8 NRC PDR-8 L PDR-8 ORB#4 Rdg TNovak JStolz Project Manager -G'Sf PErickson, DGarner, PWagner, Licensing Ass stant -2 iPadovan, HSilver, RJacobs 0ELD Heltemes, AEOD IE-3 SShowe (PWR),.,JE Meeting Summary File-ORB#4 RFraley, ACRS-10 Program Support Branch J01shinski
- SRamos, EPDB
- FPagano, EPLB BSheron JKramer J14azetis N[Lauben WLyon DZiemann HDenton RMattson TMurley ATTENDANCE LIST TO MEETING WITH OWNERS OF OPERATING B&W NSSS CONCERNING EXPERIMENTAL VERIFICATION OF ACCIDENT MODELS OCTOBER 23, 1981 NRO TECO Brian W. Sheron Richard P. Crouse Guy S. Vissing John Stolz Joel Kramer Darrell Eisenhut GPU NUCLEAR Jerry Mazetis Norman Lauben R. F. Wilson Warren Lyon Lov Lanese Dennis Ziemann Bob Keaton Harold Denton Roger Mattson T. Murley SMUD John Mattimoe B&W Don H. Roy John Bohart AP&L John M. Griffin FPC John A. Hancock CONSUMERS PWR. CO.
Roy Wells WASH. PUBLIC PWR.
Don Bouebey DUKE PWR. CO.
William 0. Parker, Jr.
TVA John Raulston VEPCO Jim Carter James East
NRC STAFF CONCERNS REGARDING BEHAVIOR OF B&W-DESIGNED NSSSs DURING TRANSIENTS AND ACCIDENTS 40 0'1 (D
BACKGROUND
-FOLLOWING TMI-2, VENDORS REQUESTED TO EXAMINE AREAS OF SMALL BREAK SPECTRUM NOT NORMALLY ANALYZED FOR FSAR
-IN RESPONSE TO MICHAELSON CONCERN, B&W REEXAMINED HOT LEG NODALIZATION. WHEN DUAL FLOW PATH USED, CERTAIN SMALL BREAKS PREDICTED TO TRAP STEAM AT TOP OF HOT LEG
-BREAK IN CIRCULATION PATH PRODUCED TEMPORARY LOSS OF HEAT SINK: SYSTEM REPRESSURIZED TO
(
NEAR PORV SETPOINT
-RAISED LOOP PLANTS PREDICTED TO HAVE 3 REPRESSURIZATION/DEPRESSURIZATION CYCLES
-B&O TASK FORCE JUSTIFIED CONTINUED OPERATION OF B&W PLANTS BASED ON EXPECTED EXPOSURE OF CONDENSING SURFACE PRIOR TO CORE UNCOVERY
-PHENOMENON WAS UNEXPECTED AND ANALYSES HIGHLY UNCERTAIN. STAFF EXPECTED THAT FURTHER WORK, PRIMARILY EXPERIMENTAL, WOULD HAVE TO BE PERFORMED.
CONCERNS
-STEAM TRAPPING PHENOMENON IS UNCERTAIN: WILL IT REALLY OCCUR OR WILL FROTHING IN HOT LEG MAINTAIN CONTINUOUS CIRCULATION?
-HOW CAN THE STAFF BE ASSURED THAT NO NEW, UNDISCOVERED PHENOMENA UNIQUE TO B&W PLANTS EXIST?
-HYDRAULIC STABILITY DURING LONG-TERM COOLING
-NEED FOR VENTS/RCPs TO ESTABLISH LONG-TERM COOLING
-BREAK ISOLATION
-NC INTERRUPTION/PREPRESSURIZE TO PORV SETPOINT?
-OPERATOR MAY BE CONFUSED BY ACTUAL PLANT BEHAVIOR AND TAKE INCORRECT ACTIONS BASED ON UNEXPECTED SYMPTOMS
-WHILE IT IS HOPED PRESENT ATOG PROGRAM WILL PREVENT INCORRECT OPERATOR ACTIONS, PROCEDURES CANNOT SUBSTITUTE FOR A SOUND KNOWLEDGE OF THE DYNAMIC BEHAVIOR OF THE PLANT
-THE STAFF BELIEVES THAT ADDITIONAL EXPERIMENTAL DATA IS REQUIRED TO PROPERLY VERIFY THE THERMAL-HYDRAULIC PHENOMENA UNIQUE TO B&W REACTORS DURING TRANSIENTS AND ACCIDENTS
-AN IMPORTANT PART OF THE BASIS FOR CONTINUED OPERATION OF B&W PLANTS FOLLOWING TMI-2 WAS THAT CONFIRMATORY EXPERIMENTAL DATA WOULD BE PROVIDED AT A LATER TIME
-AT PRESENT, THE STAFF DOES NOT HAVE THE SAME DEGREE OF CONFIDENCE IN THE ABILITY TO PREDICT SMALL BREAK AND TRANSIENT BEHAVIOR IN B&W REACTORS AS WE DO FOR OTHER DESIGNS
-NODALIZATION STUDIES (PREVIOUSLY PROPOSED) ARE HELPFUL BUT CANNOT CONFIRM ABILITY OF MODEL TO PREDICT BEHAVIOR BECAUSE ACTUAL BEHAVIOR WILL REMAIN UNKNOWN WITHOUT TESTING
-STAFF CONCERNS REGARDING UNCERTAINTY OF B&W REACTOR BEHAVIOR INCLUDE BOTH THE CONSERVATIVE MODELLING REQUIRED FOR APPENDIX K CONFORMITY AND THE REALISTIC MODELLING REQUIRED FOR OPERATOR GUIDELINES
-WITHOUT SOME DATA, THE B&W PLANT OWNERS MAY NOT BE ABLE TO DEMONSTRATE THAT THE B&W SMALL BREAK EVALUATION MODEL IS IN CONFORMANCE WITH APPENDIX K TO 10CFR50 OR THAT CHANGES IN THE MODEL TO IMPROVE ITS REALISM ARE SUFFICIENT TO MEET THE REQUIREMENTS OF TMI ACTION PLAN ITEM II.K,3.30
FIGURE
.L 3
CO RE PRESSURE VS. TIME 0.01 FTZ BREAK AT PUMP DISCHARGE-SYMflETRIC ANW 0
A 20.000 II r, TIL lSP TI
HEIGHT HOT LEG LEVEL (FT) o = Broken Loop (Node 4)
NATURAL CIRCULATION LOST x
- Unbroken Loop (Node 14) 45 40 Node 14 35 Node 4 30 25 20 15 10 50 0
-J 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000 TIME (SECONDS)
FIGURE (.2-/S/
CORE PRESSURE VS.
TIME RAISED-LOOP SMALL BREAK 2 13. 0)
- 22.
X.x 1.5.3x 14 0X' C0.
6..11 0
La
- cI o
00:
sc:
- 20.cco 25.0, TMEX I \\LU L.. L_
FIGURE
- 6. 2-/.J3 PRESSURIZER LEVEL VS. TIME RAISED-LOOP SMALL BREAK L6.
Lu~
5-J 06
-JT z
Lic.'~
FIGURE. C. 2 - Sf HOT LEG MIXTURE LEVEL IN BROKEN LOOP VS.
TIME 5
RAISED LOOP SMALL BREAK C.D 01 T TI.E CSECX r
\\t.
- jc-6 N4i.
FIGURE C 2 /IS"'
-C INTACT LOOP HOT LEG MIXTURE LEVEL VS.
TIME -
RAISED LOOP SMALL BREAK C :tQ 8 500 sac xle Mk4
.J 11 0.ee:-
- ac~co as~ c:.
0.-::--.---.--
~~FIGURE
~Z/*
HOT LEG TEMPERATURE IN BROKEN LOOP VS. TIME
~
RAISED LOOP SMALL BREAK s=
C 55O w ~
T~I 1%
FIGUREC 2 S7
-zo COLD LEG TEMPERATURE IN BROKEN LOOP VS. TIME RAISED LOOP SMALL BREAK SC.000 S55.004" I
~55
.0 55.00; I.0"
~C3D
.O72 =0 NE:
~
,_Z; ;uI-'
C-MOMA rtvt VPPBL BeoAe&XJ LOOP VS i OLe
- ISO 64 90 0.
II SBLOCA OW ERS MINP PROGRAM
- P80GMM FORMULATED BETWEEN 9/80 WOO/8 e
REVIEW WITH THE STAFF 12/16/80
- STARTED WORK 2/81 TASKi I 1"L REVE &PRDE Leak Discharge Model Surge Line Model NUREG 0630 SMixture Level and Heat Transfer TASK 2 ISME DELOPMENT AND IMPLEMETATION Stem. Generator Node]
Pressurizer Model Two-phase Pump Model Two-phase Flow Model
-Heat Transfer with Non-Candnsbles TASK 3 PLANT SECIFIC ANALYSIS Complete 611182)
-AuxiI ary Ftewater Model Nolding Sensitivity Studies' l-Topical Report