ML20147A550
| ML20147A550 | |
| Person / Time | |
|---|---|
| Site: | Duane Arnold  |
| Issue date: | 05/26/2020 |
| From: | Christopher Hunter NRC/RES/DRA/PRB |
| To: | |
| Littlejohn J (301) 415-0428 | |
| References | |
| LER 1989-003-00 | |
| Download: ML20147A550 (5) | |
Text
B-183 ACCIDENT SEQUENCE PRECURSOR PROGRAM EVENT ANALYSIS LER No:
Event
Description:
Date:
Plant:
331/89-003 Reactor scram and isolation with RCIC out of service March 4, 1989 Duane Arnold Summary A special procedure involving the injection of hydrogen into feedwater lines for stress corrosion cracking control led to a spurious main steam line high radiation scram and reactor isolation. The reactor core isolation cooling (RCIC) system was unavailable at the time of the scram. The core damage probability estimated for the event is 6.5 x 10-6.
The relative significance of the event compared with other potential events at Duane Arnold is shown below.
LER 331/89-003 IE-7 1E-6 1E-5 1E-4 1E-3 1E-2
+ RCIC HPCJ Lprecursor cutoff Event Description The plant was at 100% power when a special test procedure related to in-reactor stress corrosion cracking was undertaken. The procedure required the injection of hydrogen into the feedwater system to determine the point at which stress corrosion cracking would be eliminated. An incorrectly sized flow orifice was used, and excessive amounts of hydrogen were injected. This resulted in an increase in steam line radiation levels sufficient to cause a unit scram and group 1 isolation. RCIC received a vessel low-low level initiation signal but was out of service (reason unspecified) and could not initiate.
B-184 ASP Modeling Assumptions and Approach The event has been modeled as a scram and isolation with RCIC unavailable.
Analysis Results The conditional probability of severe core damage estimated for this event is 6.5 x 10-6.
The dominant sequence to core damage involves successful high-pressure core cooling with failure to remove heat from the suppression pool in the long term. The dominant core sequence for this event is highlighted on the following event tree.
B-185
__ I RI I
I _,H:PCI
=LC I
4RSW IETR S 1
S S
RUT C
S LCI (SOC ICOOtINGI B DT"IPIsHADS (RHR) M ODE) M ~ODhE).
SEO BND No STATE li 12 OK OK O1<
CORE DAMAGE 01<
CORE DAMAGE
.11 CORE DAMAGE OK 09<
CORE DAMAGE Ox OK CORE DAMAGE Ox OK CORE DMG OK CORE DAMAGE OK CORE DAMAGE CORE DAMAGE CORE DAMAGE DOK CORE DAMAGE OK OK CORE DAMAGE OK OK CORE DAMAGE ox CORE DAMAGE OK CORE DAMAGE 01< DAAG CORE DAMAGE CORE DAMAGE OK OK CORE DAMAGE OK OE CORE DAMAGE OK 0 K CoRE DAMAGE CORE DAMAGE OK GE CORE DAMAGE OK CORE DAMAGE OK CORE DAMAGE COREDMG CORE DAMAGE ATWS Dominant core damage sequence for LER 331/89-003
B-186 CONDITIONAL CORE DAMAGE PROBABILITY CALCULATIONS Event Identifier:
331/89-003 Event
Description:
Reactor scram and isolation with RCIC unavailable Event Date:
03/04/89 Plant:
Duane Arnold INITIATING EVENT NON-RECOVERABLE INITIATING EVENT PROBABILITIES TRANS SEQUENCE CONDITIONAL PROBABILITY SUMS End State/Initiator
- 3. OE-05 TRANS Total SEQUENCE CONDITIONAL PROBABILITIES (PROBABILITY ORDER)
Sequence 11 trans -rx.shutdown PCS/TRANS srv.chall/trans.-scram -srv.close
-fw/pcs.trans rhr(sdc) rhr(spcool) /rhr~sdc) 28 trans -rx.shutdown PCS/TRANS srv.chall/trans.-scram srv.close fw/pcs.trans hpci srv.ads 12 trans -rx.shutdown PCS/TRANS srv.chall/trans.-scram -srv.close fw/pcs.trans -hpci rhr(sdc) rhr(spcool)/rhr(sdc) 20 trans -rx.shutdown PCS/TRANS srv.chall/trans.-scram -srv.close fw/pcs.trans hpci RCIC crd srv.ads 99 trans rx.shutdown non-recovery credit for edited case SEQUENCE CONDITIONAL PROBABILITIES (SEQUENCE ORDER)
Sequence 11 trans -rx.shutdown PCS/TRANS srv.chall/trans.-scram -srv.close
-fw/pcs.trans rhr(sdc) rhr(spcool)/rhr(sdc) 12 trans -rx.shutdown PCS/TRANS srv.chall/trans.-scram -srv.close fw/pcs.trans -hpci rhr(sdc) rhr(spcool) /rhr(sdc) 20 trans -rx.shutdown PCS/TRANS srv.chall/trans.-scram -srv.close fw/pcs.trans hpci RCIC crd srv.ads 28 trans -rx.shutdown PCS/TRANS srv.chall/trans.-scram srv.close fw/pcs.trans hpci srv.ads 99 trans rx.shutdown non-recovery credit for edited case SEQUENCE MODEL:
c:\\asp\\1989\\bwrcseal.cmp BRANCN MODEL:
c:\\asp\\1989\\duarnold.sll PROBABILITY FILE:
c:\\asp\\1999\\bwr csll.pro No Recovery Limit BRANCH FREQUENCIES/PROBABILITIES Branch System Non-Recov End State CD CO CO CD Prob 4. 8E-06
- 6. 7E-07 5.2E-07
- 3. 4E-07 N Rec**
1.1E-01 1.7E-01
- 4. 8E-06 5.2E-07 3.4E-07
- 6. 7E-07
- 3. OE-05 N Rec**
- 1. lE-Ol 3.9E-02
- 1. 2E-01 1.7E-01 1.OE+00 Opr Fail Event Identifier: 331/89-003
B-187 trans loop loca rx. shutdown rx.shutdown/ep P CS/TRANS Branch Model:
l.OF.1 Train 1 Cond Prob:
srv.chall/trans.-scram srv. chall/loop.-scram srv. close emerg.power ep. rec fwlpcs.trans fw/pcs.loca hpci RCIC Branch Model:
l.OF.1 Train 1 Cond Prob:
crd a rv.ads lpcs lpci (rhr) /lpcs rhr (sdc) rhr(sdc) /-lpci rhr(sdc) /lpci rhr(spcool) /rhr(sdc) rhr (spco~ol) /-lpci.rhr (sdc) rhr(spcool) /lpci.rhr (sdc) rhrsw 8.2E-05
- 1. 6E-05
- 3. 3E-O 6
- 3. OE-05
- 3. 5E-04 1.7E-01
> l.OE+00 1.7E-01 > Unavailable l.OE+00 l.OE+00 2.6E-02 2.9E-03
- 6. 6E-02
- 2. 9E-01
- 4. OE-.02
- 2. 9E-02 6.OE-02 > l.OE+00 6.OE-02 > Unavailable 1.0 E-02
- 3. 7E-03 3.OE-03 1.OE-03 2.1lE-02 2.OE-02 l.OE+00
- 2. OE-03
- 2. OE-03
- 9. 3E-02 2.OE-02
- 1. OE+00
- 3. 6E-01 5.0 E-01 l.OE+00
- 1. OE+00 l.OE+00
- 1. OE+00
- 1. OE+00
- 1. OE+00
- 8. OE-0l 1.OE+00 3.4E-01 3.4E-01
- 7. OE-01
- 7. OE-01
- 1. OE+00 7. IE-01 3.4E-01
- 7. 1E-01 3.4E-01
- 3. E-01
- 1. OE+00 3.4E-01 3.4E-01 l.OE+00 3.4E-01
- 1. OE-02 1.OE-02 1.OE-03 l.OE-03 l.OE-03 2.OE-03
- branch model file Sforced Minarick 06-12-1990 08:41:56 Event Identifier: 331/89-003