ML20237B990
| ML20237B990 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 07/03/1997 |
| From: | Palla R NRC (Affiliation Not Assigned) |
| To: | Holahan G NRC (Affiliation Not Assigned) |
| References | |
| FACA, NUDOCS 9808200142 | |
| Download: ML20237B990 (40) | |
Text
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, pRfffy y a UNITED STATES g ,3 NUCLEAR REGULATORY COMMISSION p, f WASHINGTON. D.C. 20566 4 001 k*****,o July 3, 1997 MEMORANDUM T0: Gary M. Holahan. Director Division of Systems Safety and Analysis Office of Nuclear Reactor Regulation THRU: Carl H. Berlinger. Chief Containment Systems and Severe Accident Bra N '
i Office of Nuclear Reactor Regulation J\
FROM: Robert L. Palla. Sr. Reactor Engineer "
Containment Systems and Severe Accident Branch Office of Nuclear Reactor Regulation
SUBJECT:
SEVERE ACCIDENT MANAGEMENT DEMONSTRATION VISIT AT COMANCHE PEAK. MAY 29-30. 1997 On May 29 and 30, 1997, an NRC team attended a severe accident management implementation " demonstration" at the Comanche Peak Steam Electric Station (CPSES) in Granbury. Texas. Team members included Carl Berlinger and Robert Palla. Containment Sistems and Severe Accident Branch James O'Brien.
Emergency Preparedness and Radiation Protection Branch. David Desaulniers.
Human Factors Assessment Branch, and Blaine Murray, Region IV.
The CPSES visit was the first of a series of industry-hosted demonstrations organized by the Nuclear Energy Institute (NEI). NEI has proposed these demonstrations as an alternative to staff pla'is for confirming the adequacy of licensee implementation of accident management (A/M). Staff plans outlined in SECY-96-088, include a sequence of information gathering visits, pilot inspections, and more focussed inspections at the remainder of plants.
Re^resentatives from NEI the Westinghouse Owners Group (WOG). and several otherlicenseesalsoattendedthedemonstration. A list of attendees is provided as Attachment 1 An agenda is included as Attachment 2.
The purpose of the demonstration was to arr vide the NRC and visiting utility representatives insights on Comanche Peat's impla.entation of severe accident 4 management pursuant to the formal industry i m tion contained in NEI 91-04 Revision 1. The staff's objectives for the visit were to gain insights into:
(1) the licensee's implementation / evaluation process, including development and implementation of plant-specific severe accident management guidelines (SAMG). training of personnel, real-time use of SAMG during drills, and licensee self-assessment of drill performance. (2) how well the draft Temporary Instruction (TI) on A/M implementation would guide the inspection j
effort, and where changes to the guidance may be needed, and (3) whether the industry-sponsored demonstrations may justify modification of the planned g inspection process. It was also recognized that the results of the first i demonstration would provide useful information in structuring subsequent 0\
demonstrations.
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ad l The visit started with a series of presentations overviewing the licensee's l A/M implementation effort. Specific presentations were made on: development and implementation of-)lant-specific SAMG. the training of personnel, the inclusion of IPE insigits, setpoint and computational aid development, and i
! instrument validation. Presentation materials are provided as Attachment 3.
The presentations were followed by an A/M drill, in which the SAMG were used by members of the licensee's emergency response organization.
The drill scenario was initiated by a loss of all feedwater in Unit 1.
followed by a loss of all power to emergency AC busses. Significant RCS leakage from a small LOCA was also specified. Actions to recover turbine-driven AFW were not taken (they would not be effective since the steam generators become decoupled due to the LOCA). Steps to cross-connect systems from Unit 2 were also not taken. Actions to recover diesel generators were initiated, but involved substantial delays. With feedwater and RCS makeu) unavailable, core uncovery and heatup occurred, resulting in entry into t1e SAMG. Core damage continued and fission products and hydrogen were released into containment via the breach in the RCS. Fission products were released to the environment via a small leak in the equipment hatch, but containment pressure remained elevated. Eventually, a diesel generator was recovered and power to ECCS and containment spray was subsequently restored. The drill was terminated at that time. Additional information regarding the scenario is provided as Attachment 4.
The drill involved full staffing and simulation of activities in the control room and technical support center, and the use of a control cell (single player / communicator) in the Emergency Offsite Facility (E0F) and the Operations Support Center (OSC). The first portion of the drill was simulator-driven and staged in the plant's simulator facility. Following drill initiation. E0P-directed actions, event classification, and transition from E0Ps to the SACRG-1 portion of the SAMG-(which addresses control room actions prior to activation of the Technical Support Center (TSC)) were simulated. Staffing and actuation of the TSC was simulated in )arallel.
Following TSC activation, branching to the SACRG-2 portion of tie SAMG (which addresses control room actions following activation of the TSC), and the transfer of responsibility to the TSC were simulated. At this point the drill was frozen, the drill observers moved from the simulator to the TSC, and the drill was then restarted. Actions simulated within the TSC included those functions normally carried out in the TSC (e.g., inter-facility coordination and communication, use of plant data to assess plant status, and providing guidance to the control room operating personnel), as well as use of the SAMG by two TSC engineers to evaluate potential strategies contained within the SAMG and develop recommendations on response actions and priorities. i A brief " exit" meeting was held on the second day during which the licensee described their drill findings (Attachment 5), and the NRC and NEI provided their respective observations. Major staff observations were discussed at the exit meeting and are provided below. The observations are based largely on information presented during the presentations, without the opportunity for staff follow-up. and should not be construed as conclusions:
Development and Implementation of SAMG e Information ]rovided during the presentations was useful, and generally indicative tlat each of the major elements of the formal industry position on severe accident management (Chapter 5 of NEI 91-04 Revision 1) have been addressed by the licensee. Additional discussion and review of severe accident materials and records would be needed to confirm this observation.
e Three areas where information provided was insufficient to resolve staff questions included: (1) the manner in which plant-specific IPE insights were incorporated into the licensee's emergency response ca) abilities (the licensee did not incorporate additional IPE insights into t1e plant- '
specific SAMG. or use a systematic process, such as NUMARC 92-01, for evaluating the capability to respond to important IPE sequences), (2) the availability of plant procedures and pre-staged equipment for implementing accident management strategies (no strategy implementing procedures were developed and no equipment was pre-staged as a result of SAMG implementation), and (3) the process used to assure that instrumentation relied upon in the plant-specific SAMG would be available during severe accidents, such as station blackout or sequences involving loss of DC bus Increased attention in these areas should be considered in any future demonstration.
e The plant-specific SAMG and training materials were not examined during the visit. Some familiarization with the plant-specific documents would be useful-in better understanding the implementation process, and should be I considered for future demonstrations.
e The licensee's presentation did not provide clear .1dication that the SAMG j training was implemented and will be effectively L.aintained using a systems approach to training. For example, no basis was provided for the training methods selected (i .e. , classroom and required readings). Given the amount of interaction and coordination required among personnel in the TSC, and between the TSC and the control room, it appeared that methods whica ;
provide more opportunity to exercise implementation skills would have been 1 appropriately considered in the training design. Similarly, the licensee's i program for evaluating and revising training did not. appear to support '
com]rehensive or timely assessment. Annual refresher training using wor (books will be the licensee's primary source of feedback for assessing training effectiveness. The use of workbooks can not be expected to provide adequate feedback concerning the ability to implement the SAMGs in real time. Although a table-top exercise is planned for every other year, only one crew is expected to participate, consequently the amount of feed-back regarding training effectiveness will be limited. On average, personnel in the TSC would experience the " training" benefit of this l activity once every 6 years, and control room staff would participate in a l
l SAMG table-top once every 10 years (assuming a five shift rotation). The table-top exercises were not considered a refresher training requirement.
e The licensee added a position to the TSC engineering team to support use of the SAMG, and modified their emergency plan implementing procedures (EPIPs) to address changes in the assignment of emergency organization i
__ _ _ _ _ _ - - _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ 1
4_
responsibilities associated with the SAMG. The licensee did not consider it necessary to modify its emergency plan to recognize SAMG because the plan is written at a higher level. The licensee indicated that changes to the plant emergency operating procedures (regarding the transition to SAMG) and the EPIPs were evaluated in accordance with plant practice concerning 10 CFR 50.59 and 50.54 (q). respectively.
e The licensee has adopted a philosophy that a single 50.54 (x) and (y) determination will be made upon entry into SAMG, rather than considering each action taken under SAMG individually with respect to 50.54(x) and (y).
The staff noted that this is inconsistent with staff views expressed during the March 11-13 NEI Severe Accident Management Implementation Workshop in Charlotte, and that a formal position on this matter will need to be de" eloped.
A/M Drill Performance and Self Assessment Process e In general, the SAMG appeared beneficial in increasing the technical support staff's awareness of the potential negative impacts of certain actions and in assisting in the prioritization of activities. Use of the SAMG resulted in deliberate consideration of potential impacts of strategy implementation that might not have been considered otherwise, such as the threat to steam generator tubes by restoration of feedwater, and the threat of hydrogen combustion from restoration of containment sprays. Computa-tional aides developed to provide information on the capability of injection sourcet and combustion limits also appeared useful.
e Improvement in licensee's emergency response is likely with SAMG implementation due to improved understanding of severe accidents and the availability and use of computational aides. However, use of SAMG can adversely affect emergency response if the guidelines are difficult to follow or personnel are not 3roficient in their usage. Based on drill observations, ev.ecution of tie SAGS appeared time consuming, and associated technical evaluations contributed to delays in developing recommendations on restarting systems (including ECCS) following recovery of diesels.
Additional, periodic evaluator training in a drill setting appears prudent in order to improve the proficiency in SAMG use. and timeliness of recommendations.
e In this drill, the SAMG did not lead to identification of response strategies beyond those which might normally be identified by the TSC staff. For example, two accident mitigation strategies pursued during the drill -- spraying the leaking hatch with firewater'and attempting to
~
connect diesel-driven fire pumps to the containment sprays -- were developed on the fly during the drill and did not derive from the SAMG.
The licensee indicated that injection of firewater into the containment spray header will be further evaluated for inclusion in SAG-4.
e The degree of participation and staffing of the various emergency response ,
facilities in the A/M drill appeared appropriate for demonstrating the i transition from E0Ps to SAMG. and command and control issues. Strategy i
5-implementation by recovery teams was not su. .. lated and could be useful for confirming the feasibility of implementing certain strategies in future drills.
e The licensee's self-assessment process resulted in identification of a number of areas for improvement, including drill control transfer /
communication / display of data between and within facilities. and minor modifications to the SAMG documents. However, the TSC critique appeared cursory, and did not include an assessment of Performance agcinst any type of performance-based criteria. In addition, t1e number of evaluators appeared limited, and an inter-facility critique (joint discussion between players or drill evaluators in the control room and TSC) was not performed.
The latter could be helpful in addressing command and control issues.
Viability of the Demcastration Process e The demonstration 3rovided a good overview of actions taken by the licensee to implement A/M.10 wever, the information provided (prior to and during the visit) as well as the length of the visit was too limited to permit the sijff to determine whether the licensee had met the commitment for implementing severe accident management. Transmittal of the drill scenario package well in advance of the drill and inclusion of additional information in the package (e.g. , background information on plant-specific A/M implementation, and drill scenario timeline and evaluation criteria) would improve the ability of the staff to provide meaningful feedback, and is recommended as a goal for future demonstrations. Additional time should also be allocated to permit follow-up on questions / concerns identified during the presentations or drill.
e The A/M demonstration visit met the established objectives of providing insights into the licensee's implementation / evaluation process, and areas where changes to the draft TI may be needed. Due to the limited nature of the demonstration, and the potential differences in implementation among utilities and NSSS designs, additional demonstrations will be needed in order to form a consolidated view on the industry implementation process, necessary changes to the TI and the need for any adjustments to the planned inspection process.
e Some level of NRC inspection of severe accident management implementation appears necessary at each plant to assure that its implementation meets the intent of the program, and does not decrease the effectiveness of emergency response.
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implementation by recovery teams was not simulated and could be useful for confirming the feasibility of implementing certain strategies in future drills.
e The licensee's self-assessment process resulted in identification of a number of areas for improvement, including drill control, transfer /
communication / display of data between and within facilities, and minor modifications to the SAMG documents. However, the TSC critique appeared cursory, and did not include an assessment of performance against any type of performance-based criteria. In addition, the number of evaluators appeared limited, and an inter-facility critique (joint discussion between players or drill evaluators in the control room and TSC) was not performed.
The latter could be helpful in addressing command and control issues.
Viability of the Demonstration Process e The demonstration 3rovided a good overview of actions taken by the licensee to implement A/M.10 wever, the information provided (prior to and during the visit) as well as the length of the visit was too limited to permit the staff to determine whether the licensee had met the commitment for implementing severe accident management. Transmittal of the drill scenario i package well in advance of the drill and inclusion of additional {
information in the package (e.g., background information on plant-specific l A/H implementation, and drill scenario timeline and evaluation criteria) would improve the ability of the staff to provide meaningful feedback, and ]
is recommended as a goal for future demonstrations. Additional time should also be allocated to permit follow-up on questions / concerns identified I during the presentations or drill. <
e l The A/M demonstration visit met the established objectives of providing insights into the licensee's implementation / evaluation process, and areas where changes to the draft TI may be needed. Due to the limited nature of the demonstration, and the potential differences in implementation among utilities and NSSS designs, additional demonstrations will be needed in order to form a consolidated view on the industry implementation process, necessary changes to the TI, and the need for any adjustments to the planned inspection process.
e Some level of NRC inspection of severe accident management-implementation appears necessary at each plant to assure that its implementation meets the intent of the program, and does not decrease the effectiveness of emergency response.
}
DISTRIBUTION: SCSB R/F (2) TMartin JLyons SRichards CThomas l DDesaulniers CMiller J0'Brien RB6rrett RHasselberg TPolich SMagruder MModes. RI KBarr, RII JCreed RIII BMurray, RIV Central Files DOCUMENT NAME: COMANCHE.TRP .
I
- t. ,.c . ..n ., m. .u ni, mee. . m in. w c g copy .iinoui .it.enm.nv.nuoto. r - copy .iin .ti.cnm.ni,.ncio.u.. u no copy 0FFICE SCSB:DSSA:NRR l SCSB:DSSAv l BC:SCSBhD0fA BC:PERB:DRPMl4 ADDtDRCf E NAME RPalla:bw RLP JKudrihk W ,\ r s CBerlinge4 h\ CMillerc + , ~ CMtF#
DATE 6/15/97 6/9 1 W Vi 6 M /97 MLN 1// /97 7/T/97 j "1
OFFJCIAERECOR} COPY
i Attachment 1 g
- Carl Berlinger(NRR)
Bob Palla(NRR)
- Jim O'Brien (NRR).
Dave Desaulniers (NRR) l Blaine Murray (R-IV) l l
INDUSTRY l
Marcia Cooper (TVA)
-Jim Weeks (WolfCreek)
Kevin Davison(WolfCreek)
Bob Lutz(Westinghouse)
Nick Valos (Coutca)
Brian McBride (Virgina Power)
Walt Lee (Southern Nuclear)
Tim Kulterman (Northeast Utilitics)
Mark Greene (ABB Combustion Engineenng)
Fred Emerson (NEI)
Gary Winkle (Duke)
- John Small(Duke)
CPSES Lance Terry Jim Kelley Mike Blevins Bobby Lancaster Norman Hood Lynn Wojcik Hugo DaSilva Dave Fuller John Ellard i
9
DEMONSTRATION AGENDA DAY 1 - 05/29/97 .
8:00 A. Welcome - Mike Blevins, Plant Manager (15 min.)
8:15 B. NRC Opening Comments (15 min.)
8:30 C. NEl Opening Comments - Fred Emerson (15 min.)
D. Comanche Peak Steam Electric Station Presentation 8:45 1. Background and E-Plan Review - Norman Hood (15 min.)
9:00 2. SAMG Development and Implementation - Norman Hood (15 min.)
9:15 BREAK (15 min.)
9:30 3. Training' Development - David Fuller (30 min.)
- a. Basis
- b. Population
- c. Extent of training (what training has occurred and continual training)
- d. Self Evaluation 10:00 4. IPE/IPEEE Insight inclusion - Lynn Wojcik (15 min.)
10:15 5. Set Point and Computational Aid Development - Hugo DaSilva (15 min.)
10:30 BREAK (15 min.)
10:45 6. Instrumentation Validation - John Ellard (15 min.)
11:00 7. SAM Drill Overview - David Fuller (30 min.)
11:30 LUNCH (30 min.)
E. Demonstration Drill 12:00 1.1st Drill Briefing 12:30 2.1st Drill Start 1:00 3.1st Drill Critique i
1:30 Break (30 min.) .j
SEVERE ACCIDENT MANAGEMENT DEMONSTRATION
. AGENDA 2:00 3. 2nd Drill to start 3:30 4. 2nd Drill Critique 4:00 5. End of First Day DAY 2 - 05/30/97 8:00 Licensee Presentation (30 min.)
Question and Answer session 8:30 NRC Presentation (30 min.)
Question and Answer session 9:00 NEl Presentation (30 min.)
Question and Answer session l
of
- e
(, _
Comanche Peak Steam !
l Electric Station l
i l
i
! . J . g . A. ).
l Background and E-Plan Review l j Norman Hood .
Emergency Planning Manager l
i !
t 1 I
i l
l i
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Site Specific SAM Background f
l l
- Start of the SAM Effort I
September 1994 NUMARC Workshop
, i j > Development of Task Team
- Reactor Engineering i
l l Operations Support Emergency Planning ;
. J . g . A. ) .
I e I
es Site Specific SAM Background ,
i
> Response Letter to NEl 94-01 Implementation set for July 1997 Site impact i
> Closure Guidance I
i Plan for Adoption of New Information j 3-@ A- ) -
l i i
! Emergency Plan Review l l l l
- E-Plan Discussion i Does NOT address Operation of Plant l Equipment l
-TSC Manag'er responsible for activities j
j required to place the plant in a safe stable l l l condition l l -TSC Engineering Team . . . assess plant status and severity of emergency l
l conditions and develop corrective actions
! . J . g . g. ) .
l Emergency Plan Review
> Procedure Changes l
- . EP Implementing Procedures
- EPP-100, Maintaining Emergency Preparedness
- SAMG Admin. Controls
- 2 year review of Guidelines
- EPP-204, Activation & Operation of the TSC l - Designated the TSC Manager as the Decision Maker l j - Specified that the Evaluator is part of the '
Engineering Team i .
1
. J . o . a. ) .
l i !
l Emergency Plan Review !
i !
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- Procedure Changes (Continued) l i ERGS (exit points)
- ECA-0.0A, Loss of All A.C. Power
- FRC-0.1 A, Response to inadequate Core
- Cooling !
- FRS-0.1 A, Response to Nuclear Power i l Generation /ATWr ;
r No other changes were made to Operation Procedures since they are directed to the SAMGs from the ERGS.
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i . J . e . g. ) .
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SAMG Development and
. Implementation
> SAMG Development Plan Convert WOG Material l Determine unknown setpoints i
- Calculate setpoints
-Develop Computational Aids '
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. i SAMG Development and l
- Implementation j I
l SAMG Implementation Plan ; ,
i
, Develop Training Material Training of ERO Staff I
i Validation Drill
. J . e . g. ) . l 1
L _ _ __ __________________________________________________________________________________________________3
SAMG Development and l .
Implementation
- Westinghouse Owners Group Material 1
, Guidelines and Background Material TraMng Material l i
! Scenario Templates l l
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l 4
t l
l l J 9 A- ) . i i
l i
, SAMG Development and l l Implementation
> Control Room 1 Two Column Format i
- Evaluators ;
Written in a Procedure Format l l
> Computational Aids
- Written as a Calculation
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. J . g . A. ) . ,
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I L_______________-______-_-__-____-___-____. _ _ _ _ _ _ _ ._ _
SAMG Development and -
Implementation l .
> Implementation Activities Summary CR and TSC Guidelines -
ERG /SAMG Interface ,
I
. IPE Insights
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instrumentation Survey j Emergency Plan Review ,
j Training ;
i Validation _
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SAMG Development and l
! Implementation :
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l Other Activities i l
- 10CFR50.54x and y usage for SAM ,
l -
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10CFR50.59 Reviews l l
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TRAINING &
l VALIDATION l
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Dave Fuller
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F WOG Modules l Implementor Decision Maker Evaluator Overview Overview Overview SAG-5 CA-1 i Executive Executive Executive SAG-6 GA-2 Volume -CR Volume - TSC Volume - TSC 4 i SACRG-1 DFC/SCST DFC/SCST SAG-7 CA-3 SACRG-2 Instrumentation Instrumentation SAG-8 CA-4
- SACRG-1/2 SACRG-1/2 SCG-1 CA-5
' l Phenomena Phenomena SC G-2 CA-6 ;
SAG-1 SCG-3 CA-7 l l
SAG-2 SCG-4 '
l SAG-3 SAEG-1 SAG-4 SAEG-2 l
. J . e . g. ) .
i l
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Identify Audience ,
.- Imp!ementorc - Plant Operations
. ROs '
.SROs I
.- Evaluators - Select TSC Engineers
. TSC Engineering Team Coordinator
. TSC Engineering Team (Analysis) l
. TSC Engineering Team (SAMG) l
.- Decision Maker !
l- . TSC Manager !
. J
- D
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Control Room ORG Chart Shrft Manager I
i i I Op Ops Advisor STA Cm Supe ors i
I l Field Support RG Supervisor j
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g AOs f
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I TSC ORG Chart Manager i
I I I I Ops Coord OnRac Eng Tm W Coord Coord '
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l l I l Rad St ERF Ops St "O
- 0" ENS Seq of I Bd Rc Comp Op Bd Rc Comm Events J b A ). l i
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Training Schedule
, > Control Room Training
. 5 shifts (Feb 17 - March 21) i First Day - Overview
. Second Day - Executive Volume, SACRG-1, SACRG-2
> TSC Training l
. April 15 i Required Reading i J . P.) . A. ) . i WOG SAMG Training Materials :
f Learning Objectives ,
- Student Text j Self Assessment
. Answers referenced
- Lesson Plan '
> Exam Bank i
.J.ra.A.). I i
l
l :
CPSES Conversion Tasks l
l
- Objectives
- Setpoints
- Terminology j l
- Equipment / Instrumentation '
Strategies / Lineups /Flowpaths ;
f
- Self Assessment Questions I
- Exam Bank l
- Administrative -
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i i
Conduct of Training j
> Control Room - 2 exams j Overview module ,
. Executive Volume, SACRG-1/2 j
> TSC - 1 exam
. Executive Volume, DFC/SCST, j Instrumentation, SACRG-1/2 i
. Table top Required Reading
. Signature sign-offs
. a . e, . i. 3 i
i i
- -_.----__________________.___-______Q
Hours WOG vs CPSES Control Room WOG CPSES J Overview 2 4 i Exec Vol CR 1 1 SACRG-1 3 2 l
SACRG-2 1 1 ;
. a . e . a. > . !
Hours WOG vs CPSES l TSC WOG CPSES Overview 2 4 ;
Exec Vol 2 2
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DFC/SCST 3 1 5
Instrumentation 2 .5 !
SACRG-1/2 1 .5 Phenomena ? NA l
Table-top NA 2 f ,
. a . 3 . i. > . l l
l
L Validation Conducted 1 tabletop on May 16 )
. Control Room
.TSC Conclusions (all objectives met)
. Control Room exited ERG network to SAMG space
. TSC monitored DFC/SCST
- . TSC directed implementation of strategies
. TSC recognized exit criteria of DFC i
. TSC developed recovery actions for discontinuing i SAMGs -j
. No impact on E-Plan ;
J @ A+ ) . l I
i Future ;.
i i
> Refresher Training l
. annually as part of EP Training
- Table-tops ;
every other year
/
I
. . J . g . g. ) .
IPE / IPEEE INSIGHT INCLUSION I
I
. J . $ . d. ) .
l.
Lynn A. Wojcik ,
I l Engineering Analysis Supervisor I
IPE results used to determine: l i
l
- Possible challenges to containment fission !
product boundaries i
Dominant severe accident scenarios f
i l
- g . g. ) .
- . j l
k
CPSES Severe Accident Management Guidelines l .
I
- Contain plant specific insights l' l
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- J 9 A- ) -
i Major generic insights regarding strategies, systems capabilities, and equipment alignments . ;
i
- IPE input from utilities j i
. J . e . A. ) . l i ..
l
l
. i WOG SAMG Input from Utilities 1 4
I
- Fission product release pathways )
- Dominant core damage sequences and associated failures
> IPE " insights" !
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! IPE identified " vulnerabilities" j I
l J 9 A >- l
. , i f
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i IPE Insights influencing WOG j i
! SAMG Development ,
i 1
Plant specific equipment alignments 4 I
- Isolation of non-functioning " safety systems" i i
,
- Potential for limited use of e,quipment ;
j
- Non-standard cross-ties of systems j j External reactor vessel submergence l I
l i Hydrogen burns i
I ,
s A i
l J >- ;
IPE Insights influencing CPSES SAMG Development l
l Procedural and design improvements I
Unique plant safety features i
1 Unique containment safety features i '
! i
. _j . 3 . A . ) .
f h
Unique Plant Safety Features
> station service vvater system
- Component Cooling Water System Electric power offsite interface 1 !
! Auxiliary Feedwater System i !
i i
Emergency Core Cooling System injection l . ,_]. @ . & . ) . j
.- \
.. i Unique Containment Safety I Features l 1
$ l b l
> Containment free volume
> Reactor cavity floor area Drain to reactor cavity
! 1 I
i ._l S A >-
i l
- Setpoint (SP) and Computational
{
Aid (CA) Development Hugo da Silva i
t
- 1. Common Features of SPs and CAs I
- 2. CA Development and Results ,
- 3. Aspects of SP Development !
- 4. Conclusion and Summary i
, J O A- ) .
I Common Features of SPs and CAs !
l
> Both follow the generic WOG framework i i closely
> Each CPSES SP and CA has a one-to-one WOG generic counterpart ;
> Determination process and resulting values i I
formally documented in calculation package ,
. J . e . A. ) .
. CA Development ,
l l
- CA calculation package follows WOG guidance l . Basis
! . Usage i.
. Assumptions
. Calculation Process ;
. Results
> Results section is the actual CA in graphical j l
form. l l
. J . e . g. ) . !
l I
I CA Development l
- CA-1 RCS Iniection to Recover the Core l
> CA-2 Injection Rate for Long Term DH Removal j
> CA-3 H2 Flammability in Containment l CA-4. Volumetric Release Rate from Vent l CA-5 Containment Water Level and Volume ;
- CA-6 RWST Gravity Drain l
> CA-7 H2 Impact when Depressurizing Containment
. J . e . g. ) .
t
I SP Development l
- SP calculation package provides for
' l
. Usage
. Basis {
{'
, . CPSES value determination
- . . L13 - NPSH for start-up feed-water pumps l I
. L14 - UHS level to supply NPSH to SW pumps ;
. HO1 - Concentration that results in post-burn temp that fails recombiners l \
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Parameter Availability
- EP Display
- Plant Computer
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- PC-11 Computer
> Main Control Board I
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4 Parameters l > S/G Water Level: WR & NR EP= Display
> S/G Pressure: EP Display
> RCS Pressure: Pzr Pressure & ECCS l Flowrates =EP Display, WR RCS Pressure & j Accumulator Pressure = Plant Computer
> Core Temperature: CET, Th, Tc & Sat Margin =
EP Display
> Rx Water Level: RVLIS & WR Neutron Flux EP Display, SR= Plant Computer J e A- ) .
Parameters
> Containment Water Level: Recirc Sump Level
& RWST Level =EP Display .
- Containment Hydrogen: EP Display
- Containment Pressure: NR=EP Display, WR= Plant Computer
> Containment Temperature: EP Display i > Radiation Levels: HR Containment & Stack Monitors =EP Display, other monitors on Plant
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Severe Accident Demonstration 05/29/97 I. Objectives Use SACRO-1 for initial Control Room Response Use SACRG-2 for transition to the TSC Use SAG-1 to feed to the steam generators Use SAG-3 to evaluate RCS injection strategies Use SAG-4 to evaluate containment injection strategies Use CA-6 to evaluate gravity draining the RWST to contamment Use SCO-1 to mitigate fission product releases Use SAG-6 to evaluate contaimnent pressure control strategies I se S AG 7 to evaluate a hydrogen control strategy Use CA-3 and/or CA 7 to evaluate containment hydrogen conditions Use SAEG-2 to look at long term core cooling and long range plan for turning the plant back to Operations II. ACCIDENT SCENARIO IN ERGS, PRIOR To UsE OF SAMG:
The event was initiated by loss of all feedwater followed by a loss of all power to emergency A.C. buses. The control room will be in ECA-0.0, " Loss of All AC Power". Since auxiliary feedwater was not available, it is anticipated that the steam generators will not be depressurized to attempt to cool the RCS. In ECA-0.0, all equipment is placed in pull to lock in preparation for restoration of power. Therefore, the time of core overheating and transition to the SAMG is dependent on another event occurring since the RCS is still at NOT and NOP, the accumulators are full and the steam generators have either reduced inventary or are dry. In order to facilitate the use of the SAMG, there was some significant RCS leakage, small break LOCA. Since there is no ECCS available the core uncovers and the CET temperatu-e increasc ;o greater than 1200 degrees which drives the Control Room staffinto SACRO-1.
III. SCf.NARIO:
Loss of all feedwater and loss of all station A.C. power to emergency busses with a small break LOCA.
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l IV. DRILL SCENARIO INITIAL CONDITIONS:
l DFC parameters that will be outside of acceptable range (i.e., either above of below set points as l appropriate): ,
SG Level Core Temperature Fission Product Release Containment Level Containment Pressure Containment Hydrogen SCST Parameters outside of acceptable rance:
Fission Product Release Instrumentadon Failures:
Required: Core exit thermocouple, RVLIS and hot leg RTDs
- . .._ .. .. .._... ... . . . . ... , a..
IV.
DRILL SCENARIO INITIAL CONDmONS (CONUNUED)
Initial Conditions at Initiation of SAMG Table Top Drill Plant Parameter Value Fmjjpmegg Statui
,, Secondary Side SG Level < 31% NR in All SG AFW Motor Driven Not Asailable Turbine Driven SG Pressure 1100 psig (ARV st. pt.)
MaaFW Not Available Total Feedwater Flow 0 Condensate Pumps Not Available Steam Line Radiation Normal SG Atmospheric Relief Available / Operating SG Steam Dump Not Available / Closed i MSIV Available / Closed Reactor Coolant System
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RCS Pressure 2250 psig Charging l
Not Availabic RVLIS Pull Charging Pumps Not Available I Core Exit Thermocouple 588 F St Pumps Not Available RHR Pumps Not Available _
RWST Level Pull Accumulator Available Accumulator Pressure 600 peig PZR PORVs Available / Closed
$1 Flow 0 PORV Block Valves Available / Open Charging Flow Emergency Boration Head Vent Available / Closed RCPs Not Available
,, Contamment Containment toel 0 ft Containment Spray Not Available Containment Pressure 1.5 Dsig Containment Fan Coolers Not Available containment Temperature 220 F (Saturation)
Containment Hydrogen < 1 % (dry) Hydrogen Recombiner Not Availabic I
Conminment Spray Flow 0 rpm Continunent Tsolation Available / Complete Containment Radiation 1.5 R/hr (Norman l
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,; ; ;; --;; . . z; et V. EXPECTED ROUTE THROtlGH SAMG:
- Enter SACRO-1 due to CET temperature exceeding 1200 degrees.
- Enter SACRG-2 when the TSC is ready to take over SAM
- Enter SAO-1: immediate exit with no equipment available on initial pass
- Enter SAG-3: cvaluate gravity draining RWST to the RCS, containment presstvc may exceed back-pressure for gravity draining _
- Enter SAO-4 : evaluate gravity draining RWST to containment. containment pressure may exceed back-pressure for gravity draining
- Enter SAG-6: immediate exit with no additional equipment available
- Enter SAG-7: immediate exit with no additional equipment available
- Possible trigger of DFC setpoint for containment hydmgen
- Enter SAEG-1: evaluate long tenn concerns
- Continue cycling through the DFC
- Source ofpower is restored
- Enter S AG-1: Evaluate usage of newly restored feed capability, may be superceded since there is no differential pressure and tube creep rupture not a real concern
- Enter SAG-1: Evaluate usage of newly restored RCS injection capability
- Containment hydrogen exceeds DFC setpoint; the CA-7 region attained is at the option of the scenario developer as long as the SCST is not used. An evaluation of a hydrogen control strategy will be made Enter SAEG-2: evaluate exiting fmm S AMG (this is done after a time jump in the acenario)
- Drill ends VI. SCENARIO ACTIVITIES:
Scm.<Rio RcautRcoACTIVITIES:
Use of RWST gravity drain (or other plant specific means ofinjecting water into the containment or RCS)
- Restoration power source
- ' Containment hydrogen above DFC setpoint level
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,ea Demonstration Self Assessment Control Room
- 2. Need more controllers in the simulator to pass data
- 3. Need better data to give the operators during scenario
- 4. Need to add the priorities of SAMGs in the CR executive volume
- 5. Operator still like using the simulator better than a regular table top TSC
- 1. Need to evcluate adding safety chill water to restoration SAMG
- 2. Tab the setpiont and computational aid documents
- 3. Add alternate method to get fire water into the containment spray header (SAG-4)
- 4. Need a better disp'ay to track DFC and SCST values
- 5. Implemented a strategy that did not take CR action but did not update status board
- 6. Needed better and more timely rad. data from the EOF role player EE
- 2. Communication between facilities was good but the dead time appeared to the operators as the TSC not doing anything this specifically pertains to the hydrogen discussion Other Improvements
- 1. Strategies form liked by the operators
- 2. Priorities hard copy l
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