ML051090141
| ML051090141 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 03/17/2005 |
| From: | Duke Energy Corp |
| To: | Office of Nuclear Reactor Regulation |
| Olshan L N, NRR/DLPM, 415-1419 | |
| Shared Package | |
| ML051090334 | List: |
| References | |
| Download: ML051090141 (27) | |
Text
/lDuake Tornado Licensing Basis and Mitigation Strategy Kick-off Meeting 99 999 9 9f 9-TTT -TTTTTg Oconee Nuclear Station March 17, 2005 1
Duker Agenda L Introductions Li Objectives L Oconee Licensing Basis Insights LiJ\Safety Review Li Design Basis Upgrade Initiative Summary L Potential Modifications Cl Closing Remarks 2
^ Duke Goals & Objectives bl~e~rig I c * ,7 7 - -
EJ Engage with NRC to find and implement an effective solution to the Oconee Tornado licensing basis and mitigation issues L Provide an overview of licensing basis insights from an Oconee perspective l Communicate results of the Safety Review performed relative to the list of NRC concerns E Move beyond differences in interpretation of the Oconee current licensing basis 3
DuEke Goals & Objectives LI Establish a framework of cooperative issue resolution with NRC
/ What changes will bring our two views of the Current Licensing Basis (CLB) closer together?
/ Craft a LB both Duke and NRC agree on, and most importantly, stands the test of time.
LI Provide an overview of modifications under consideration to eliminate or decrease tornado vulnerabilities Li Provide periodic status to NRC of Duke activities to strengthen the licensing basis both in the short-term and long-term. Establish a schedule to support these discussions 4
Duke Oconee Licensing Basis Insights Cl Original LB (1973 - Unit 1; 1974- Units 2 and 3)
Oconee's initial operating license pre-dates the GDCs, SRPs and the NRC (AEC).
/ several diverse and physically separated power sources V abundant supply of water (up to 37 days)
/ protected station ASW pump and power supply v/ no single failure requirements v/ tornado does not occur with nor can not cause a LOCA El Issues not addressed with respect to tornadoes in original FSAR/SER:
V Primary make-up capabilities X RCP seal LOCAs V PORV/PRV failures Iv SG tube stresses 5
luke Oconee Licensing Basis Insights wnergy 1 .
EJ LB: 1974-1994
/ NUREG 0737, ll.E.1. 1, "Short-term Auxiliary Feedwater System Evaluation" a/ SSF begins operation LI LB: 1995
/ Primary make-up capabilities added to UFSAR due to industry RCP seal LOCA concerns.
- SSF RCMU
/ Added clarification to UFSAR 3.2.2 based on IPEEE risk results.
6
Duke e Results of Safety Review INAMIMants MINIM-111 0- ;47! I Mly?-`M;Vz Mi -rM!i. 7-7-2,,.,7-.-?:! 1 --
El A Safety Review was performed for each issue identified in the "Licensing Basis Discrepancy" document received from NRC.
El The Oconee position is that we are in compliance with CLB. Therefore, an operability determination in accordance with GL 91-18 did not apply.
Li The CLB is based on diversity and defense in depth, not deterministic.
/ Concerns articulated by NRC are tornado vulnerabilities, not licensing basis conformance deviations GL 88-20 drove non-SRP plants to perform IPEEE evaluations The IPEEE Technical Evaluation Report (TER) for Oconee accepted the IPEEE's conclusion that Oconee had no severe accident vulnerabilities that needed to be addressed via the 10CFR 50.109 backfit process
/ GL 95-04, System Evaluation Process (SEP), contains a table that supports the Oconee position regarding IPEEE tornado strategy
Duke Results of Safety Review mnergy U NRC concerns list evaluated v Results:
- Safety evaluation performed. Based primarily on low-risk impact of the items from the list, Oconee is safe.
- UFSAR needs to be clarified.
Action:
- Submit an LAR to clarify/strengthen UFSAR Section 3.2.2 U LAR Details V Traditional LAR submittal w/risk insights (but not a classic risk informed LAR per RG 1.1 74)
Clarify actual mitigation strategy
- Limitations are described/quantified using risk
- Overall tornado risk discussed 8
ZDuke Design Basis Upgrade Initiative er Modifications L Presentation addresses phase I of the mod process v Investigate design concepts v' Evaluate feasibility and constructability
/ Develop order of magnitude cost estimates 1L Mod proposals outlined in this presentation v/ Developed as an aid for the vendors v/ The optimum design concept resulting from phase I of the mod process may differ significantly from the modification proposals outlined in this presentation 9
Duke Design Basis Upgrade Initiative e Modifications 1 Scope Enhance natural phenomena barriers Improved alternate safe shutdown path
- Using Station ASW and HPI
- Upgraded power supplies
- Control from the main control room
- Significantly reduces tornado damage frequency 10
ZDuke Design Basis Upgrade Initiative e Modifications IN I it.. -,/, , _. .
Li Scope (cont'd)
Enhance natural phenomena barriers
- Upgrade north Unit 3 Control Room Wall
> Missiles addressed via TORMIS submittal
> Wind/DP to be addressed with additional shielding
- Upgrade elevated SSF trench to withstand missiles
- Upgrade west pen and cask decon room walls for missiles, wind, and DP 11
Duke Design Basis Upgrade Initiative CEnergy Modifications IJSensitive Information (withheld per SECY 04-01 91) 12
Duke Design Basis Upgrade Initiative e Modifications LJSensitive Information (withheld per SECY 04-0191) 13
Duke Design Basis Upgrade Initiative energy Modifications LIS'ensitive Information (withheld per SECY 04-0191) 14
Duke Design Basis Upgrade Initiative Energy Modifications D Scope (cont'd) v/ Alternate safe shutdown path Station ASW
> Upgrade Station ASW to high pressure system Eliminates need to manually operate atmospheric dumps Improves tube to shell differential temperatures
> Provide start and flow control and indication in control room Response time reduced from 40 minutes to less than 15 minutes Eliminates PORV, PSV challenge Improves three unit control capability 15
Legend \/ Cm )3ASW-11 3ASW-12 Existing Piping to Remain b . ,
- New or Replaced Piping .C Pr - I l51°U3 HPIP's SStF-ASVI Return to U2 CCW Inlt Proposed Station ASW Upgrade 16
Design Basis Upgrade Initiative ergy Modifications
- i. --. '- , 2 I Sensitive Information (withheld per SECY 04-0191) 17
Dueke Design Basis Upgrade Initiative er Modifications Cl Scope (cont'd) v New Station ASW switchgear loads
- High pressure ASW pump & system
> Isolation Valves
> Flow control valves
> Flow instrumentation
- One HPI pump per unit & system
> Provide remote transfer to new ASW switchgear for one HPI pump/unit
> Provide sufficient power and cubicles for future equipment (next slide) 18
DuIke Design Basis Upgrade Initiative er Modifications WHIM - _ = 7777e r r . .+
Ii Scope (cont'd) v' Alternate safe shutdown path (cont'd)
HPI (to follow Station ASW and electrical upgrades)
> Provide hardened power supply and remote control for BWST suction valves RCP seal flow control valves Reactor head and high point vent valves for letdown Pressurizer heaters 19
ZDuke Design Basis Upgrade Initiative er Modifications Li Proposed Schedule v' Duke completes phase I of the mod process
- Natural phenomena barriers
> Complete design concepts- May 2005
> Test of concepts if necessary- End of 2005
- Station ASW and electrical enhancement- End of 2005
- HPI upgrade- to follow Station ASWand Electrical Upgrades Duke initiates final design package- early 2006 20
Duke Design Basis Upgrade Initiative Energy Modifications O Status v Natural phenomena barriers
- Contracted Fluor to develop design concept
@ Past experience at Hanford
- Design concept, feasibility, order of magnitude cost on target for completion by May 2005
- Testing targeted for completion by end of 2005 if necessary 21
Duke Design Basis Upgrade Initiative Energy Modifications El Status (cont'd) v Station ASW
- Technical Scope Requirement document completed
- Request for quotes sent to vendors this week
/ Upgrade power supplies e ONS mod teams in place
- Draft Technical Scope Requirement document completed
- Request for quotes to vendors to be sent out by the end of March 22
XDuke Design Basis Upgrade Initiative 1119TV Modifications Li Challenges
/ Accelerated schedule e Feasibility/design for SG Replacement took several years a Large, complex project
- Scarce resources for oversight
- Working with new vendors
/ Technical Challenges
- Providing alternate or upgraded power supply to new ASW SWGR
- New cable runs to cable spread room
- Avoiding adverse impact on existing SSCs
- Implementation- CT5, Standby Bus and Station ASW are 3 unit systems 23
/ Graded approach to a technical review.
/Could be eng li supv or couMd he/
' / ~MRPT t 'phase review./
anl E /-/Preliminary scope.
ine Ible Yes describing 'what is anageme
_ soluti .sobtains Yess the s teen\ nierim cion No dosired and _ od Actvate MRPT Discrelion Io No at onInput. and ap rnt Required? relative priority Is yImplement asa makes produced and sent enieha recommendrlion. _ to Mod Eng. Mod N Engineering Yes Bac to;PIP and Documr.n1 Interirnm Plant Eng for other Dsign . ion' l action in the l
/souions to be tad tiHeatth Report and l mo Mod Eng creates Y/ pnoblem /implement action cope proposa procurement spec, be deveoped request for henu proposat Plant Eng n I*Yes Mod Eng sends 4 performs rfo >,package to evaluallon I Mod Eng creates vendors for scope and proposal associated cost development I PIP id.lifies a l Yestimate IMod En ere Mod Eng reviews Mod &proposals ng erfrms rojct e and 14 evaluation lea rthe Mod Eng creates selects best'.
aluanion. Evaluate Impact of scope. associated Plus Senior Emergent Mod on cost estimate.
Management s= Scheduled Work priorty. and l Discreion Discroion Nschedule. Ilto Sends Plant Eng. for review.
Plant Eng.
ERRT develops Reviews and appropriate approves Engineering Change R No MRPT performs
/Acknowlde \ review for Scheduln Ipacs > prioritizaton l
\ nd Aclivale / l budgeting, slottingl MOO and final decision.l Back to PIP and v od egi r Ye s No Plant Eng for other Phase I of the Mod Process vn bpginhase pss solutionseto 24
Duke Design Basis Upgrade Initiative e Modifications
~nv.. - -. :- ,..- ..... .
El NRC concerns being addressed Natural Phenomena Barriers
- New power supply from Station ASW Switchgear to battery chargers in Auxiliary Building
- Upgraded west penetration and cask decon rooms
- Upgraded unit 3 north control room wall
- Upgraded SSF trench
- Eliminating manual actions in turbine building to open atmospheric dumps 25
Design Basis Upgrade Initiative nergy Modifications J NRC concerns being addressed (cont'd)
Mitigation system functionality
@ Reduces PORV and PSV challenge
- Significantly reduces steam generator tube to shell differential temperatures
- Remote and reliable flow control of station ASW to all three units
- Provides for hot shutdown capability using HPI and alternate letdown paths (to follow Station ASW and electrical upgrades) 26
Duker Closing Remarks
-5 .- - :
Oconee is safe today relative to tornado risk Oconee will add clarity and detail to the existing LB contained in UFSAR.
Modifications are being aggressively pursued to address vulnerabilities and improve overall tornado mitigation strategy for the future.
Oconee has a strong desire to proactively engage with NRC to resolve these issues and implement satisfactory solutions.
Questions Next meeting 27