ML20249B436

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Summary of 980514 Meeting W/Duke Energy Corp Re Info Related to Ice Condenser Issues,Ice Weight Redistribution & Reduction & Block Ice Utilization.List of Participants & Handout Provided by Util,Encl
ML20249B436
Person / Time
Site: Mcguire, Catawba, McGuire  Duke Energy icon.png
Issue date: 06/17/1998
From: Rinaldi F
NRC (Affiliation Not Assigned)
To:
NRC (Affiliation Not Assigned)
References
TAC-MA1785, TAC-MA1787, TAC-MA1952, TAC-MA1953, NUDOCS 9806230101
Download: ML20249B436 (33)


Text

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June 17, 1998 LICENSEE: Duke Energy Corporation FACILITY:. McGuire Nuclear Station, Units 1 and 2 Catawba Nuclear Station, Units 1 and 2

SUBJECT:

MEETING

SUMMARY

- MEETING OF MAY 14,1998, REGARDING ICE CONDENSER ISSUES (TAC NOS. MA952, MA1953, MA1785 AND MA1787)

On May 14,1998, the staff met with Duke Energy Corporation (DEC) personnel to discuss information related to the following ice condenser issues: ice weight redistribution and reduction, and block ice utilization. The meeting was scheduled to communicate DEC plans for future changes to the Technical Specifications for the McGuire and Catawba nuclear stations.

Enclosure 1 lists the meeting participants. Enclosure 2 is the handout provided by DEC. 1 ORIGINAL SIGNED BY: ,

Frank Rinaldi, Project Manager Project Directorate ll-2 Division of Reactor Projects - 1/11 Office of Nuclear Reactor Regulation Docket Nos. 50-389,50-370, 50-413, and 50-414

Enclosures:

i

1. Meeting Attendees
2. DEC Handout cc w/encts: See next page 1 e-mail w/ encl.1 Hard Coov i SCollins/FMiraglia KCampe Docket Fiie l BBoger BMartin PUBLIC JZwolinski NEconomos PD 11-2 Rdg.

- HBerkow MTschiltz FRinaldi LBerry LPlisco, Ril OGC TMartin COglo, Ril ACRS RBenedict PTam Licensee & Service List i JPulsipher 1 CBerlinger I j i \

9806230101 990617 ib~ ~ " ',E!@' b i d sCtGray PDR ADOCK 05000369 P PDR TO receive a copy of this document, Indicate in the box: "C" = Copy without attachment / enclosure "E" = Copy with attachment / enclosure "M" = No copy OFFICE PM:PDil-2 m LA:PDil(2W D:P Q F j l NAME FRinaldi:cn T//11 Berry .\.(\ / HBerkW DATE 6 //T/98 /.

3 /15 /98" s //L/98 / /98 = / /98 / /97 DOCUMENT NAME: G:\MCG0lRE\MTG.lCE OFFICIAL RECORD COPY 1 L _ _ _ _ _ _ _ - _ _ - _ _ _ - _ _ -

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p f "%,,% UNITED STATES g NUCLEAR REGULATORY COMMISSION

, WASHINGTON, D.C. ageeHoot

% June 17,1998 LICENSEE: Duke Energy Corporation

! FACILITY: McGuire INc! car Station, Units 1 and 2 Catawba Nuclear Station, Units 1 and 2 l

SUBJECT:

MEETING

SUMMARY

- MEETING OF MAY 14,1998, REGARDING lCE CONDENSER ISSUES (TAC NOS. MA952, MA1953, MA1785 AND MA1787)

On May 14,1998, the staff met with Duke Energy Corporation (DEC) personnel to discuss information related to the following ice condenser issues: ice weight redistribution and reduction, and block ice utilization. The meeting was scheduled to communicate DEC plans for future changes to the Technical Specifications for the McGuire and Catawba nuclear stations.

Enclosure 1 lists the meeting participants. Enclosure 2 is the handout provided by DEC.

%#-n 6O Frank Rinaldi, Project Manager Project Directorate 11-2 Division of Reactor Projects - 1/11 Office of Nuclear Reactor Regulation Docket Nos. 50-369, 50-370, 50-413, and 50-414 Enclosurcs:

1. Meeting Attendees
2. DEC Handout cc w/encls: See next page -

l l

' McGuire Nuclear Station Catawba Nuclear Station ,

cc:

Mr. Paul R. Newton Mr. Richard M. Fry, Director Legal Depa'tment (PB05E) Division of Radiation Protection Duke Energy Corporation- North Carolina Department of 422 South Church Street Environment, Health, and Charlotte, North Carolina 28242-0001 Natural Resources 3825 Barrett Drive County Manager of Mecklenburg County Raleigh, North Carolina 2760g-7721 720 East Fourth Street Charlotte, North Carolina 28202 Ms. Karen E. Long Assistant Attorney General Mr. Michael T. Ccsh North Carolina Department of Regulatory Compliance Manager - Justice Duke Energy Corporation P. O. Box 62g McGuire Nuclear Site Raleigh, North Carolina 27602 12700 Hagers Ferry Road Huntersville, North Carolina 28078 L. A. Keller Manager- Nuclear Regulatory J. Michael McGany, Ill, Esquire Licensing Winston and Strawn Duke Energy Corporation 1400 L Street, NW. 526 South Church Street Washington, DC 20005 Charlotte, North Carolina 28242-0001 Senior Resident inspector Regional Administrator, Region ll c/o U. S. Nuclear Regulatory U.S. Nuclear Regulatory Commission Commission . Atlanta Federal Center 12700 Hagers Ferry Road 61 Forsyth Street, S.W., Suite 23T85 Huntersville, North Carolina 28078 Atlanta, Georgia 30303 Mr. Peter R. Harden, IV Elaine Wathen Account Sales Manager Lead REP Planner Westinghouse Electric Corporation Division of Emergency Management i

Power Systems Field Sales 116 West Jones Street P. O. Box 7288 Raleigh, North Carolina 27603-1335 Charlotte, North Carolina 28241 Mr. T. Richard Puryear Dr. John M. Barry Owners Group (NCEMC)

Mecklenburg County Duke Energy Corporation Department of Environmental 4800 Concord Road Protection -, York, South Carolina 2g745 700 N. Tryon Street Chariotte, North Carolina 28202 L

4 McGuire Nuclear Station Catawba Nuclear Station cc:

Mr. M. S. Kitlan North Carolina Electric Membership Regulatory Compliance Manager Corporation Duke Energy Corporation P. O. Box 27306

,. 4800 Concord Road Raleigh, North Carolina 27611 l York, South Carolina 29745 Senior Resident inspector North Carolina Municipal Power 4830 Concord Road Agency Number 1 York, South Carolina 29745 1427 Meadowwood Boulevard P. O. Box 29513 Mr. G. R. Peterson i

Raleigh, North Carolina 27626-0513 Site Vice President l Catawba Nuclear Station County Manager of York County Duke Energy Corporation

- York County Courthouse 4800 Concord Road York, South Carolina 29745 York, South Carolina 29745 Piedmont Municipal Power Agency Mr. H. B. Barron 121 Village Drive Vice President, McGuire Site

~ Greer, South Carolina 29651 Duke Energy Corporation 12700 Hagers Ferry Road Saluda River Electric Huntersville, North Carolina 28078 P. O. Box 929

. Laurens, South Carolina 29360 Max Batavia, Chief j Bureau of Radiological Health South Carolina Department of Health and Environmental Control 2600 Bull Street I Columbia, South Carolina 29201 4

L .

LIST OF PARTICIPANTS MEEIING WJTH DUKE ENERGY CORPORATION - ICE CONDENSER SCOPING MEETING MAY 14.1998 r

Name Affiliation Frank Rinaldi NRC/NRR/DRPE/PDil-2/PM-McGuire David Lochbaum Union of Concerned Scientists Gregg Swindlehurst Duke Energy Corporation Robert Benedict NRC/DRPM/PECB Bob Morgan Duke Energy Corporation Bill Lifsey Duke Energy Corporation Tom Yadon Duke Energy Corporation Mark Holmes Duke Energy Corporation

' Richard Spada Duke Energy Corporation Michael Wilder Duke Energy Corporathn Jim Pulsipher NRC/NRR/ Containment Systems Branch Carl H. Berlinger NRC!NRR/DSSA/SCSB Kaz Campe NRC/NRR/DSSA/SCSB Bob Martin NRC/NRR Ice Condenser Point of Contact Nick Economos NRC/ Region ll (Phone Connection) l i

Enclosure 1 l

/

4 . . .

$$. A ad,aw.y tw ICE CONDENSER LICENSING AMENDMENT SCOPING MEETING May 14,1998 Introduction / Duke Power Attendees

  • Gregg Swindlehurst, Manager- Safety Analysis Section
  • Tom Yadon, Engineer - Safety Analysis Section
  • Mark Holmes, Engineer - Safety Analysis Section
  • Bob Morgan, Manager - Equipment Engineering
  • Rich Spada, Engineer - Equipment Engineering
  • Bill Lifsey, Engineer - Equipment Engineering
  • Mike Cash, Manager - Regulatory Compliance
  • Mike Wilder, Engineer - Regulatory Compliance 2

1 Enclosure 2

Agenda

  • Introduction & - Mike Cash Purpose
  • Tech. Spec. Based on - Rich Spada Ice Mass Projection
  • lee Weight Reduction - Tom Yadon i
  • Large Scale Block ice - Bill Lifsey implementation Mark Holmes Approach Gregg Swindlehurst 3

Agenda (Cont'd.)

  • Asymmetric ice - Rich Spada Distribution ' Tom Yadon
  • Conclusions - Mike Cash 4

2

Meeting Goal

= Communicate severalice Condenser related projects that have been underway at Duke .

These projects have focused on reducing maintenance and outage cost while maintaining nuclear safety focus

. Obtain ONRR Staff feedback.

5 Overall Project Goals a Outage length reduction is a business goal.

  • Outage length evaluations have focused on establishing economic durations, that meet all regulatory requirements, while maintaining the highest standards for nuclear and personnel safety.

= lce condenser maintenance was identified as one area where initiatives are necessary to achieve the outage length goals at Catawba and McGuire Nuclear Stations.

  • Reduce overall maintenance cost while maintaining a highly reliable ice condenser 6

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TECHNICAL SPECIFICATION BASED ON ICE MASS i PROJECTION 7 (

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i Ice Condenser Design and Function

  • The Ice Condenser is arranged in a 300 degree arc just inside the containment vessel and is part of the boundary between lower and upper containment.
  • Steam released from a postulated event causes a pressure differential between lower and upper containment.
  • Steam passes through the Ice Condenser by entering at the lower inlet doors flowing through the ice bed and condensing.

Ice Condenser Purpose l j

= Provide a flow path from lower to upper containment for steam released from a LOCA or high energy line break

  • Provide an adequate supply of ice for thermal energy absorption to limit containment pressure and temperature in the event of a LOCA or high energy line break
  • Provide melted ice to lower containment with the required chemistry to contribute to ECCS recire inventory 10

d Ice Condenser Lower and Upper Plenum Details j  :::=

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  • Ice Condensef Upper Pienum Il Maintenance Challenges a Sublimation rates are higher near the crane wall as compared to the center of the ice bed.

= Basket ice replenishment is required more frequently in the high sublimation areas. These areas require extensive cleaning due to frequent flake ice loading.

  • Current Ice Condenser maintenance efforts l exceed what is necessary to maintain a highly j reliabic ice condenser. l t

l 12 6

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ICEMAN

  • ICEMAN is an ICE Condenser Management system designed by Duke Power Company and written by Framatome Technologies.

- Provides for scheduling and managing ice condenser maintenance activities

- Provides database management for ice weight data and ice basket configurations

- Calculates sublimation ratcs for individual baskets based on historical data l

- Sublimation rates are updated each time a new basket weight is acquired.

l This provides basket weight projections during refueling outages.

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. c Ice Basket Weighing and Data

  • Three types of data are acquired on a regular basis.

- Generally all baskets are weighed at the start of a refueling outage to provide an as-found weight

- All replenished baskets are weighed after being loaded to provide r> replenished weight

- Basks , are weighed periodically as required by Tech Specs

  • Baskets are identified by bay, column and row 15 Ice Basket Weighing and Data (cont'd.)
  • Every basket has a complete weight history stored in ICEMAN for calculating sublimation rates.
  • Sublimation rates are used for projecting future basket weights as well as checking as-found weights as they are input into the database.

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  • Time AAowance X a Ceert Tech Spea Sweemahon A4ader o = Propobon as ed Teen spee ammehen Moses 17 Current Tech Specs
  • Based on the assumption that sublimation rates are a percentage of basket weight and are uniform throughout the ice bed
  • Uses a statistical sample of 144 ice basket weights to predict current ice bed mass 18 9

Current Tech Specs (cont'd.)

  • Use a constant ice weight allowance applied to each ice basket to determine adequate ice mass for the subsequent surveillance period

. Could be improved by taking advantage of operating experience, computer based technology and current maintenance practices 19 Tech Specs Based on Ice Mass Projection

  • Based on the knowledge that sublimation rates are independent of basket weight and vary from crane wall to annulus wall baskets
  • Would use 100% of current basket weight data to determine current ice bed mass 20 ,

i 10

Tech Specs Based on Ice Mass Projection (cont'd.)

  • Would use historical data to predict future weights to ensure each individual basket remains above design requirements

= Prediction periods would extend beyond the subsequent fuel cycle to provide an appropriate weight allowance for each basket 21 Projection Reliability

  • ICEMAN projections have proven to be conservative over a number of operating cycles.

- Sublimation rate calculations include historically highJr sublimation periods which results ir conservative projections.

- A review of recent outage data found ICEMAN projected l

ice weights within measurement accuracy or conservatively

! projected the weights in 98% of measured bc.skets.

22 11 1

1 I

I Licensing Requirements

  • Technical Specification amendment under 10 CFR 50.90 No revision to Topical Reports 23 DM __

ICE WEIGHT OPTIMIZATION 24 12

l-Benefits

  • Support outage duration goals through a reduction in ice condenser outage maintenance workload.

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  • Each 20 to 30 baskets requiring replenishment l ,

increases ice condenser outage duration by one l

day.

l 25 Benefits (cont'd.)

  • The previous CNL Units 1 & 2 and MNS Units 1 &

2 ice condenser outage scope involved replenishment of 323,395,565, and 440 baskets respectively in order to conservatively manage basket life cycles.

  • lee weight optimization will reduce the number of unload / reload cycles on ice baskets with no impact on containment safety margin.

'P 26 13

I Current Ice Condenser Containment Response -LOCA Analyses

  • Short Term (Blowdown)- Performed with W TMD code analysis

- Short duration

- Methodology based oi. /%ltz Mill Test Facility program (yy)

- Documented in WCAP-8zCe

- Sensitivity results show large margin with increased blowdown, deck leakage

- Result is 7.67 psig (CNS) / 7.8 psig (MNS)

- Remains valid 27 Current Ice Condenser Containment Response -LOCA Analyses (cont'd.)

  • Long Term (Post -Ice Melt)- Performed with GOTHIC 4.0/ DUKE code analysis

- Long duration >2 hours

- Methodology based on Battelle Test Facility program

- Documented in DPC-NE-3004-PA (Approved by NRC SER dated 9/6/95) l

- Mass and energy release data taken from RELAP5/ MOD 3.1 DUKE analyses

- includes short term response

- Result is 12.26 psig (CNS) / 12.78 psig (MNS) 28 14 J

Current Ice Condenser Containment Response -LOCA Analyses (cont'd.)

  • Long Term (Post -Ice Melt)- Performed with GOTHIC 4.0/ DUKE code analysis (cont'd.)

- Uses margin in DPC-NE-3004 PA results

- Additional weight reduction can be achieved by allowing steam generators to fill to a higher post-LOCA level

- Plant modification to start turbine-driven auxiliary feedwater pump required

- Realignment of ECCS valves required 29 Summary of Optimization

  • In assessing containment response following an accident using RELAP5/ GOTHIC codes, long term peak pressure was decreased.

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  • This allows optimization of the required ice mass without affeeling the margin of safety for containment structures.

I 15

Licensing Requirements

! aNo revision to Topical Reports l

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LARGE SCALE BLOCKICE IMPLEMENTATION 32 16

Definition of Block Ice l

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  • Hydraulically compressed cylindrical blocks measuring approximately 10-7/8 inch in diameter and 15 inches long l

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  • Blocks are composed of standard flake ice and a small quantity of borated water
  • Each ice block weighs in the range of 42 to 45 pounds 33 I

Definition of Block ice (cont'd.)

  • Blocks are slotted lengthwise and installed onto a steel cable equipped with cruciforms every six feet andloweredin to fill the basket
  • A plate is installed at the top of the basket to support postulated design loads during accident conditions

+

17

Benefits of Using Block ice

  • initialloaded weights consistently higher with block ice than with flake ice, resulting in longer basket life cycles
  • Sublimation rates essentially the same as flake ice
  • Replenishment time and cost per basket sign!ficantly lower

. The block ice process minimizes ice fallout during the unloading and reloading processes.

35 Current Status

  • The use of up to 15% (292 baskets) block ice per unit has been evaluated
  • Westinghouse WCAP-14624 was issued to evaluate the use of revised block ice basket parts and addressed basket loads with block ice 36 18

______________-_.__-__________________--_____-_____________j

Current Status (cont'd.)

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  • Catawba has implemented small scale use of block ice.
  • The small scale implementation was under the station modification process and was evaluated under 10 CFR 50.59.
  • No unreviewed safety question was revealed for small scale implementation

= CNS Unit 1 has 60 baskets and CNS Unit 2 has 5 baskets containing block ice 37 Future Plans 1

  • Block ice is planned to be installed at the rate of 100 to 200 baskets per outage. I
  • Current planned maximum implementation is 35%

to 50% of the ice bed as determined by basket life cycle length and cost benefit.

38 19

+

Block ice Testing Objectives l

= Compare the thermal performance (steam-ice heat transfer) of " flake" Ice and " block" Ice under loss of coolant accident (LOCA) blowdown i

conditions.

Benchmark the GOTHIC containment response code steam-ice heat transfer for block ice and flake ice during blowdown.

39 Block ice Testing Facility (Wyle Labs)

  • Test Section

- One ice basket is sufficient to study steam ice heat transfer for LOCA blowdown conditions

- Full diameter (12")

- Half height (24')

- Basket contained in pipe (90 in2 flow area) 40 20 i

= . . .

Block Ice Testing Facility (cont'd.)

  • Steam Supply

- Desired mass flow rate vs. time achieved by a fast-acting control valve

- Steam passes through flow straighteners to the test section

  • Exhaust Section

- Sized to limit peak pressure

- Steam which penetrates the ice bed will condense and collect here (amount measured after test) i 41 Block ice Testing Facility (cont'd.)

  • Instrumentation

- Pressure, temperature and flow rate upstream of supply control valve

- Control valve position

- Pressure and temperature just upstream of fiow straightener

- Weight of ice basket and ice

- Axial fluid temperature variation within test section

- Pressure and temperature above the ice basket

- Pressure and temperature in the exhaust volume

- Weight of the drain tank

- Pressure and temperature in the drain tank 42 21

e d Block ice Test Series

  • High Flow tests: peak flow to bound design basis LOCA flow peak per basket
  • Low Flow tests: lower flow peak for additional benchmarking

. Flake ice; small, medium, and large diameter block ice e

i Block ice Test Series (cont'd.)

= 2 flow rates X 4 !ce types = 8 tests

  • Current target is for testing to begin in July,1998

. Prc,ect, including final test report, to be completed in 1998

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Licensing Requirements

  • The block ice testing program results will be evaluated to determine effect on licensing basis analyses.

- Larne scale imniementation may be possible

' .0CFR 5s.59.

  • The change will be evaluated using a 10 CFR 50.59 Safety Evaluation.

45 Licensing Requirements (cont'd.)

1

  • If the 50.59 Safety Evaluation of large scale implementation identifies a USO then the scope of a license amendment under 10 CFR 50.90 will be determined

. Any Technical Specification amendments required will be made as per 10 CFR 50.90

. DPC-NE-3004 topical report will be revised as necessary to include computer code revisions or modeling changes.

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ASYMMETRIC ICE DISTRIBUTION 47 l Ice Bay Sublimation Rates Areas C :M er nnn n OdhdNkh unwasssa 48 24

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Minimum basket weight n p p '9MM OOOf")4 M

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the same for allice g 7 4 M K %;; ' baskets and based on pM M Md j .,

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  • - " a[e,[ ~a of 144 basket weights 49 Asymmetric Ice Weight Distribution O
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Asymmetric Ice Distribution Benefits i

  • Would allow more effective use of outage resources by taking advantage of excess ice i inventory available in low sublimation areas 51 GOTHIC Model Changes
  • Refinement of detail in Ice Condenser region to capture rows of baskets with lower initial ice masses i

l 52 1

26

__________________________________j

+

Short Term Analysis Characteristics About 20-40% of initial ice inventory melts during blowdown phase.

  • This ice melt is heavily concentrated in the lower half of the ice bed.

= No steam passes through the ice condenser into upper containment.

  • Results of analysis will not be significantly l different with lower ice mass in some baskets.

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53 Licensing Requirements

  • DPC-NE-3004-PA revised, submitted for NRC review.

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. Technical Specification amendment under 10 CFR 50.90 54 27

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Conclusions

  • Any additional questions
  • Would future updates be beneficial to ONRR staff 55 28