ML14300A545

10/30/2014, Meeting Slide with NRC Regarding GL 2004-02 Close Out for Three Mile Island, Unit 1

ML14300A545
Person / Time
Site:	Three Mile Island
Issue date:	10/30/2014
From:	Exelon Nuclear Generation Corp
To:	Plant Licensing Branch 1
Lamb J L
References
GL-04-002
Download: ML14300A545 (10)

Text

GL 2004-02 C LOSE O UT FOR T HREE M ILE I SLAND U NIT 1 MEETINGWITH NRC OCTOBER 30, 2014 GL 2004 GL 2004--02 Close Out for TMI 02 Close Out for TMI Purpose of Meeting:

• Communicate current TMI plan for closure of GL 2004 02 2004-02 .*Provide updated schedule of activities related to closureofGL2004

-02forTMI.closure of GL 2004 02 for TMI. *Identify any areas of concern that can be addressed durin g the TMI strainer testin g p ro g ram.ggpg*Identify areas where additional discussion/review may be required to ensure successful closure of GL 200402fThMilIldUi1 2004-02 f or Th ree Mil e I s l an d U n i t 1.2 GL 2004 GL 2004--02 Close Out for TMI 02 Close Out for TMIIn July, 2012, NRC provided three options for closure of GSI-191*: Option1:Compliancebasedonapprovedmodels Option 1: Compliance based on approved models oPlants must meet "clean plant criteria" or oHave sufficiently low strainer bypass and oMeetthe15gramperfuelassemblylimit o Meet the 15 gram per fuel assembly limitOption 2: Mitigative measures and alternative methods2a -Deterministic Resolution Path2b -Full Risk-Informed Resolution Path O ption 3: Different re g ulator y treatments for strainer pgyand in-vessel effects oUse deterministic approach for strainer and a risk-informed approach to in-vessel.

oThis option only conceptually defined in 2012 and is still under development.

• SECY-12-0093 3

GL 2004 GL 2004--02 Close Out for TMI 02 Close Out for TMITMI selected Option 2a -complete additional modifications and pursue refinements to evaluation methods and acceptance criteria.*{TMIpreioslapplieda7DZOIforNkoninslationThepdated

{TMI pre v io u sl y applied a 7D ZOI for N u kon ins u lation. The u pdated analyses and testing will apply the 17D ZOI.}TMIcommittedto:

TMI committed to:*Replace the NUKON insulation currently installed on the pressurizer with Metallic Reflective Insulation (MRI) in T1R21 (Fall2015).(Fall 2015). *Complete strainer head loss testing based on the reduced strainer debris load by 12/31/15

• Re-evaluatestrainerbypassby7/31/16 Re evaluate strainer bypass by 7/31/16*Submit a final updated supplemental response to support closure of GL 2004-02 for TMI Unit 1 by 6/1/17.

• TMILetter(TMI 12148)toUSNRCdatedMay162013 TMI Letter (TMI-12-148) to USNRC dated May 16 , 2013.4 GL 2004 GL 2004--02 Close Out for TMI 02 Close Out for TMICurrent TMI plan/schedule

• Conduct strainer head loss and bypass testing @ Alden Research Laboratory (Holden, MA) in 2014*Based on strainer head loss test results, replace Nukon blanketinsulationonthepressurizerwithMRIinfall blanket insulation on the pressurizer with MRI in fall 2015 refueling outage (T1R21).*Submit final u pdated su pp lemental res ponse to the ppppNRC in 2016 pending completion of the PWROG efforts.5 GL 2004 GL 2004--02 Close Out for TMI 02 Close Out for TMI Strainer test sequence:Single Top Hat Bypass Test -November 2014This testwill evaluate the effect of debris concentration/mixture and water chemistry on strainer bypass. The results of this 'sensitivity' test will be factored into a large scale bypass test.Strainer Head Loss Testing -December 2014This test sequence will consist of a thin bed test followed by one or two full load head loss tests as required to determine the limiting debris quantity. A

test plan has been developed to evaluate several options for insulation replacementonthepressurizer.Thefinaldecisionforthescopeofinsulation replacement on the pressurizer.

The final decision for the scope of insulation replacement in T1R21 will be determined by the test results.Strainer Bypass Test -December 2014 Th e inf o rm at i o n ga in ed in t h e s in g l e top h at bypass test will be used to eoatogaedtesgetopatbypasstestbeusedtodevelop the test plan/procedures for the final bypass test.Test plans and procedures are currently being developed.

6 GL 2004 GL 2004--02 Cl ose O u t f or 02 Cl ose O u t f or TMI TMITMI pressurizer is currently insulated entirely with Nukon blanket insulation. TtifliNkith B A Two op ti ons for rep l ac i ng N u k on w ith MRI will be investigated:Option A: replace Nukon insulation abovethesupportregionwiththe Pi above the support region with the exception of the upper head.Option B: replace Nukon insulation in alllocationsexceptupperheadand P ressur i zer Support Region all locations except upper head and inside the support.The head loss test se q uence will B qdetermine which option will result in acceptable NPSH for the ECCS pumps and acceptable maximum strainer DP.

7 GL 2004 GL 2004--02 Close Out for TMI 02 Close Out for TMIEstimated debris reduction:*Option A results in approximately 46% reduction in the lfblktiltithi vo l ume o f bl an k e t i nsu l a tion on th e pressur i ze r*Option B results in approximately 81% reduction in the volume of blanket insulation on the pressurizer*If necessary, a further reduction in the volume of fiber debris at the strainer can be achieved by removing the insulation currently included in Option B as 'margin' dditithitbt an d cre diti ng th e pressur i zer suppor t as a ro b us t barrier (Option C).

{Following insulation replacement on the pressurizer, some small amounts of blanket insulation will remain on piping and components within the ZOI

.}8 GL 2004 GL 2004--02 Close Out for TMI 02 Close Out for TMITMI is continuing to follow PWROG efforts to establish the allowable debris limits for in-vessel effects.The current calculated TMI bypass of 34 grams fiber/fuel blibdbttithtfdf assem bl y i s b ase d on b ypass t es ti ng th a t was per f orme d f or another utility with an Enercon top hat strainer similar to TMI's.The TMI specific bypass test is expected to provide a lower bypass fraction.

9 GL 2004 GL 2004--02 Close Out for TMI 02 Close Out for TMI Proposed Debris Preparation Protocol for Head Loss and Final Bypass Tests*

• Debriscategorizedassmallorlargepiecesandintact

• Debris categorized as small or large pieces and intact blankets will be prepared as follows:

Insulation torn into 1"-4" pieces by hand Torninsulationwillbewettedusinggardenhosenozzle Torn insulation will be wetted using garden hose nozzleWetted debris will be mixed using a paddle to ensure even moisture penetration Additional water spray applied to ensure small pieces are separated from eachother each otherPreparation ends when it has been confirmed that the pieces readily separate within the slurry and no pieces remain floating Fidbiillbdddhkfi

• Fi ne d e b r i s w ill b e a dd e d to t h e tan k fi rst*Fiber will be prepared only as 'fines' for the single top hat bypass test.

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