ML14349A790

NRR E-mail Capture - Fwd: Ernie'S Slides

ML14349A790
Person / Time
Site:	South Texas
Issue date:	12/01/2014
From:	Harrison A South Texas
To:	Balwant Singal Plant Licensing Branch IV
References
TAC MF2400, TAC MF2401
Download: ML14349A790 (15)

Text

NRR-PMDAPEm Resource From: Harrison Albon [awharrison@STPEGS.COM]

Sent: Monday, December 01, 2014 7:00 AM To: Singal, Balwant; Lyon, Fred

Subject:

Fwd: Ernie's slides Attachments: 14SI008 Sldes.pdf; ATT00001.htm Balwant, Fred, This is the other STP presentation.

Note that we are bringing 25 copies of both presentations with us to the meeting.

Regards, Wayne Harrison 979-292-6413 Begin forwarded message:

From: "Kee, Ernie" <keeej@STPEGS.COM<mailto:keeej@STPEGS.COM>>

To: "Harrison Albon" <awharrison@STPEGS.COM<mailto:awharrison@STPEGS.COM>>

Subject:

Ernie's slides Ernie Kee 5 Pheasant Run Ln Bay City, TX 77414 YK.risk, LLC, w: http://ykriskllc.com h: http://erniestinyworld.com 979.479.2312 1

Hearing Identifier: NRR_PMDA Email Number: 1758 Mail Envelope Properties (09EDD282-012B-4012-A115-E62BE6456A9C)

Subject:

Fwd: Ernie's slides Sent Date: 12/1/2014 6:59:58 AM Received Date: 12/1/2014 7:00:07 AM From: Harrison Albon Created By: awharrison@STPEGS.COM Recipients:

"Singal, Balwant" <Balwant.Singal@nrc.gov>

Tracking Status: None "Lyon, Fred" <Fred.Lyon@nrc.gov>

Tracking Status: None Post Office: STPEGS.COM Files Size Date & Time MESSAGE 518 12/1/2014 7:00:07 AM 14SI008 Sldes.pdf 1504181 ATT00001.htm 232 Options Priority: Standard Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date:

Recipients Received:

Bounding Debris Approach:

STPNOC NRC Public Meeting 01 December - 03 December 2014 1 / 12

Summary

1. Use STPNOC 2008 validated test data to bound the LAR risk evaluation

2. Scale the test data to the current ZOI requirements

3. Show the scaled test data indicate adequate strainer performance at break sizes that have corresponding exceedance frequency in Region II or III (assume core damage frequency is the exceedance frequency at the break size)

4. Show the frequency for the largest break size below which failure in-vessel (core "ber loading) occurs is also in Region II or Region III (referred to as simulation)

5. The scaled frequencies for dierent interpolation methods are shown to be low in Region II (at the boundary of Region III) 2 / 12

Concept

1. Use results of previous strainer testing (performed in July 2008) to "nd the largest break size below which strainer failure does not occur

 Check if the break size is greater than the largest break size below which in-vessel failure occurs (i.e., 7.5 gm/FA)

 Use the smallest of the two break sizes to check CDF against NUREG 1829 exceedance frequencies

 Ensure the exceedance frequency for the smallest break size is in Region II or III of RG 1.174

2. Using the PRA, ensure the risk {CDF,CDF}, {LERF,LERF} for breaks above the smaller of the two break sizes (in-vessel or strainer) is in Region III of RG 1.174

3. If either the exceedance frequency from the initial screen fails to be in Region II OR the Probabilistic Risk Assessment is not in Region III, the results are unacceptable

4. Otherwise the evaluation of the debris risk is acceptable as long as the other requirements of RG 1.174 are met 3 / 12

4 / 12 Volume scaling - 2008 strainer test Although a 5D break would be a single-sided break (that is, half the volume of a DEGB), assume spherical volume and compute the 5

equivalent break size (nominally 17 D, see what follows) at the 2008 worst case break location that would produce the same amount of "ne debris as that which was assumed in the 2008 test.

Because the 2008 test used a dierent "nes size distribution than that used in the LAR, the more conservative "nes generation amount (ignoring the factor of two) will be used as the basis. That is, if the 2008 testing assumption was more conservative than the LAR, then use a 5D assumption, otherwise, the break needs further scaling to account for missing "nes. As shown in what follows, the 2008 "nes distribution was more conservative (although eectively equivalent) than the LAR methodology.

5 / 12

Fines distribution from dierent methods The 2008 test (AREVA, 2008) used two ZOIs, 7D and 5D. In the 7D to 5D ZOI, all the debris was assumed to be large pieces. In the 5D ZOI, 30% of 60% of the debris (that is, 18% of debris) was assumed to be "nes.

The LAR uses three shells with dierent "nes distributions as summarized in the table below. The 2008 method is more conservative (greater amount of "nes produced in the ZOI).

In order to preserve the same amount of "ber as was tested in 2008, 5D is used as the basis for scaling.

6 / 12

Volume scaling using 5D as a basis 4

V = r 3 , (1a) 3 4 4

V =  {(5)(29in)}3 =  {(17)(Xin)}3 , (1b)

3 3

{(5)(29in)}3 = {(17)(X )}3 , (1c)

 

{(5)(29in)} = {(17)(X )}3 ,

3 3 3 (1d)

(5)(29in) = (17)(X ), (1e) 5 X = (29in), (1f) 17 X = 8.53in. (1g) 7 / 12

5D ZOI scaling produces the same amount of "nes 8 / 12

Looking up the exceedance frequency The initial CDF used is for the exceedance frequency associated with the equivalent break size (8.53 in) determined for the 5D ZOI.

The values from NUREG-1829 (repeated in here below) are used.

Table: NUREG-1829 (Tregoning et al., 2008, Table 7.19) for the mean, median, 5th percentile, and 95th percentile exceedance frequency values for current-day estimates NUREG-1829 Values Category Break Size 5th Median Mean 95th 1

cat1 2 6.80E-05 6.30E-04 1.90E-03 7.10E-03 cat2 1 58 5.00E-06 8.90E-05 4.20E-04 1.60E-03 cat3 3 2.10E-07 3.40E-06 1.60E-05 6.10E-05 cat4 7 1.40E-08 3.10E-07 1.60E-06 6.10E-06 cat5 14 4.10E-10 1.20E-08 2.00E-07 5.80E-07 cat6 31 3.50E-11 1.20E-09 2.90E-08 8.10E-08 9 / 12

Looking up the exceedance frequency Table: The CDF obtained if failures above the Break Size are assumed to go to failure and those below are success. Break Size data comes from simulation and test and the frequency data (CDF) from (Tregoning et al., 2008, Table 1, page xxi). Note that the in-vessel results, 7.34 inches (STPNOC, 2014, Attachment 1, page 37, APLAB RAI 2b), are included since both the strainer and core need to be considered.

Source Break Size Interpolation Method CDF Test 8.53 Log-Linear 1.02E-06 Test 8.53 Linear-linear 1.29E-06 Simulation 7.34 Log-Linear 1.45E-06 Simulation 7.34 Linear-linear 1.53E-06 10 / 12

Looking up the exceedance frequency Figure: Data for 7 inch and 14 inch equivalent break sizes from (Tregoning et al., 2008, Table 1, page xxi) (diamonds) shown with log-linear interpolated data (squares) and linear data interpolation (triangles) for the equivalent simulated and test break sizes 7.34 inches and 8.53 inches.

11 / 12

References AREVA (2008, August). South Texas Project Test Report for ECCS Strainer Testing. AREVA NP Document 66-9088089-000, AREVA NP, 7207 IBM Drive, Charlotte, NC 28262.

STPNOC (2014, July). South Texas Project Units 1&2 Docket Nos. STN 50-498, STN 50-499 Third Set of Responses to April, 2014, Requests for Additional Information Regarding STP Risk-Informed GSI-191 Licensing Application (TAC NOs MF2400 and MF2401). STP LTR NOC-AE-14003105/STI32407300, ML14202A045, NRC Public Document Room.

Tregoning, R., L. Abramson, and P. Scott (2008, April). Estimating Loss-of-Coolant Accident (LOCA) Frequencies Through the Elicitation Process. NUREG/CR 1829, Nuclear Regulatory Commission, Washington, DC.

12 / 12

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