Text

Additional Information and Commitments Related to Proposed License Change for Cycle 14 Risk-Informed Operation, Diskette with ANO-2 MAAP Data Attached
	ML003731830
Person / Time
Site:	Arkansas Nuclear
Issue date:	06/30/2000
From:	Anderson C; Entergy Operations
To:	; NRC/OCIO/IMD/RMB
References
	-RFPFR, 2CAN060018, TAC MA8418
	Download: ML003731830 (67)
	v • d • e

Enery1448 Entergy Operations, Inc.

3 RLsselvi',,e, A 728-1 Te! 50'858 4888 Craig Anderson Vice President Operat -ns &NO June 30, 2000 2CAN060018 U. S. Nuclear Regulatory Commission Document Control Desk Mail Station OP 1-17 Washington, DC 20555

Subject:

Arkansas Nuclear One - Unit 2 Docket No. 50-368 License No. NPF-6 Additional Information and Commitments Related to Proposed License Change For Cycle 14 Risk-Informed Operation (TAC NO. MA8418)

Gentlemen:

On March 9, 2000 (2CAN030003), Entergy Operations submitted a proposed license change to allow risk-informed operation for the remainder of the 14th operational cycle for Arkansas Nuclear One, Unit 2 (ANO-2). Supplemental information in support of the proposed change was submitted on April 11, 2000 (2CAN040005) April 28, 2000 (2CAN040006),

May 30, 2000 (2CAN05001 1), and June 20, 2000 (2CAN060015). Based on several interactions with the Staff concerning the proposed change, the following supplemental information is provided as attachments to this letter:

1. Framatome burst equation and leakage calculation for tube 8-134

2. Review of 2P99 DSIs and thermal hydraulics of depressurization procedure

3. K factors for ECCS vent

4. RCS depressurization evaluation

5. HRA modeling process

6. Loop seal discussion

7. Comparison of actual and predicted burst and ligament tearing pressures In conversation with the NRC staff the week of June 26, 2000, Entergy Operations provided conservative estimates for primary-to-secondary leakage at the end of cycle 14 due to the peak pressures associated with the design basis main steam line break (MSLB) accident.

Leakage for eggcrate flaws at MSLB conditions (2500 psi), based on a 95/95 level of confidence, was calculated to be slightly less than 0.05 gpm per steam generator. The eggcrate flaws in combination with predicted leakage from other sources (other damage Al

U. S. NRC June 30, 2000 2CAN060018 Page 2 mechanisms, sleeved and plugged tubes) was significantly less than the 1 gpm assumed in the accident analysis.

The importance of the primary-to-secondary leak rate value is its input into the offsite dose calculations for the MSLB accident. If a 10 GPM leakage value were assumed with all other variables held constant, an offsite dose in excess of the NRC's acceptance criteria would result. While Entergy Operations does not believe primary-to-secondary leakage will be of this magnitude, actions can be taken to offset the dose consequences assuming leakage of this quantity. Entergy Operations has already committed in our correspondence dated June 23, 2000, to administratively control steady state primary coolant activity to 20% of the ANO-2 Technical Specification 3.4.8 limits. While these controls will significantly limit the offsite dose associated with the event generated iodine spike, they do not address the dose calculations associated with the pre-existing iodine spike. To address this latter case and to assure that the offsite dose remains consistent with current accident analysis predictions, Entergy Operations commits to the following administrative limits for the remainder of cycle 14:

Technical Specification 3.4.8 Entergy commits to limit the specific activity of the primary coolant to:

a. < 0.2 jiCi / gram DOSE EQUIVALENT 1-13 1, and

b. < 20 /F p.Ci / gram

c. The dose equivalent 1-131 limit of Technical Specification Figure 3.4.1 shall be

< 6 ptCi / gram at all power levels Technical Specification 3.7.1.4 Entergy commits to limit the specific activity of the secondary coolant system to:

< 0.02 RCi / gram DOSE EQUIVALENT 1-131 These controls will be implemented on or before July 7, 2000. If plant conditions exceed these limits, the corresponding technical specification actions will be taken.

The effectiveness of these controls was calculated for the limiting MSLB offsite dose (2 hour2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months exclusion area boundary thyroid dose). The calculation assumed the RCS and secondary radioisotope activity level to be at the administrative limits specified above and a 10 GPM primary-to-secondary leak under MSLB conditions. This assessment showed that the MSLB two hour exclusion area boundary thyroid dose remains at about 10 rem, consistent with the current analyses of record. This predicted dose continues to provide substantial margin to the Standard Review Plan acceptance criteria of 30 rem for this event. Current RCS and secondary activity levels are far below the assessed limits and are not expected to increase

U. S. NRC June 30, 2000 2CAN060018 Page 3 over the remainder of the cycle. Thus, the administrative controls proposed will assure offsite dose consequences will not be impacted, even if considerably higher primary-to secondary leakage than Entergy Operations predicts (up to 10 GPM) were to occur during a MSLB accident.

Should you have questions concerning the information provided, please contact me.

Very truly yours, CGA/jjd attachments cc: Mr. Ellis W. Merschoff Regional Administrator U. S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011-8064 NRC Senior Resident Inspector Arkansas Nuclear One P.O. Box 310 London, AR 72847 Mr. Thomas W. Alexion NRR Project Manager Region IV/ANO-2 U. S. Nuclear Regulatory Commission NRR Mail Stop 04-D-03 One White Flint North 11555 Rockville Pike Rockville, MD 20852

Attachment to 2CAN060018 Attachment 1 Framatome Burst Equation and Leakage Calculation for Tube 8-134

Framatome Burst Equations Used to Estimate Burst for the ANO2 Tubinf The following is the burst equation developed by Framatome that is referenced in the EPRI "Steam Generator Degradation Specific Management Flaw Handbook":

P=B4*0.58(G 7 +au,)t/R, [1.104-(L/L+2t)h]

where 4 = 1.0 for OD cracking (c- + or.) = Yield + Ultimate Material Stress (125,900 psi) t = Tube wall thickness (0.048 inch)

R,= Inside radius (0.327 inch)

L = Structural Length h = Ratio of Degradation Depth to Tube Thickness The variable value of 1.104 represents the average or "best fit" for calculating burst. A value of 0.988 variable, based on using a 95% confidence level was used for the condition monitoring analysis. The best estimate value is 1.014 (90% confidence), which was used in the 2P99 deterministic analysis. This is the explanation why the 3DP lines are different on the two graphs.

Parameter 2CAN129911 2CAN020005 Cond. Monitoring 2P99 Deterministic Burst Variable 0.988 1.014 Length 1.32 0.98 Material Properties 130,000 125,900 Growth Rate 28% TW/ EFPY 15 % TW/ EFPY BOC Average Depth 51.4 % 56.6 %

The condition monitoring report used conservative values while the deterministic used values specified in the EPRI Tube Integrity Assessment Guidelines.

PROFILER: Axial Crack Critical Profile Calculator INPUT FILE: D:\OPCON2000\Profilerkano2_2p99_8_134.in ANALYSIS TITLE: ANO-2 2P99 TUBE R8C134-01H Analysis Type 3 FULLY PROBABILISTIC ANALYSIS Tube Outside Diameter, D, 0.75 in Tube Wall Thickness, t 0.048 in Yield + Ultimate Strength, cl + cyu 134000 psi Std. Dev. on cy + au 5270 psi Lower Limit on y + Gu (psi) psi 123000 Upper Limit on Gy + a (psi) psi 155000 Measurement Error Slope 1

Measurement Error Offset 0.1 Crack Profile Index 0 No. of Profile Data Points 23 No. of Profile Segments 22 No. of Divisions per Segment 10 CRACK PROFILE DATA Axial Position Depth (in) (% TW) 0 0 0.01 85 0.04 100 0.06 98.5 0.09 96 0.11 96 0.14 94.5 0.16 94.5 0.19 94.5 0.21 95 0.24 93.5 0.26 94.5 0.29 94 0.31 92.5 0.34 93.5 0.36 94 0.39 94 0.41 94 0.44 94 0.46 93 0.49 82 0.51 67.5 0.53 0 Crack Profile Length, L 0.53 in OPCON 2000 (PROFILER)

Rev 0 (Januay 1. 2000)

INPUT

LEAKER: Leak Rate Calculator INPUT FILE: leaker.in ANALYSIS TITLE: Test Case 222 Crack Orientation AXIAL Analysis Type 1

LEAK RATE FOR A GIVEN LENGTH Plant Condition 2 STEAM LINE BREAK Tube Outside Diameter, D, 0.75 in Tube Wall Thickness, t 0.048 in Modulus of Elasticity, E 28700000 psi Yield + Ultimate Strength, cy + au 134000 psi Tube Differential Pressure, *5p 2500 psi No. of Calculation Points I CALCULATED CRITICAL STRUCTURAL LIMITS CRITICAL AXIAL LENGTH = 0.9094 IN.

LEAK RATE RESULTS - AXIAL CRACK (Q VS L)

TW CRACK LENGTH LEAK RATE, Q (INCHES) (GPM @ RT) 0.25 0.044005 OPCON 2000 (LEAKER)

Rev. 0 (January 1, 2000)

SUMMARY

History of Tube 8-134 ANO-2 SG "B" 2R13 Bobbin inspection - Reported as NDD - No RPC performed

- subsequent lookback 0.63 volts - 86% TW ID 2P99 Bobbin insp. DSI - 1.77 volts (normalized voltage for 2P99 cal standards) 99% TW

Attachment to 2CAN060018 Attachment 2 Review of 2P99 DSIs and Thermal Hydraulics of Depressurization Procedure

Response to Questions by the NRC on Leak Rate Calculations for the ANO-2 Steam Generators at MSLB Design Based Accident Conditions for the Remainder of Cvcle-14 and Evaluation of the DSI's identified in 2P99 with RPC in 2R13 Leakage at MSLB Conditions The end of cycle (EOC) flaw population was developed from the as-found conditions at 2P99. The indications identified were sized by the Westinghouse profiling technique and evaluated based on bobbin voltage and maximum depth. A probability of detection (POD) curve was used to determine which flaws would be detected and removed from service. Those remaining in service were combined with a set of flaws newly initiated to form the post 2P99 population. A probabilistic growth was used and assigned to each flaw as well as a specific material property. Typically, a sizing uncertainty is applied, but for purposes of the leak rate calculation, at the request of the NRC, this variable was removed.

This population of flaws was then used to calculate a leak rate under postulated MSLB conditions. Version 3.0 of the "Pipe Crack Evaluation Program" (PICEP), developed by EPRI, is a two-phase flow algorithm used to compute flow rates through cracks as a function of pressure differential, temperature, crack opening area and total through wall crack length. Friction effects and crack surface roughness were included in the model.

Leakage for eggcrate flaws at MSLB conditions (2500 psi) based on a 95/95 level of confidence was calculated to be slightly less than 0.05 GPM per steam generator.

Following 2R13, a probabilistic analysis was developed to evaluate all damage mechanism for a full cycle of operation. This was submitted June 2, 1999 (2CAN069901). The other damage mechanisms were evaluated in this report for full cycle operation. Adding the 0.05 GPM calculated for eggcrate flaws during the current operating interval, the total leakage at MSLB conditions would be:

0.05 (current estimate for eggcrate axial indications) + 0.11 (other mechanisms)

= 0.16 GPM Hindsight Review of RPC of 2P99 DSI's A review of all "confirmed" Distorted Support Indications (DSI) from 2P99 was accomplished using the ANO-2 Framatome Data Management System (FDMS). One of the 2P99 "confirmed" DSI locations ( tube 49-25 in the "A" SG) was inspected in 2R13 with a rotating motorized pancake coil (RPC). The indication was determined to be NDF (no detectable flaw).

2. Provide a thermal hydraulic analysis of effectiveness of the depressurization procedure. This calculation should assess the probability (as a function of flaw stress magnification factor) of a tube in either steam generator being the first creep failure of the RCS pressure boundary, given that the depressurization occurs with the delay time provided in response to question

6. Stress magnification factors between 1.0 and 7.5 should be assessed in increments of 0.5 (to facilitate graphical comparison to MAAP results to Staff RELAP audit analysis, the staff requests that the MAAP data plot output files (e.g., PLOTFIL 31) be provided for each MAAP analysis in an electronic format. The fixed format (e.g., IPLTI=2) is preferred.

This question can be divided into three parts:

(1) Provide a thermal hydraulic analysis of effectiveness of the depressurization procedure.

(2) Assess the probability (as a function of flaw stress magnification factor) of a tube in either steam generator being the first creep failure of the RCS pressure boundary, given that the depressurization occurs with the delay time provided in response to question 6. Stress magnification factors between 1.0 and 7.5 should be assessed in increments of 0.5.

(3) To facilitate graphical comparison to MAAP results to Staff RELAP audit analysis, the staff requests that the MAAP data plot output files (e.g.,

PLOTFEL 31) be provided for each MAAP analysis in an electronic format.

The fixed format (e.g., IPLTI=2) is preferred.

The following is in response to the first part of the question. Aside from restoring feedwater, the most effective means to mitigate high/dry sequences that pose a risk of temperature induced steam generator tube rupture is to depressurize the RCS. To this end, modifications have been made to ANO-2 hardware and procedures to increase the likelihood of such an action and to minimize the delay in initiating depressurization. To quantify the benefits of this strategy, MAAP and PROBFAJL calculations were run for the accident sequences considered in previous ANO work. For each sequence, best-estimate thermal hydraulic parameters were modeled and the operators were assumed to initiate depressurization at 15 minutes (consistent with our response to Question 6 as documented in our letter to the Nuclear Regulatory, 2CAN060012), 30 minutes, or 45 minutes after the occurrence of 700 K (800 F) at the top of the center ring of the core nodes in the MAAP model. Since the inner-most ring represents 12 percent of the core, this criterion corresponds well with the proposed accident management strategy which involves monitoring the hottest 12 percent of the 42 (i.e., hottest 5) core exit thermocouples (CETs).

The operator actions involve the opening of the ECCS vent valves. This system was modeled in MAAP as an equivalent pressurizer PORV. This modeling utilized an Entergy-calculated K/d 4 value calculated for the entire system from the pressurizer to the quench tank of 0.0815 in4. Using the MAAP GFLOW Page 1

compressible flow model, this was calculated to result in a flow rate of 55 kg/sec under saturated conditions at 17 MIPa, and this value was used to size the relief valve. It should be noted that this represents a flow rate approximately double that expected of a typical PORV found in a Westinghouse PWR. For expediency, all MAAP calculations were terminated 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months after the initiation of depressurization or at vessel failure, whichever came first.

The probability of a SG tube failure prior to hot leg failure for the "high/dry/low" and the "high/dry/high" sequences are shown in Table 1. These results are calculated by PROBFAIL. The results conservatively do not credit surge line rupture. Results are provided for End of Period (EOP) tube conditions assuming 93 defects. The EOP condition is limiting, since it represents the condition of the SGs just prior to 2R14 without a SG inspection between 2P99 and 2R14.

Analyses were performed using both the best-estimate "leak-before-break (LBB)"

model in PROBFAIL (this credits the ANL rupture mode model from NUREG/CR-6575) and a model in which "leak-before-break" is not credited. As shown, depressurization prior to 30 minutes provides a substantial benefit in all cases.

The following is in response to the second part of the NRC question. To facilitate a comparison of these results to those obtained by the NRC, an additional set of PROBFAIL calculations were run to calculate the conditional probability of rupture for a set of defects with a specific range of mp' s. These results are shown in Tables 2 and 3. The ANL "leak-before-break" model was not credited in these calculations, so the values shown represent the probability of ligament failure prior to hot leg rupture, irrespective of whether that would lead to tube rupture. Note that the maximum calculated failure probability for any given defect is 0.5, since each defect is assumed in the model to have a 50 percent chance of seeing the cold return flow. The weightings used for the other temperatures in the model are 10 percent for the peak temperature present in the outward flow and 40 percent for the average outward flow temperature. These are the same values used in previous ANO-2 calculations and are believed to be a conservative characterization of the Westinghouse 1/7 scale test data.

Finally, Table 3 indicates that the probability of tube rupture in the high/dry/high sequences with depressurization is negligible when mp is less than or equal to 7.5.

As shown in Table 1, failures are possible in this sequence at ANO-2 EOP conditions with depressurization at 30 minutes when leak before break is not credited. Such failures are caused by the presence at EOP of a small probability of a defect with a very large mp (i.e., larger than 7.5).

It should be noted that the results presented in Tables 2 and 3 are provided to allow a comparison of the MAAP/PROBFAIL results with those generated by the NRC. It should be noted that these results , like those presented in Table 1, are not sufficient to assess the risk benefits of a ANO-2 SG inspection/repair outage Page 2

between 2P99 and 2R14. Additional information is required to assess this risk.

This information includes the probability that a defect with given mp exists in the SGs, the likelihood that ligament failure will "fishmouth", the frequency of a severe accident, the thermal-hydraulic conditions associated with each accident (e.g.,

high/dry/low), the status of the plant equipment required to accomplish RCS depressurization, and the probability of operator actions to perform the depressurization.

The following is in response to the third part of the NRC question. The NRC has requested certain MAAP plot files be written using the IPLTI=2 option.

Precisely what variables are of interest were not specified, so the standard set of plot files used in the other ANO-2 MAAP runs was generated. Only those plot files which were considered of interest to the NRC, i.e., those related to the RCS boundary or SG tube integrity are provided for the High/Dry/Low and High/Dry/High accident scenarios with no operator action and with operator action to depressurize the RCS at 15 minutes, at 30 minutes, or at 45 minutes after the 800 F CET cue is reached. Table 4, below, provides a list of these plot files and their descriptions. Plot file 31, as specifically requested, is included in this list of files. Other files or related information is available, if they are desired. For convenience, since the files are large, these files have been compressed into the single zipped file, A2MAAPPs.zip.

To aid in the interpretation of these files, a short glossary is included below that explains a few key variables of interest. The meaning of other entries in the plot files can often be discerned using the explanations provided in the sample parameter file provided in Volume 1 of the MAAP Users Manual.

The variables are stored in the order dictated by the header at the top of each file.

Thus, if "ZWV" is the seventh variable listed in the header, it is the seventh numerical entry. Given the IPLTI=2 option, the numerical entries are provided with a fixed format, 4 entries to a line. Time is always the first entry in each file.

The total number of variables contained in the file is given by the absolute value of the number written on the first line of the file. Note that all variables are being supplied in SI units (m-kg-sec).

Plot File 31:

PPS RCS pressure PBS Pressure in "B" S/G PUS Pressure in "U" S/G ZWBS Collapsed water level in B S/G ZWUS Collapsed water level in U S/G ZWPZ pressurizer water level above bottom of unit ZWV two phase water level, relative to bottom of RPV head TCRHOT temperature of hottest core node MH2CR1 hydrogen mass generated in core Page 3

WSGBL steam generator recirculatory flow rate in B loop WHLBL hot leg counter-current flow rate in B loop MCMTPS total debris mass in lower plenum of RPV Plot file 34:

TSRN(1,1) Temperature of first surge line node W(3) Unidirectional gas flow rate leaving B hot leg for SG inlet plenum W(9) Unidirectional gas flow rate leaving U hot leg for SG inlet plenum Plot file 85:

FEXTRA(321) Temperature of first node (just above tubesheet) in tubes receiving gas having the peak temperature from B S/G inlet plenum FEXTRA(33 1) Temperature of first node in tubes receiving gas having the peak temperature from U S/G inlet plenum TBHTO(1,1) Temperature of first node in tubes receiving average temperature gas from B S/G inlet plenum TUHTO(1,1) Temperature of first node in tubes receiving average temperature gas from U S/G inlet plenum TBH(2,1) Temperature of innermost node in top half of the B loop hot leg*

TBH(2,2) Temperature of middle node in top half of the B loop hot leg TBH(2,3) Temperature of outer most node in top half of the B loop hot leg TUH(2,1) Temperature of innermost node in top half of the U loop hot leg*

TUH(2,2) Temperature of middle node in top half of the U loop hot leg TUH(2,3) Temperature of outer most node in top half of the U loop hot leg TGUP Gas temperature in upper plenum of RPV

HOTLEG code employs a finer nodalization of the hot leg than is used in MAAP The hot leg nodal temperatures provided in the plot file 85 can be used to calculate the volume-weighted hot leg temperature via the following algorithm:

Volume-weighted B loop hot leg temperature =

0.25*TBH(2,1)+0.5*TBH(2,2)+0.25*TBH(2,3) and Volume-weighted U loop hot leg temperature Page 4

0.25*TUH(2,1)+0.5*TUH(2,2)+0.25*TUH(2,3).

However, the volume weighted hot leg temperature calculated in the HOTLEG code is used to calculate the time of hot leg rupture in PROBFAIL. HOTLEG utilizes the upper plenum temperatures and flow rates from MAAP to calculate the temperature at the RPV nozzle/hot leg interface using a more detailed model than is contained in MAAP. The time of rupture calculated using HOTLEG temperatures is typically very close to that which would be calculated using the temperatures directly from MAAP.

Table 1. Results for Base Case Sequences at EOP Sequence Operator SG Tube SG Tube action Rupture Ligament timing Prob. Failure (minutes) (LBB) Prob.

(no-LBB)

High/dry/low 15 9.E-3 0.028

("base") 30 0.027 0.10 45 0.62 0.82 none 0.65 0.84 High/dry/high 15 no rupture no rupture

("pbase") 30 no rupture 0.032 45 no rupture 0.08 none 1.5E-4 0.10 Page 5

Table 2. Probability of SG Tube Ligament Failure prior to Hot Leg Failure for High/Dry/Low Accident Condition Conditional failure probability of ligament 12 MP Depressurize 15 Depressurize 30 No operator action minutes after cue minutes after cue 1.0 negl. negl. 4.E-5 1.5 negl. negl. .027 2.0 negl. negl. .099 2.5 negl. negl. .22 3.0 negl. 4.4E-3 .40 3.5 negl. .026 .48 4.0 negl. .058 0.50 4.5 negl. 0.12 0.50 5.0 1.1E-6 0.20 0.50 5.5 2.1E-5 0.30 0.50 6.0 2.4E-4 0.38 0.50 6.5 1.9E-3 0.44 0.50 7.0 6.6E-3 0.47 0.50 7.5 .016 0.49 0.50 1 Note that the maximum calculated failure probability is 0.5, since each defect is assumed to have a 50 percent chance of seeing the cold return flow. The weightings used for the other temperatures in the model are 10 percent (peak temperature present in the outward flow) and 40 percent (average outward flow temperature).

2. Leak-before-break (ANL rupture mode model) is not credited in any these calculations.

Page 6

Table 3. Probability of SG Tube Ligament Failure prior to Hot Leg Failure for High/Dry/High Accident Condition 1 2 Conditional failure probability of ligament '

MP Depressurize 15 Depressurize 30 No operator action minutes after cue2 minutes after cue 2 1.0 negl. negl. negl.

1.5 negl. neg1. neg1.

2.0 negl. neg1. negl.

2.5 negl. negl. 9E-6 3.0 negl. negl. 4.8E-4 3.5 neg1. negl. 5.7E-3 4.0 negl. negl. .023 4.5 negl. neg1. .049 5.0 negl. negl. .076 5.5 negl. negl. .10 6.0 negl. negl. 0.14 6.5 negl. negl. 0.19 7.0 negl. negl. 0.26 7.5 negl. negl. 0.33 1 The maximum calculated failure probability is 0.5, since each defect is assumed to have a 50 percent chance of seeing the cold return flow. The weightings used for the other temperatures in the model are 10 percent (peak temperature present in the outward flow) and 40 percent (average outward flow temperature).

2. Leak-before-break (ANL rupture mode model) is not credited in any these calculations.

Page 7

T,)hl* A "Tdt%A J a... UN i~L IUL rCa rou deinc t-1&,J A2.

A.JV -j-rr.LIp File Name RCS Pressure/SG Time Delay for Plot File Type Level/SG Pressure Operator RCS Depressurization (minutes)

Base op.d31 I-igh/Dry/Low 15 31 Base op.d34 34 Base op.d85 85 Base_op.d87 87 Base op 1.d31 30 31 Base opl.d34 34 Base opl.d85 85 Base opl.d87 87 Base op3.d31 45 31 Base op3.d34 34 Base op3.d85 85 Base op3.d87 87 Basel.d31 No operator action 31 Basel.d34 34 Basel .d85 85 Basel.d87 87 Pbase op.d31 I-Iigh/Dry/High 15 31 Pbase op.d34 34 Pbase op.d35 85 Pbase op.d87 87 Pbase opl.d31 30 31 Pbase opl.d34 34 Pbase opl.d85 85 Pbase opl.d87 87 Pbase op3.d31 45 31 Pbase op3.d34 34 Pbase op3.d85 85 Pbase op3.d87 87 Pbasel.d31 No operator action 31 Pbasel .d34 34 Pbasel.d85 85 Pbasel.d87 87 Page 8

Attachment to 2CAN060018 Attachment 3 K Factors for ECCS Vent

[Pa-e I of I LLOYD, MICHAEL From: RICHARDSON, JOHN W Sent: Friday, June 16, 2000 7:48 AM To: LLOYD, MICHAEL

Subject:

RE: K factors for ECCS vent Mike, My references are M2230, sht 2 rev. 34, Iso's 2BCA-14-1 sht 1 rev. 15, 2FCC-1-1 sht 1 rev. 15, 2FCCa1-1 sht 2 rev. 2, 2FCC-2-1 rev. 12 and 2FCC-2-2 rev 8.

John

- Original Message ----

From: LLOYD, MICHAEL Sent: Thursday, June 15, 2000 10:03 PM To: RICHARDSON, JOHN W Cc: COX, ALAN B; FOUTS, DANIEL W

Subject:

RE: K factors for ECCS vent John.

Thanks for the quick response. Marc said that he received the info and is inputting this into his analysis.

We will need your supporting documents so that we can put them into our calculation supporting the ANO-2 SG Tube Rupture Risk Assessment.

Mike Lloyd

Original Message ----

From: RICHARDSON, JOHN W Sent: Thursday, June 15, 2000 2:40 PM To: 'Mark Kenton' Cc: LLOYD. MICHAEL

Subject:

K factors for ECCS vent Mark, From the pressurizer to the quench tank, there are the following lengths of pipe and fittings:

6" sch 40 - 53.01' pipe, 7- 90 degree ells, 1 45 degree ell 6" sch 120 - 4.74' pipe, 2 branch tees, 1 6" x 4" reducer 4" sch 120 - no pipe, 1 gate valve Cv = 735, 1 4"x4"x3" branch tee 3" sch 160 - 12.0' pipe, 3 elbows, 1 gate valve Cv = 460 3" sch 40 - 10.23' pipe, 2 elbows, 1 6"x6"x3" branch tee 10" sch 20 - 61.56' pipe, 10 elbows I make the total K/d^4 = .0815 John Richardson 6/28/2000

Page 1 of 2 2BCA-14-1 Pressurizer K= K/d4 =

6" lengths (in) 4.74 ft 6" sch 120 pipe d=5.501" 0.155181 43.91 pipe sch 120 ss 2 branch tees 1.8 tee (branch) 6" x 4" reducer K=.404 0.404 13 pipe sch 120 ss tee (branch) Total 2.359 0.002576 reducer (6" to 4")

56.91 Total Pipe Length 4" lengths (in) gate valve Gate valve Cv =730.284 3.624" d 0.284 reducing tee (branch) (4"X4"X3") 4" x 3" branch tee, K=1.32 1.32 1.604 0.009299 3" lengths (in) 15.625 pipe sch 160 ss 12 ft 3" sch 160 pipe d=2.624" 0.987805 elbow (90) 3 elbows 0.756 38.625 pipe sch 160 ss Gate valve Cv =460.200 0.2 elbow (90) 1.944 0.041001 65.5 pipe sch 160 ss elbow (90) 24.25 pipe sch 160 ss 144 Total Pipe Length 1 0.23 ft 3" sch 40 pipe d=3.068" 0.720176 2FCC-2-2 2 elbows 0.504 3" lengths (in) 4" x 3" branch tee, K=1.06 1.06 7.5 pipe sch 40 ss 2.284 0.025781 elbow (90) 71.5 pipe sch 40 ss elbow (90) 43.75 pipe sch 40 ss reducing tee (branch) (6"X6"X3")

122.75 Total Pipe Length 6" lengths (in) elbow (90) 5 3.01 ft 6" sch 40 pipe d = 6.065" 1.573347 49 pipe sch 40 smls ss 7 elbows 1.47 elbow (45) 1 45 deg elbow 0.294114 53.625 pipe sch 40 smls ss 3.337 0.002467 elbow (45) 102.625 Total Pipe Length 2FCC-2-1 6" lengths (in) tee (branch) 35.375 pipe sch 40 smls ss elbow (90) 194.8125 pipe sch 40 smls ss 6 1.56 ft 10" sch 20 pipe d = 10.25" 1.008993 elbow (90) 10 elbows 1.96 114.9846 pipe sch 40 smls ss 10" x 6" branch tee, K=1.13 1.13 elbow (90) 4.099 0.000371 elbow (90) 114.9846 pipe sch 40 smls ss elbow (90) 73.375 pipe sch 40 smls ss 533.5317 Total Pipe Length

Page 2 of 2 2FCC-1 -1 Total k/d 4 = 0.081496 10" lengths (in) reducing tee (10"X10"X6") (branch) 109.463 pipe sch 20 welded ss elbow (90) elbow (90) 135.463 pipe sch 20 welded ss elbow (90) 186 pipe sch 20 welded ss elbow (90) 135.463 pipe sch 20 welded ss elbow (90) elbow (90) 63.3381 pipe sch 20 welded ss elbow (90) 31 pipe sch 20 welded ss elbow (90) 78 pipe sch 20 welded ss elbow (90) elbow (90) 738.7271 Total Pipe Length K factors are from Crane T.P. 410, except for reducing tees, which are from Idelchik By:

Verified:

Attachment to 2CAN060018 Attachment 4 RCS Depressurization Evaluation

RCS Depressurization Evaluation In Entergy Operations' letter to the NRC dated March 9, 2000 (2CAN030003), a risk informed license change was proposed for Arkansas Nuclear One, Unit 2 (ANO-2), for the remainder of Cycle-14. A risk assessment supporting the request was attached to the letter. Since this submittal, Entergy Operations and the NRC Staff have engaged in extensive discussions on inputs to the risk assessment. Analysis methodology changes stemming from the discussions have been incorporated into the risk analysis. Among the most significant methodology changes is the use of stress magnification factor distributions (mp and m) for steam generator (SG) defects, rather than use of SG tube fragility curves. The results of the revised risk analysis were presented in a meeting with the NRC Staff on June 8, 2000. Similar to the previously submitted risk results, the results of the revised analysis demonstrate that the continued operation of ANO-2 to the end of cycle 14 (EOC 14) is safe.

As a result of the risk assessment performed in support of its SG operational assessment, Entergy Operations obtained several risk insights which would improve plant safety.

Among these insights are that aside from restoring feedwater, the most effective means to reducing the risk of a temperature induced steam generator tube rupture (SGTR) is (1) to maintain SG pressure high before the SG water inventory is lost, and (2) to depressurize the RCS at the onset of core damage. The SG pressure control measure was implemented via modifications to the plant emergency operating procedures. The effect of this measure was incorporated into the risk assessment submitted with 2CAN030003. At the June 8 2000, meeting, plans to implement the reactor coolant system (RCS) depressurization measure to further reduce the low risk of continued operation was described. The implementation of the RCS depressurization measure required both hardware and procedural modifications.

During accident scenarios with a loss of one emergency train (both AC and DC), the RCS cannot be depressurized using either ECCS vent or LTOP valves. The modification for RCS depressurization provides for the installation of equipment to facilitate temporary power to the ECCS vent valves. The modification provides a simple means for both ECCS vent valves to be energized from the opposite DC bus using a temporary connection to permanently mounted twist-lock plugs. Permanently mounted twist lock plugs have been connected to the load sides of 2D26 breaker 2D26-A2 and 2D27 breaker 2D27-A2.

Page 1

The plant modification allows the RCS to be depressurized via the ANO-2 ECCS vent valve paths, even if only one DC safety train is available. Since the ANO-2 ECCS vent valve path is large, opening this path will rapidly depressurize the RCS, and in so doing will provide prompt relief from a temperature induced SG tube challenge.

Plant procedural modifications have been implemented to assure that the RCS depressurization measure is timely and is accomplished quickly when needed. Since the temperature induced SGTR risk is a severe accident induced challenge which applies only when a SG's level is very low, plant procedures were revised to implement the RCS depressurization action on the following cues: (1) sustained loss of all feedwater, (2) either SG inventory very low (i.e., below 70" wide range), and (3) five or more core exit thermocouples (CETs) indicating a temperature above 8000 F. The first two cues indicate a dry (or nearly dry) SG condition; the last cue is an indication of core uncovery. A dedicated operator has been assigned the duty of trending CET temperatures following a reactor trip or loss of DC bus and to take the actions necessary to supplying power to the ECCS vent vales upon the loss of one DC bus.

The dedicated operator will report to the control room upon a reactor trip. A plant page will be made for reactor trip as a part of standard post-trip actions. The annunciator corrective action procedure also directs the dedicated operator to report to the control room upon the loss of a DC bus. Upon arrival, the dedicated operator will commence monitoring CETs and Steam Generator Wide Range Level. Once the ECCS vent initiation criterion is met, the control room staff will initiate required actions to open the ECCS vent valves. If no loss of DC has occurred the control room staff will open the ECCS vent valves from the control room. If a loss of one DC train has occurred (necessitating ECCS vent valve power cross-tie) the control room staff will open the ECCS vent valve that is energized. The dedicated operator will obtain a copy of his procedural instructions and proceed to Corridor 340 to commence his local actions. An additional copy of this procedure is stored in a locked box just outside the 2B53 room.

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The dedicated operator will open the DC bus supply breaker to the deenergized motor control center (MCC) and proceed to the 2B53 room. The dedicated operator will then open the upstream feeder breakers to both ECCS vent valves. The dedicated operator will then connect the cross-tie cable. Once the cable connectors are locked in place, the feeder breaker to the ECCS vent valve on the energized bus is closed sending DC power to the opposite train vent valve. The second ECCS vent valve is then opened from the control room commencing depressurization of the RCS. The control room will be cued to this action by communication from the dedicated operator or by observing the valve position indication lights returning. The energized ECCS vent valve de-energizes and then both valves re-energize when the dedicated operator completes his local actions.

The actions by the dedicated operator to complete the cross-tie activity has been time validated at less than 10 minutes.

Severe accident thermal hydraulic assessments indicate a temperature induced SGTR can be averted if the RCS depressurization is initiated within 30 minutes after these cues occur. Procedural modifications that assure the timely and quick implementation of the RCS depressurization action include changes to procedures 2203.012A, 2203.012G, 2202.006, 1015.001 and 1015.016, as well as the development of SDS-02. A copy of the applicable portions of these procedures is attached. In addition, operator training has been conducted on the use of the revised procedures. This training includes plant simulator training and training on the use of the ECCS vent valve cross-tie. The training study guide and qualification guide are attached.

In order to assure that the RCS action is effective, a human reliability analysis (HRA) was conducted to assess the effectiveness of plant procedural and hardware modifications associated with the RCS depressurization measure. As part of the HRA assessment, a quantitative analysis was performed to assess the likelihood of successful operator action to avert a temperature induced challenge to SG tube integrity. The results of this assessment are attached. The assessment concluded that all RCS depressurization cues are available in the vast majority of core damage scenarios. It also concluded that a 0.75 probability of successful operator RCS depressurization corresponds to about 20 minutes after the 800' F cue if both ECCS vent valves can be operated from the Control Room. If the ECCS vent valve cross-tie is required, a 0.75 probability of successful operator RCS depressurization was assessed to correspond to about 30 minutes after the 8000 F cue.

Since the probability of a temperature induced SGTR is low at 30 minutes (only about 0.027 for the High RCS pressure/Dry SG/Low (H/D/L) SG pressure core damage scenario), the action is deemed as effective in averting temperature induced SGTR challenges.

Thus, both qualitatively and quantitatively, the ECCS venting action clearly reduces the potential for creep rupture of SG tubes. Since this action further reduces the low risk of a temperature induced SGTR, it is concluded that the continued operation of ANO-2 to the end of its current cycle 14 without an additional SG inspection campaign is safe.

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Summary of Independent Human Reliability Analysis (HRA) of the RCS Depressurization Action to Mitigate the Risk of a Temperature-Induced Steam Generator Tube Rupture at ANO-2 Introduction In support of its request for the risk-informed operation of Arkansas Nuclear One, Unit 2 (ANO

2) for the remainder of its 14th operational cycle, Entergy Operations developed and implemented both hardware and procedural changes to the ANO-2 plant. The hardware changes enabled the use of the ANO-2 Emergency Core Cooling System (ECCS) vent valves to depressurize the RCS even if a single safety train of both AC and DC are lost during a core damaging event. The hardware modification both reduces the frequency of core damage and the probability of a temperature-induced SGTR. The latter was accomplished via procedural changes which direct the use of these valves at the onset of core damage concurrent with the loss of water inventory in either of the ANO-2 SGs. Mr. G. William Hannaman, an independent human reliability expert, was requested to perform both a qualitative and quantitative Human Reliability Analysis (HRA) of both plant hardware modifications and associated plant procedures which direct the RCS depressurization action as a mitigation measure to reduce temperature-induced challenges to SG tube integrity.

Mr. Hannaman's HRA review of the ANO-2 RCS depressurization mitigation measures had three main objectives:

1. Qualitatively review the impact of opening the ECCS vent valves as a defense-in-depth element that mitigates temperature-induced SGTR contributions to ANO-2's Large Early Release Frequency (LERF),

2. Observe indications and alarms available in the Control Room (CR) and associated operator actions during control room simulator exercises of accidents expected to lead to temperature induced SGTR challenges. These observations included a walk through of the local actions that are required to open ECCS vent valves.

3. Use alternate human reliability assessment (HRA) model quantifications of the Human Event Probability (HEP) for the RCS depressurization action.

The key activities accomplished during Mr. Hannaman's review were as follows:

1. Observed simulations of a licensed operating crew's response to an accident which leads to a High RCS pressure/Dry SG plant condition which could lead to a temperature-induced SGTR.

2. Performed a walk through of the local procedure SDS-02. This procedure directs the tracking of cues for performing an RCS depressurization action and provides directions on connecting either DC bus to power either ECCS vent valve motor operator.

3. Reviewed the applicability of opening the ECCS vent valves as an operator mitigation action for the ANO-2 accident scenarios with the potential for a thermal challenge to the SG tubes.

4. Subjected the procedures to an independent review by applying alternate HRA models to evaluate the human error probability (HEP) for the ECCS vent mitigation action. Provided results of time dependent HEPs.

5. Formulated opinions about actions taken by ANO-2 to minimize temperature-induced SGTR challenges during the remainder of ANO-2 Cycle 14.

Page 1 of 6

Simulator Observations The loss of 125V DC 2D01 bus concurrent with a postulated plant trip was performed on the ANO-2 plant simulator. This event causes the loss of a safety train of DC and its corresponding safety train of AC power. Additional faults included in the simulation exercise included the loss of all feedwater and loss of all RCS makeup and injection systems. The observations focused on the crew's response to cues (i.e., instrumentation and alarms) available in the control room which should lead operators to depressurize the RCS via operation of the ECCS vent valves. The loss of 2D01 concurrent with a plant trip event was selected for the exercise, because it results in a partial loss of control room indication, the loss of many alarms, and disables the operation of one of the two ECCS vent valves from the control room. Specifically, this event disables alarms which can be used as cues for ECCS vent valve operation, namely 2D01 under voltage and core exit thermocouples (CET) Temp. Hi. In addition, the ANO-2 simulator was employed to demonstrate control room indications and alarms available on the loss of 125 VDC 2D02 bus concurrent with a postulated plant trip. The loss of 2D02 has an effect similar to that of the loss of 2D01, except not as severe (i.e., not as many indications and alarms are disabled). Like the loss of 2D0 1, the loss of 2D02 disables the operation of one of the two ECCS vent valves from the control room.

The simulation verified the availability of all cues for opening ECCS vent valves under various faulted DC bus conditions and verified use of emergency procedures and functional guidelines and the use of procedure SDS-02. A dedicated control room operator, the dedicated crossover operator (DXO), implements this latter procedure.

In the simulation, utilizing the emergency procedures and SDS-02, the operations crew passed through several phases in their response to the postulated event. First, they detected the failed conditions by checking on the status of each element through the control board interface.

Detection of the precise equipment failures were communicated to the senior reactor operator (SRO) within 20 sec to 2 min 30 sec of the event. When normal responses were not available, several situation assessments were held to reevaluate the plant status. This includes explanations of local situation assessments provided to the CR crew by the simulator operator. Revised strategies for handling the event were then developed by the CR crew using the function procedures. The situation evaluations including briefings and discussion of strategies lasted from about 4 to less than 10 minutes. Based on the use of the emergency and other operating procedures, including SDS-02, the cues which indicated the need for implementing the ECCS venting procedures were available and continuously tracked. These cues would be available as long as either safety train of DC bus is available. The crew next passed into a response-planning phase, which involved defining the plan, coordinating the activities and monitoring information.

This phase took about 5 minutes. Then, the crew went into the implementing stage of their response by simulating sending the DXO to perform the cross-over operation directed in SDS-02.

It was noted that the effects of actions performed by the DXO outside of the control room could be observed in the control room. Specifically, ECCS vent valve position indications on the control panel lit when the cross-connecting operation was complete. Thus, after the cross connecting operation was completed, the re-enabled ECCS vent valve could be opened from the Page 2 of 6

control room without direct communication from the DXO in the motor control center (MCC) room location. The CR indications are expected to reduce the required implementation time by over a minute, even though follow up communication is expected.

Walkdown of the SDS-02 Procedure A guided walk through of procedure SDS-02 was performed. The walkdown began in the control room to observe how the DXO will track the RCS depressurization cues following a plant trip. It was noted that all cues could be reliably tracked on all conditions except those involving the total loss of all DC and all AC, conditions which were not identified as significant contributors to ANO-2 core damage risk.

Assuming that the cues are present, the path of the DXO was walked from the control room to other locations directed by SDS-02 for local action. The path required passage through two security card readers; however, the DXO operator's keys can be used to gain entrance to these doors, if necessary. A locked box containing a copy of SDS-02, cabling, and tools for making the connection between two busses was just outside of the second door. The DXO is trained to perform the local cross-connection operation. The MCC breakers which require manipulation were clearly marked and matched the numbers in the procedure. The documented time of less than 10 minutes for implementing the ECCS vent procedure cross-tie procedure was validated. In addition, it was noted that the MCC panels had clear backup lighting in the event of a blackout condition and that there is ample space around the MCCs for controlling and monitoring conditions.

Quantifications of the RCS Depressurization Human Event Probability (HEP)

The HRA application process employed to evaluate Human Event Probability (HEP) for the mitigating action of depressurizing the RCS is described in EPRI TR-107623. The supporting evaluations use the logic tree methodology in EPRI TR-100259 to evaluate the likelihood of cognitive errors associated with detection and situation assessment. The time dependent modeling uses the human cognitive reliability (HCR) model upgraded through the information and data gathered in the Operator Reliability Experiments and the implementation action portion is evaluated using the accident sequence evaluation program (ASEP) approach.

This HRA process provides a robust method for verifying that the new procedures are error resistive, and provides the capability of evaluating the reliability of performing the action from the time that the cue is received. The reliability of the action at a given time can be compared with the time predicted for hot gas circulation and creep rupture of a tube to verify that there is significant margin for the RCS depressurization action.

The timing of the cue and the time when the creep rupture is predicted to occur are inputs to a base case calculation. The predicted creep rupture time is not required as an input to the time dependent HEP calculation.

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The aim of this evaluation is to calculate the HEP as a function of cue timing under PRA defined sequence conditions, the use of procedures, and the observed time required to accomplish each element of the task. Thus, the HEP can be calculated from the observed HEP(t) =Pla + Plb + P2 + P3 Eq. 1

where, P 1a is the probability of an error in detection, P Ib is the probability of error in assessing the situation, P2 is the probability of an error in the planning process, and P3 is the probability of error carrying out the action.

HRA assessments were performed for several plant conditions. These cases are described briefly in Table 1. Table 1 also provides the results of these assessments; and, Figure 1 graphically depicts these results versus time after the last cue occurs.

Table 1 Summary of Time De endent HEP data for Depressurizi n RCS after CETs reach 800 F Time after CET 1 Nominal with local 2 Nominal in CR with 3 Nominal in CR no cue (minutes) action (SDS-02) 2K07 Alarm 2K07 alarm 10 1.000 1.000 1.000 15 1.000 1.000 1.000 20 1.000 0.225 0.436 22.5 0.892 0.118 0.292 25 0.569 0.069 0.203 30 0.221 0.033 0.111 35 0.106 0.024 0.071 40 0.064 0.021 0.052 45 0.047 0.020 0.043 50 0.039 0.020 0.038 55 0.036 0.020 0.035 60 0.034 0.020 0.034 65 0.032 0.020 0.033 Page 4 of 6

Figure 1 Summary of Time Dependent HEPs for Depressurizing RCS after CETs reach 80OF Total HEP for mitigation of SG tube creep rupture potential versus time using ANO-2 Procedure 2203.012G cued by CET Indications (with and with out local action SDS-02 and Alarm 2K07) 1 000 01 Nominal with local action (SDS-02) 0.900

- 2 Nominal in CR with 21<17 AMarm 0800 -J 3 Nominal in CR no 21<07 alarm

+ 0.700

÷ 0.600 E 0.300

.0

a I

u0300 0.200 L*

0.100 0.000 10 20 30 40 50 60 Time in minutes from high CET cue Indications (five or more greater than 800 F)

The results in Table 1 illustrate the approximate time associated with an HEP of 0.25. In all cases, this time is expected to be in advance of the time of a SG tube creep rupture; these times are shaded in Table 1. Thus, a value of 0.25 for the probability of not opening the ECCS vent valves before SG tube creep rupture could be applied to all qualif~ying sequence frequencies.

Summary The proposedECCS venting action clearly reduces the potentialfor creep rupture of SG tubes by controlling the time of RCS depressurization. This in turn significantly reduces the threat of a temperature-inducedSGTR during the remainderof operatingcycle 14.

Specific findings follow:

" In general the crew's use of the plant procedures were very structured and clearly illustrated the phases of detection, situation assessment, response planning, and implementation.

"* The use of the dedicated cross-tie operator (DXO) to monitor the RCS depressurization cues, especially the CETs following any trip and perform the crossover connection, as necessary, during the remainder of ANO-2 Cycle 14 saves time in performing this action, and focuses attention on this action.

" The ECCS venting procedure SDS-02 is clear and is resistive to various types of cognitive and implementation errors. Its use by the DXO will assure tracking of the RCS Page 5 of 6

depressurization cues and that they will be opened quickly, when appropriate. The procedure also provides instructions on how to open these valves in the event that a safety train of DC power is lost.

"* The cues for RCS depressurization, including low SG level and high temperature CETs, are available to the DXO as long as either one of two safety trains of DC power is available.

"* The procedures can easily be accomplished in times much less than that assumed in the subject HRA. The times used for detection, situation assessment, response planning and implementation were very conservatively assessed. The published time of less than 10 minutes for SDS-02 implementation was verified by walk through.

"* The locations for SDS-02 local actions have clear makings, are well-lighted with emergency lighting, and provide ample space for carrying out the actions.

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PROCJWORK PLAN NO. PROCEDUREIWORK PLAN TITLE: PAGE: 4 of 113 2203.012A ANNUNCIATOR 2K01 CORRECTIVE ACTION CHANGE: 021-03-0 125 VDC/120 VAC RED CONT CENTER wnA 2D01 UNDERVOLT Page 68 ESF PANEL B 2RAI BUS UNDERVOLT Page 69 nNTPAE

denotes reflash capabilitv

PROCJWORK PLAN NO. PROCEDUREIWORK PLAN TiTLE: PAGE: 68 of 113 2203.012A ANNUNCIATOR 2K01 CORRECTIVE ACTION CHANGE: 021-03-0 ANNUNCIATOR 2K01 A-10 CONT CENTER 2D01 UNDERVOLT NOTE Steps marked with an asterisk (*) are Continuous Action Steps.

1.0 CAUSES 1.1 2D01 bus voltage *110 VDC (relay 27-2D01).

2.0 ACTION REQUIRED 2.1 Check 2D01 voltage on Computer Point (E2D01).

2.2 Check Battery Bank (2D-11) amps and voltage.

2.3 Check 2D11 Battery Charger (2D-31A or 2D-31B) amps and voltage.

2.4 IF battery charger amps are high AND 2D11 is discharging, THEN secure unnecessary 2D01 loads.

2.5 Refer to Loss of 125 VDC (2203.037).

2.6 Check for overloads or multiple grounds (both positive and negative).

2.7 Refer to Tech Specs 3.8.2.3 and 3.8.2.4.

2.8 IF BOTH of the following occur:

"* 2D01 Bus Undervoltage alarm valid

"* Original Steam Generators (OSGs) installed THEN direct the Dedicated Cross-tie Operator (DXO) to proceed to U2 Control Room AND obtain SDS02, EMERGENCY POWER FOR UNIT 2 ECCS VENT VALVES.

2.9 IF ALL of the following occur:

"* Original Steam Generators (OSGs) installed

"* 2D01 Bus undervoltage alarm valid

"* EITHER SG less than 70" WR

"* At least 5 available CETs above 800 0 F

"* A sustained Loss of ALL Feedwater has occurred THEN Control Room Staff implement SDS02, Section 2 - " Powering 2CV-4698-1 from Vital Bus 2D26".

3.0 TO CLEAR ALARM 3.1 Raise bus 2D01 voltage above setpoint.

4.0 REFERENCES

4.1 E-2451-2A

PROCJWORK PLAN NO. PROCEDURE/WORK PLAN TITLE: PAGE: 86 of 113 2203.012A ANNUNCIATOR 2K01 CORRECTIVE ACTION CHANGE: 021-03-0 ANNUNCIATOR 2K01 A-1I CONT CENTER 2D02 UNDERVOLT NOTE Steps marked with an asterisk (*) are Continuous Action Steps.

1.0 CAUSES 1.1 2D02 bus voltage *110 VDC (relay 27-2D02).

2.0 ACTION REQUIRED 2.1 Check 2D02 voltage on Computer Point (E2D02).

2.2 Check Battery Bank (2D-12) amps and voltage.

2.3 Check 2D12 Battery Charger (2D-32A or 2D-32B) amps and voltage.

2.4 IF battery charger amps are high AND 2D-12 is discharging, THEN secure unnecessary 2D02 loads.

2.5 Refer to Loss of 125 VDC (2203.037).

2.6 Check for overloads or multiple grounds (both positive and negative).

2.7 Refer to Tech Specs 3.8.2.3 and 3.8.2.4.

2.8 IF BOTH of the following occur:

"* 2D02 Bus Undervoltage alarm valid

"* Original Steam Generators (OSGs) installed THEN direct the Dedicated Cross-tie Operator (DXO) to proceed to U2 Control Room AND obtain SDS02, EMERGENCY POWER FOR UNIT 2 ECCS VENT VALVES.

2.9 IF ALL of the following occur:

"* Original Steam Generators (OSGs) installed

"* 2D01 Bus undervoltage alarm valid

"* EITHER SG less than 70" WR

"* At least 5 available CETs above 800OF

"* A sustained Loss of ALL Feedwater has occurred THEN Control Room Staff implement SDS02, Section 1 - " Powering 2CV-4740-2 from Vital Bus 2D27".

3.0 TO CLEAR ALARM 3.1 Raise bus 2D02 voltage above setpoint.

4.0 REFERENCES

4.1 E-2451-2A

PROCJWORK PLAN NO. PROCEDUREIWORK PLAN TITLE: PAGE: 3 of 58 2203.012G ANNUNCIATOR 2K07 CORRECTIVE ACTION CHANGE: 023-01-0 COOLING SHUTDOWN LI FEEDWATER EMERGENCY i

i0i LOSS OF RCS 2P7B SDC LEVEL FAILURE SUCTION HI/LO ON EFAS Page 41 Page 45 Page 49 rd LPSI PUMP SUCT PRESS HI/LO Page 42 1 LPSI DISCH HEADER PRESS HI/LO Page 46 2P7B BREAKER TRIP Page 50 LPSI PUMP SDC 2 2P7B MOTOR AMPS FLOW MOTOR HI/LO HI/LO OVERLOAD Page 43 Page 47 Page 51 SDC SUCTION CET EFW TRAIN A/B PRESSI TEMP HMISALIGNED Page 44 Page 48 PAGE 52 SPARE S*...f*i fSUCTION 2 P7B PRESS SPARE HI/ LO Page 53 2P7B DISCH PRESS SPARE SPARE HI/LO Page 54 B /G FLOW SPARE SPAR HI/LO I Page 2P7B TO56 2P7B TO B S/G FLOW SPARE SPARE HI/LO Page 56

SW TO 2P7B PRESS ITSPARE S PARE LO Page 57 2P7B RM CLR 2VUC-6B SPARE SPARE TROUBLE Page 58 8

PROCJWORK PLAN NO. PROCEDURE/WORK PLAN TITLE: PAGE: 48 of 58 2203.012G ANNUNCIATOR 2K07 CORRECTIVE ACTION CHANGE: 023-01-0 ANNUNCIATOR 2K07 D-8 CET TEMP HI NOTES

1. This alarm set at 700°F with Original Steam Generators (OSGs) installed.

2. Steps marked with an asterisk (*) are Continuous Action Steps.

1.0 CAUSES 1.1 CET temperature greater than variable alarm setpoint (2TI-4793).

2.0 ACTION REQUIRED 2.1 Verify temperature being controlled within desired band.

2.2 Use SPDS CET Display to verify temperature.

2.3 IF ALL of the following conditions exist:

"* Original Steam Generators (OSGs) installed

"* At least 5 available CETs above 800°F

"* A sustained Loss of ALL Feedwater has occurred THEN perform the following 2.3.1 Open ECCS Vent Valves

2CV-4698-1

2CV-4740-2 2.3.2 Declare Alert based on EAL 9.2 using 1903.011M, Alert Emergency Direction and Control Checklist - Shift Superintendent.

2.3.3 GO TO 2202.009, Functional Recovery 2.4 IF due to SDC failure, THEN GO TO Loss of Shutdown Cooling (2203.029).

2.5 Adjust variable alarm setpoints as necessary.

3.0 TO CLEAR ALARM 3.1 Lower CET temperature below variable alarm setpoint (2TI-4793).

4.0 REFERENCES

4.1 E-2455-4

INSTRUCTIONS CONTINGENCY ACTIONS N19. IF EITHER of the following conditions exist:

A. EITHER SG with level less than 70 inches.

B. RCS TC rising in an uncontrolled manner.

THEN establish Heat Removal via Once Through Cooling as follows:

A. Close MSIVs from Control Room.

B. Manually actuate SIAS and CCAS.

C. Verify ALL HPSI Cold Leg Injection MOVs open.

D. Verify ALL available Charging pumps running.

E. Check 4160v Vital buses 2A3 and 2A4 E. Perform the following:

energized from offsite power.

1) IF EITHER 4160v Vital bus energized from offsite power, THEN perform the following:

a) Commence aligning third HPSI pump to associated bus.

b) WHEN third HPSI pump alignment complete, THEN verify third HPSI pump running.

2) IF ANY 4160v Vital bus energized from DG, THEN perform the following:

a) Verify ONE HPSI pump running on train supplied by DG.

b) GO TO Step 19.G.

(Step 19 continued on next page)

PROC NO TITLE REV DATE PAGE 2202.006 LOSS OF FEEDWATER 004-02-0 6/25/00 16 of 33

INSTRUCTIONS CONTINGENCY ACTIONS

19. (continued)

F. Verify three HPSI pumps running.

G. Verify at least ONE HPSI pump running. *G. IF NO HPSI pumps running, THEN perform the following:

1) Verify MSIVs closed

2) GO TO step 19.J.

H. Open ECCS PZR Vent valve H. Open LTOP Relief Isolation valve (2CV-4698-1).' (2CV-4741-1).

I Open LTOP/ECCS Relief Isolation valve 1. Perform the following:

(2CV-4740-2).

1) Open LTOP Relief Isolation valve (2CV-4731-2).

2) Open LTOP Relief Isolation valve (2CV-4730-1).

J. Maintain BOTH SG pressures 950-1050 psia using upstream ADVs or upstream ADV isolation MOVs.

K. GO TO 2202.009, Functional Recovery.

20. Check FW flow restored to at least ONE *20. IF FW flow NOT restored, THEN RETURN SG by ANY of the following: TO Step 11.

"* EFW

"* AFW

"* MFW

"* Condensate

"*21. Maintain SG pressure less than 1050 psia:

A. Control SG pressure using SDBCS Bypass valves or ADVs.

B. Check at least ONE Condensate pump B. Start ONE Condensate pump using running. 2106.016, Condensate and Feedwater Operations.

(Step 21 continued on next page)

21. (continued)

PROC NO TITLE REV DATE PAGE 2202.006 LOSS OF FEEDWATER 004-02-0 6/25/00 17 of 33

PROCJWORK PLAN NO. PROCEDUREIWORK PLAN TlTLE: PAGE: 21 of 60 1015.001 CONDUCT OF OPERATIONS CHANGE: 05203-0 6.7 Auxiliary Operator 6.7.1 The Auxiliary Operator reports to the CRS of their respective Unit and is responsible for all operational activities executed outside the Control Room associated with secondary auxiliary components and systems.

6.7.2 Specific responsibilities and authorities assigned to the Auxiliary Operator are the same as those stated in Section 6.6.2 and 6.6.3 for the Waste Control Operator.

CAUTION Dedicated Cross-tie Operator (DXO) is a Unit 2 specific watchstation and SHALL be manned when Unit 2 Original Steam Generators (OSGs) are installed.

6.8 Dedicated Cross-tie Operator (DXO) 6.8.1 The Dedicated Cross-tie Operator (when manned) reports to the CRS of Unit 2 and is responsible for implementation of Severe Accident Management Guideline (SAMG) Developed Strategy 02 (SDS02), "EMERGENCY POWER FOR UNIT 2 ECCS VENT VALVES".

6.8.2 Specific responsibilities and authority assigned to the Dedicated Cross-tie Operator include the following:

"* Maintain manned status when Original Steam Generators (OSGs) are installed on Unit 2.

"* Maintain response capability with appropriate equipment

- Radio

- Flashlight

- Key to Door 257 (Room 2091 AKA 2B53 Room)

"* Implement SDS02 when directed by the CRS or the Technical Support Center (TSC) . A copy of SDS02 is housed with the DC Bus connection cable at cabinet/job box outside Door 257.

6.9 Shift Engineer (SE)/Shift Technical Advisor (STA) 6.9.1 The SE/STA is responsible to be within operable communication range and available to the Control Room within ten minutes of call by the Control Room personnel.

6.9.2 The SE/STA is responsible to maintain respirator qualifications, and if corrective eyewear is normally needed, maintain appropriate SCBA eyewear (spectacles or contact lenses) readily available.

PAGE 6 OF 42 SHIFT TURNOVER CHECKLIST MODES 1 - 4 PAGE 1 OF 12 INSTRUCTIONS:

1.0 Circle YES, NO or N/A for each item in any desired order.

2.0 N/A items not applicable due to mode or being aligned to other train.

3.0 If NO is circled, then explain in the Remarks section.

4.0 If NO is circled on a Tech Spec (TS) required component, then refer to associated Tech Spec Action Statement and notify opposite unit, as applicable.

Mode: Date: Time:

A. SDBCS ALIGNMENT (2C02)

1. 2CV-1002 (A S/G Upstream ADV Isol) closed YES NO

2. 2CV-1052 (B S/G Upstream ADV Isol) closed YES NO

3. 2CV-1001 (Upstream ADV) closed, HIC in Manual, permissive in Off YES NO

4. 2CV-1051 (Upstream ADV) closed, HIC in Manual, permissive in Off YES NO

5. 2CV-0301 (DDV) closed, HIC in Auto and permissive HS in Auto YES NO

6. 2CV-0305 (DDV) closed, HIC in Auto and permissive HS in Auto YES NO

7. 2CV-0302 (Bypass Vlv) closed, HIC in Auto, permissive HS in Auto YES NO S. 2CV-0303 (Bypass Vlv) closed, HIC in Auto, permissive HS in Auto YES NO

9. 2CV-0306 (Bypass Vlv) closed, HIC in Auto, permissive HS in Auto YES NO B. SHUTDOWN COOLING (2C04)

Two independent ECCS subsytems required operable in Mode 1, 2 & 3 with PZR pressure >1700 psia. (TS 3.5.2)

1. 2CV-5091 (LPSI Disch Header) open. YES NO N/A

2. 2HS-5091 in ESF with the key removed. YES NO N/A

3. 2FIC-5091 (LPSI Disch Hdr Flow) in Auto & set at -2500 gpm. YES NO N/A

4. IF 2TI-4793 NOT in use for SDC, YES NO N/A THEN 2TI-4793 energized AND CET alarms set at 7000 F.

form no. j change no.. 1 form title:

SHIFT TURNOVER CHECKLIST MODES I - 4 no.

Sform 1015.016 B change no..

1021-02-0 1 I form title: i 05.1 B 02--0 i i SITTROE HCLS OE

PAGE 17 OF 42 SHIFT TURNOVER CHECKLIST MODES 1 - 4 PAGE 12 OF 12 X. MSIS

1. IF a MSIS actuation channel becomes inoperable in 2C39 or 2C40, THEN restore the actuation channel within one hour or be in Hot Standby within 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months .

2. IF a component required for MFW isolation becomes inoperable (i.e., a Condensate, MFW, or Heater Drain pump will not trip on MSIS),

THEN restore the component within 48 hours5.555556e-4 days 0.0133 hours 7.936508e-5 weeks 1.8264e-5 months or place it in its MSIS actuated state. Otherwise be in Hot Standby in 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months .

COMMENTS:

If position manned, then list on shift personnel:

s/s CRS CRSA TRO CBOR CBOT WCO AO EOP SE DXO*

IF Original Steam Generators (OSGs) installed, THEN Dedicated Cross-tie Operator (DXO) manned.

PERFORMED BY:

REVIEWED BY:

form title: form no. change no..

SHIFT TURNOVER CHECKLIST MODES 1 - 4 1015.016 B 021-02-0

TABLE OF CONTENTS PAGE SECTION 1 Powering 2CV-4740-2 from Vital Bus 2D27 ...................... 2 SECTION 2 Powering 2CV-4698-1 from Vital Bus 2D26 ...................... 3 ATTACHMENT 1 DXO Control Room Duties ....................................... 4 EXHIBIT 1 SAMG ECCS Vent Initiation Criteria ............................ 5 Reference ER002624N201 MIS-00-006

SAMG DEVELOPED SAMG DEVELOPED STRATEGY TITLE:

PAGE: 2OF 5 STRATEGY SAMG DEVELOPED STRATEGY 02 SDS-02 EMERGENCY POWER FOR UNIT 2 ECCS VENT VALVES SECTION 1 Powering 2CV-4740-2 from Vital Bus 2D27 Loss of GREEN TRAIN Page 1 of 1 NOTES

" Operator actions should NOT be delayed for Health Physics, Security, or any other concerns.

"* Elevators should NOT be used when performing this procedure.

"* Prompt completion of these actions overrides all other procedures, technical specifications, or verbal directions other than those from Operations Management.

" Communications to DXO should use radio or telephone (extension 6091 for Corridor 340 and 6093 for 2B53 Room).

1.0 Entry 0 Performance of this attachment is directed by TSC or Control Room 2.0 ACTIONS 2.1 Open Valve 2CV-4698-1 (ECCS Vent Valve) from Control Room.

2.2 Open Breaker 2D02-21 (2D26 MCC Supply).

2.3 Retrieve DC Bus connection cable from cabinet/job box outsid e 2B53 Room and proceed to 2B53 Room (Door 257).

2.3 Open Breaker 2D27-A2 (Upstream Feeder Breaker to 2CV-4698-I).

I CAUTION Breaker 2D26-A2 (Upstream Feeder Breaker to 2CV-4740-2) MUST be opened to prevent energizing the entire 2D26 Bus.

2.4 Open Breaker 2D26-A2.

2.5 Open raceway between rows 1 and 2 of the following MCCs:

MCC cabinet 2D26

MCC cabinet 2D27.

2.6 Connect DC Bus connection cable to plugs in each raceway.

2.7 Close Breaker 2D27-A2.

2.8 WHEN power restored to 2CV-4740-2 by DXO, THEN open valve 2CV-4740-2 from Control Room.

MIS-00-006

SAMG DEVELOPED SAMG DEVELOPED STRATEGY TITLE:

PAGE: 3OF 5 STRATEGY SAMG DEVELOPED STRATEGY 02 SDS-02 EMERGENCY POWER FOR UNIT 2 ECCS VENT VALVES SECTION 2 Powering 2CV-4698-1 from Vital Bus 2D26 Loss of RED TRAIN Page 1 of 1 NOTES Operator actions should NOT be delayed for Health Physics, Security, or any other concerns.

"* Elevators should NOT be used when performing this procedure.

"* Prompt completion of these actions overrides all other procedures, technical specifications, or verbal directions other than those from Operations Management.

" Communications to DXO should use radio or telephone (extension 6091 for Corridor 340 and 6093 for 2B53 Room).

1.0 Entry

Performance of this attachment is directed by TSC or Control Room 2.0 ACTIONS 2.1 Open Valve 2CV-4740-2 (ECCS Vent Valve) from Control Room.

2.2 Open Breaker 2D01-21 (2D27 MCC Supply) 2.3 Retrieve DC Bus connection cable from cabinet/lob box outsid e 2B53 Room and proceed to 2B53 Room (Door 257).

2.3 Open Breaker 2D26-A2 (Upstream Feeder Breaker to 2CV-4740-2).

I CAUTION Breaker 2D27-A2 (Upstream Feeder Breaker to 2CV-4698-1) MUST be opened to prevent energizing the entire 2D27 Bus.

2.4 Open Breaker 2D27-A2.

2.5 Open raceway between rows 1 and 2 of the following MCCs:

MCC cabinet 2D26

MCC cabinet 2D27.

2.6 Connect DC Bus connection cable to plugs in each raceway.

2.7 Close Breaker 2D26-A2.

2.8 WHEN power restored to 2CV-4698-1 by DXO, THEN open valve 2CV-4698-1 from Control Room.

MIS-00-006

SAMG DEVELOPED SAMG DEVELOPED STRATEGY TITLE: PAGE: 4OF 5 STRATEGY SAMG DEVELOPED STRATEGY 02 SDS-02 EMERGENCY POWER FOR UNIT 2 ECCS VENT VALVES ATTACHMENT 1 DXO Control Room Duties Page 1 of 1 NOTES

1. Group Displays 8, 9, 10 and 11 are set up for the operator to monitor CETs and Steam Generator Wide Range Level. Each group represents a quadrant of the core. Groups 8 and 10 contain Steam Generator Wide Range Level.

Group 11 contains Average CET temperature.

2. Use the "Display FWD" and Display Reverse" buttons to toggle between page 1 and page 2 of each group display.

1.0 IF SPDS available, THEN continuously monitor CETs AND Steam Generator Wide Range Level at 2C-69A as follows:

1. Verify CRT 2QI-9011 showing "Group/Trend Display" using black button below CRT

2. Type "D3" (TAB)

3. For "Enter Group Number" type "8(9) (10) (11)" [TAB)

4. For "Column Number To Be Reassigned" type "NONE" [TAB)

5. For "Enter Trend Interval" type "30" [TAB]

6. For "Enter Start Time" type "NOW" [TAB)

7. For "Enter Stop Time" type "NONE" [TAB)

8. For "Enter Output Device" type "D" [TAB)

9. Press "EXECUTE" 2.0 IF SPDS NOT available, THEN continuously monitor readings at the following locations:

Steam Generator Wide Range Level 2LI-1079-I(2) and 2LI-1179-I(2) at 2C02

CETs at RVLMS cabinets 2C-388-1(2) using 2105.003, Reactor Vessel Level Monitoring System Operations 3.0 IF ALL of the following occur:

Original Steam Generators (OSGs) installed

At least 5 available CETs above 800'F

EITHER Steam Generator < 70" Wide Range

A sustained Loss of ALL Feedwater has occurred THEN inform the Shift Manager of the need to perform the following:

3.1 Open ECCS Vent Valves* *IF DC NOT available to either ECCS Vent, 2CV-4698-1 THEN implement appropriate section of SDS02

2CV-4740-2 3.2 Declare Alert based on EAL 9.2 using 1903.011M, Alert Emergency Direction and Control Checklist - Shift Superintendent.

3.3 GO TO 2202.009, Functional Recovery MIS-00-006

SAMG DEVELOPED SAMG DEVELOPED STRATEGY TITLE: PAGE: 5OF 5 STRATEGY SAMG DEVELOPED STRATEGY 02 SDS-02 EMERGENCY POWER FOR UNIT 2 ECCS VENT VALVES EXHIBIT 1 SAMG ECCS Vent Initiation Criteria Page 1 of 1

Original Steam Generators (OSGs) installed

At least 5 available CETs above 800 0 F

EITHER Steam Generator < 70" Wide Range

A sustained Loss of ALL Feedwater has occurred MIS-00-006 MIS-00-006

Dedicated Cross-Tie Watch Study Guide In the event of a total loss of feedwater it may become necessary to depressurize the RCS to initiate feed and bleed cooling. Additionally, if high pressure safety injection and low pressure safety injection is unavailable in conjunction with a total loss of feedwater, it is critical that the RCS be depressurized to avoid the potential of steam generator tube failure due to the severe accident conditions. The ECCS vent valves can be used to depressurize the RCS. These valves relieve steam from the pressurizer to the quench tank. The ECCS vent path has two DC powered valves in series, so they may be operated with a complete loss of AC power. The ECCS vent valves are powered from opposite 125 volt vital DC power. A problem exists, looking at single failure criteria, if one train of DC power is lost.

A contingency action has been developed to deal with the loss of one train of 125 volt vital DC. Pigtails with female connectors have been connected to the ECCS vent valve power supplies on 2D26/D27 buses and hung in the raceway next to the affected valves. Outside the 2B-53 room is a locked JOBOX with a procedure and a 30' crosstie cable with male connectors on each end.

When a loss of a DC bus occurs, the annunciator corrective action procedure directs the control room to dispatch the Dedicated Cross-Tie Watch (DXO) to the control room. The DXO will commence monitoring CETs and Steam Generator Wide Range Level using SDS02, ATTACGHMENT 1, DXO Control Room Duties (posted on side of 2C-69A). The DXO will also be dispatched to the control room upon Reactor Trip. A plant page will be made for Rx trip as a part of Standard Post-Trip Actions. Once the ECCS Vent Initiation criterion is met as described in SDS02 EXHIBIT 1, the Control Room Staff will implement the appropriate section of SDS02.

If no loss of DC has occurred the Control Room Staff will open the ECCS Vent Valves. If a loss of one DC train has occurred (necessitating ECCS Vent Valve Power Cross-tie) the Control Room Staff will open the ECCS Vent valve that is energized. The DXO will obtain a copy of SDS02 sections 1 or 2 (staged at 2C-69B South end) and proceed to Corridor 340 to commence his local actions.

The DXO will then open the DC bus supply breaker to the deenergized MCC and proceed to the 2B53 room. The DXO will then open the upstream feeder breakers to both ECCS vent valves. The DXO will then connect the crosstie cable. Once the cable connectors are locked in place, the feeder breaker to the ECCS vent valve on the energized bus is closed sending DC power to the opposite train vent valve. The second ECCS vent valve is then opened from the control room commencing depressurization of the RCS.

The control room will be cued to this action by communication from the DXO or by observing the valve position indication returning. The energized ECCS Vent valve de-energizes and then both valves re energize when the DXO completes his local actions.

The evolution is expected to take less than 15 minutes (and has been time-validated at less than 10 minutes) but the need for proper self-checking can not be ignored. This evolution is considered vital.

DO NOT STOP for anyone (including HP and security) unless the operator's life or health is at immediate risk.

Since the response needs to be timely, the DXO shall carry a radio, flashlight, and set of spare keys with them at all times. The keys will be tracked using the key log in the Shift Manager's office. Proper turnover needs to include the updating of the key log. The qual card for this watch has been given to ROs, NLOs, and trainees. It is the Shift Manager's responsibility to ensure that he has a qualified person available each shift. The DXO watchstander's name is recorded on the Shift Turnover Checklist.

Additionally, a shiftly inventory of the JOBOX will be performed and documented on the Auxiliary Operator Turnover Checklist.

Unit 2 Dedicated Cross-Tie Watch Qualification Guide ANO-2-QC-AO-DXOQC Revision 1 Dedicated Cross-Tie Watch Trainee SSN ANO-2-QC-AO-DXOQC 1 of 5

QUALIFICATION REQUIREMENTS AND GUIDELINES INTRODUCTION AND INSTRUCTIONS:

This guide has been written to train and establish a dedicated cross-tie watch to ensure that upon a loss of DC to Bus 2D26 or 2D27, the associated de-energized ECCS Vent Valve, 2CV-4740-2 or 2CV-4698-1, can be re energized from the operable bus. This will ensure that the ECCS Vents remain available to de-pressurize the RCS in the event of an over pressurization event. This will minimize the potential to exceed a delta pressure between the RCS and Steam Generators of greater than 3 time normal.

The Dedicated Cross-Tie Watch training sequence consists of on the job training including a knowledge checkout and performance task. After this, a final certification shall be obtained from a Shift Manager.

Upon qualification, the qualification guide will be entered in the trainee's plant training record under ANO-2-QC-AO-DXOQC QUALIFICATION CARD SECTIONS:

1.0 References - This subsection provides a list of documents that should be used during the preparation, training and evaluation phases. It should be noted many of the references are listed only to serve as an aid to the trainee during his/her research.

2.0 Training Class Requirements - AO Training Class Requirements - This subsection will be signed off by a Unit 2 trainer. Requirements for the signature are either:

Attendance of the lecture and satisfactory performance on an examination on the lecture material OR Qualified as an Auxiliary Operator or above.

3.0 System Knowledge Requirements - This subsection contains objective based knowledge requirements designed to ensure the trainee has adequate knowledge of each system/area of the Qualification Guide. The current revision of the specified reference documents from Section 1.0 shall be used as the training standard to ensure correct and complete responses. However, the reference documents are not required to be open during the evaluation. Additional knowledge's that may be required by examiners should be in accordance with approved plant procedures, work plans, notices or technical references.

CAUTION:

THE TRAINEE SHALL NOT PERFORM ANY PERFORMANCE TASK UNLESS BEING DIRECTLY SUPERVISED BY A QUALIFIED AUXILIARY OPERATOR OR ABOVE.

4.0 Performance Tasks - this subsection provides training on tasks the operator will be performing in the role as a qualified Dedicated Cross-Tie Watch and then evaluates the trainee's ability to perform the task. Prior to Evaluation on a task, the trainee shall have completed the System Class (Section 2.0) and System Knowledge Requirements (Section 3.0). The trainee may receive the Performance Task Trainin signature on a task prior to completing the System Class (Section 2.0) or System Knowledge Requirements (Section 3.0). The On The Job Training (OJT) shall utilize the "4-Ps" approach to OJT.

The OJT Instructor (OJTI) and Task Performance Evaluator (TPE) shall be qualified IAW 1064.062, On The Job Training.

1. Preparation: The OJTI analyzes the task and determines what parts can be performed by the trainee (allowing for plant conditions), what tools and equipment are needed, what documentation will be needed, etc.

2. Presentation: The OJTI explains to the trainee what should be done, what should be learned, the trainee's role in the task, and what safety measures are required. The OJTI then demonstrates the task explaining why each function is performed.

3. Practice: The trainee performs the task under the supervision of the OJTI and receives coaching.

The trainee should repeat the task or parts of it as many times as necessary to fill comfortable with the elements of the task.

ANO-2-QC-AO-DXOQC 2 of 5

QUALIFICATION REQUIREMENTS AND GUIDELINES

4. Performance: The trainee independently performs the entire task (preferably under actual working conditions) under the observation of the Task Performance Evaluator (TPE). The trainee's performance shall be evaluated by using applicable procedures as a standard to measure against.

Two signatures are necessary for completion of each performance task. The first signature signifies the traininghas been completed. The second signature by the TPE is for the evaluation of the task being performed independently by the trainee. When possible, the training and evaluation should be separated by some time frame. This allows the trainee the opportunity to "season" the newly acquired knowledge and the evaluation is a better test of the ability of the trainee to retain information and use it when required by plant operations.

An action code indicates the action level required to successfully complete an evaluation. The following codes are used:

PERFORM (P) - Supervised hands-on task performance by the trainee during which he/she shall use the appropriate procedure(s), limits and precautions, and safety precautions while independently performing the task.

SIMULATE (S) - Supervised session in which the trainee independently shows equipment or component physical location, expected indication, and how equipment/components would be manipulated without actual hands-on manipulation of the equipment/component The trainee shall demonstrate the use of appropriate procedure(s), limits and precautions and any safety precautions.

When more than one of these actions is acceptable in completing an item, the preferred actions is indicated first, with acceptable alternatives listed in decreasing order of preference.

OJT MONITORING BY LINE MANAGEMENT:

Monitoring during the training and evaluation phases may be performed by line management. These observations are to provide feedback to the OJT Instructors and Task Performance Evaluators on their performance, and to identify needed improvements in Instructor/Evaluator training material or content. This monitoring is governed by 1064.062, On the Job Training. The observations should be documented on:

Form 1064.062B, Evaluation of OJT Instructors

Form 1064.062F, Evaluation of Task Performance Evaluators 5.0 System Certification - This subsection is designed to provide the trainee with the following:

5.1 A system certification following an oral examination by a Unit 2 Shift Manager. This certification shall occur after all other subsections of the applicable system have been completed.

5.2 Following certification, the trainee is capable of performing unsupervised operation of cross connecting 2D26 and 2D27 to power up 2CV-4698-1 and 2CV-4740-2.

SEQUENCE AND REPORTING REQUIREMENTS Sections 2.0 and 3.0 shall be completed prior to conducting the performance task evaluation listed in Section 4.0 ANO-2-QC-AO-DXOQC 3 of 5

Name SSN Dedicated Cross-Tie Watch Objective: The objective of the Unit 2 Dedicated Cross-Tie Watch qualification guide is to ensure that operators possess the knowledge and skills necessary to independently perform the assigned duty in a safe and efficient manner.

1.0

References:

1.1 STM 2-3, Reactor Coolant System 1.2 STM 2-32-5, 125 VDC Electrical Distribution System 1.3 COPDOO 1, Self-Verification/Additional Verification 1.4 COPD-15, Communication Standards 1.5 SDS-02, SAMG Developed Strategy 02- Emergency Power for Unit 2 ECCS Vent Valves 1.6 ER 002624N20 1, Install Emergency Power Cross-Connect for Unit 2 ECCS Vent Valves 1.7 2105.003, Reactor Vessel Level. Monitoring System Operations 1.8 2105.014, Safety Parameter Display System Operation 2.0 Training Class Requirements:

2.1.1 ANO-2-LP-AO-ED125, 125 VDC Electrical Distribution, or qualified as an AO or above.

Date OPS Trainer 3.0 Knowledge Requirements:

3.1 Discuss the function and importance of ECCS vent valves during Severe Accident Mitigation.

3.2 Discuss the type of valve ECCS vents are and where their controls are located.

3.3 Discuss the affect of a loss of 2D01 or 2D02 on the ECCS vent valves.

3.4 Discuss the purpose and use of Safety Parameter Display System and RVLMS.

3.5 Discuss the duties and responsibilities of the Dedicated Cross-Tie Watch.

3.5.1 Initiating event 3.5.2 What control room actions are required 3.5.3 Cross-tie of ECCS vents power supply 3.5.3 Use of self-verification 3.5.4 Operation of a DC breaker 3.5.5 Operation of a molded case breaker 3.5.6 Response time required 3.5.7 Expectation to remain on station 3.6 Equipment required for watchstanding.

3.7 Purpose and use of key log.

3.8 Proper communication and radio use.

3.9 Turnover of watchstanding duties.

/

Date CRS/SM 4.0 Performance Tasks:

4.1 Cross connect 2D26 and 2D27 to power 2CV-4740-2 from 2D27 (SDS-02, Section 1)

/ / (P/S)

Date Training Date Evaluation 4.2 Cross connect 2D26 and 2D27 to power 2CV-4698-1 from 2D26 (SDS-02, Section 2)

(P/S)

Date Training Date Evaluation ANO-2-QC-AO-DXOQC 4 of 5

Dedicated Cross-Tie Watch 4.3 Locate and monitor CET temperatures and Steam Generator levels on SPDS (SDS-02, Attachment 1)

/ / (P/S)

Date Training Date Evaluation 4.4 On a loss of SPDS, locate and monitor CET temperatures on RVLMS and Steam Generator levels on 2C04 (SDS-02, Attachment 1)

/ (P/S)

Date Training Date Evaluation 5.0 Final Certification:

Date Shift Manager ANO-2-QC-AO-DXOQC 5 of 5

Attachment to 2CAN060018 Attachment 5 HRA Modeling Process

Modeling Process Employed in Independent Human Reliability Analysis (HRA) of the RCS Depressurization Action to Mitigate the Risk of a Temperature-Induced Steam Generator Tube Rupture at ANO-2 HRA modeling process The HRA modeling process employed in the Independent Human Reliability Analysis (HRA) of the RCS Depressurization Action to Mitigate the Risk of a Temperature-Induced Steam Generator Tube Rupture at ANO-2 has been described in EPRI TR-107623. The supporting evaluations use the logic tree methodology in EPRI TR-100259 to evaluate the likelihood of cognitive errors associated with detection and situation assessment. The time dependent modeling uses the human cognitive reliability (HCR) model upgraded through the information and data gathered in the Operator Reliability Experiments and the implementation action portion is evaluated using the accident sequence evaluation program (ASEP) approach.

This HRA process provides a robust method for verifying that the new procedures are error resistive, and provides the capability of evaluating the reliability of performing the action from the time that the cue is received. The reliability of the action at a given time can be compared with the time predicted for hot gas circulation and creep rupture of a tube to verify that there is significant margin for the RCS depressurization action.

The timing of the cue and the time when the creep rupture is predicted to occur are inputs to a base case calculation. The predicted creep rupture time is not required as an input to the time dependent HEP calculation.

The aim of this evaluation is to calculate the HEP as a function of cue timing under PRA defined sequence conditions, the use of procedures, and the observed time required to accomplish each element of the task. Thus, the HEP can be calculated from the observed times via the following expression, HEP(t) = Pla + P1b + P2 + P3 Eq. 1

Where, Pla is the probability of an error' in detection, Plb is the probability of error in assessing the situation, P2 is the probability of an error in the planning process, and P3 is the probability of error carrying out the action.

Time periodassessment Each element in Equation 1 requires time for the activity, thus an overall time period equation can be developed for the time period required for each action. This helps verify the feasibility of the ECCS venting action.

SError here refers to those errors that are not recovered within the time frame of interest Page 1

Time period required = tr = tPla + tPlb + tP2 + tP3. Eq. 2 The nominal time period for each element in Equation 2 can be estimated by using Job Performance Measures, published simulator measures, procedure walkthroughs, and plant specific simulator observations. The clearest measures are for tP3, which measures the time period required to perform the physical action once the decision has been made to take the action. Time period measures for tPla and tPlb are observable in simulated events by noting the time difference between the initiating event and when the crew reports an alarm, and secondly when the plant state is described with accuracy to the SRO. These time periods are typically very short if all information is within the control room; however, if local evaluations are necessary this time period can be much longer.

It is assumed that the remaining time period is available for response planning. The expected time period for response planning, tP2, generally has the larger variability than the others do, which is accounted for in the HCR model. Time period estimates for tP2 can be obtained from reported simulator measures of T1 /2, or from observations of simulated accidents where the crew plans the response to the event and authorizes either control room or local actions 2 .

Once the time periods for completion of the tasks or procedure for each tP are defined, assuming that the cue occurs at t = 0, then the HCR model can be used to calculate the HEP as a function of time. Also, a situation specific curve can be generated to represent the time dependent human reliability. The HCR model parameters are defined as ta (time period available), tn (a normalized time), and cy (a value representing variability in the operating crew decision making about the response).

Time period available = ta (for response planning) = ts - ( tPla + tPlb + tP3 ).

The time period available (ta) is calculated either as the difference between the total allowed system response time period (ts) and all known time periods except for tP2, or as the time period after the cue ta(t) which is independent of the system response time period ts. Note that tP2 =

T 1 /2 , the median response time period, is the time period taken for response planning which is input to the HCR model, and is part of time period available (ta).

The first method requires development of a time line between the cue and the change of state of the plant (in this case the time from the cue to a SG tube failure due to creep rupture). This method was used for the base case estimate. The result is a single point estimate of the P2 value that is combined with the other estimates to produce an overall HEP at the limiting condition.

The example result is less than .04. In this case, there can be significant uncertainty in the value of the system time window generated by MAAP.

Therefore, a second method is used by substituting a variable time period from the cue for the time period available (ta). In this case, ta(t) is independent of ts, and is used to estimate the 2 If the times for tPla, tPlb, and tP2 following a cue are observable only as a single value, then it is also possible to estimate T1 /2 as the sum of tPla, tPlb, and tP2.

Page 2

probability of P2(t) as a function of time from the cue. With this substitution, a time dependent function can be generated which predicts the non-completion probability as a function of the time since the cue and the time required to accomplish the action. This is independent of any thermal hydraulic model. This case was used to examine margins between the calculated time periods for SG creep rupture and the time periods for fixed HEP estimates. Since the estimates for both the operator response and the SG tube creep rupture failure begin with the same cue of CETs = 800 F, the margin on time period between the operator success and SG tube failure can be examined.

P2 assessment The HRC model used to estimate the value of P2 as a function of time from the cue for action is shown in Equation 3.

P2(t) = 1-c1(ln(tn)/a)) Eq. 3 The term (Dis the standard normal distribution. The term tn is the normalized time is defined as ta(t)/Ti/ 2 where TI/2 is the best estimate of the median time for response planning. The term a is a measure of the dispersion in response times for normalized results of many simulations. The dispersion parameter is a strong function of the way that the cue is received. For example, if the cue such as "Five CETs Reach 800 F" is received with little or no prior warning the larger dispersion factor applies (CP3 = .75). If an early warning cue such as "CET alarm at 700 F" is received prior to the action then a lower dispersion factor applies (CP2 = .57).

Thus, the P2 term provides the major variance in time to the HEP equation. This assumes that the variances on the times for PI and P3 are very small and can be neglected. To account for uncertainty in P1 and P3, large time periods based on observations in the simulator are selected to cover these elements.

HEPcalculationassumptions The total HEP is based on the combination of probability assessments for detection, situation assessment, response planning and implementation. In each probability assessment conservative assumptions are made. These include the assumptions that were made in this review.

(1) Application of the new operator mitigating actions within the current ANO-2 Core Damage Frequency (CDF) results initially assumes that no mitigation actions are included in the sequence frequency estimate (HEP = 1.0).

(2) The base ANO-2 CDF results do include recovery actions (restoring the function represented by the failed component) on a cutset by cutset basis. The dependence between post initiator recovery failures and post core damage mitigation actions is judged to be very small, because of (1) implementing a new procedure and its change in mitigation strategy, (2) the separation in time for recovery and mitigation actions, (3) additional support from the Technical Support Center (TSC) may be available for mitigating actions, and (4) the use of a dedicated cross-tie operator to perform the mitigating action. Also, a calculation using the ASEP/THERP models for multiple action dependence, the HEP for diagnosis of a second event within forty minutes is .001 * .1 =.0001 from ASEP Table 8-2 (10) modified by Table Page 3

8-3 item 2. Therefore, in sequences with previous operator errors the dependency is judged to be very low.

(3) Assessments of failure to perform the mitigation actions were developed by using time dependent HEP models. The inputs are assessments of time periods for accomplishing various parts of the action (e. g., detection, situation assessment, response planning and implementation) following a cue. The output is an estimated HEP as a function of time or at a particular time period that matches the time between the cue and when a significant change in plant state that is calculated to occur if the action is not taken or is taken in a way that is not effective.

(4) The P2 term provides the major variance in time to the HEP equation. This assumes that the variances on the times for P1 and P3 are small enough to be neglected. To account for this uncertainty large time periods are selected to cover these elements (e. g, 95% confidence that the P1 and P3 actions will be completed in the allowed time).

(5) Application of procedure SDS-02 (opening the ECCS vent valves) will mitigate the potential for creep rupture if applied before hot gas circulation begins in all high-RCS low-steam generator pressure core damage scenarios. This assumption also applies in the uncontrolled depressurizations where either the PSRV sticks open, or the hot leg piping fails before the SG tube.

Base Case Point Estimate The HRA models were exercised on an initial base case to estimate a HEP for the current estimated time window for damage due to creep rupture following a cue of 800 F on the CETs.

The result demonstrates that the HEP is about .04 based on a total system time window of 44 minutes.

Cuesfor Action The RCS depressurization action assumes that all of the following cues are present:

"* Original SG installed (through the end of cycle 14)

"* Sustained loss of all feedwater sources

"* Less than 72" on either SG

"* At least five CETs read above 800 F.

Human InteractionError Operators fail to open ECCS vent valves 2CV-4698-1 and 2CV-4740-2.

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Consequence of the error The RCS pressure remains high when hot gas circulation begins which increases the chance of creep rupture in degraded SG tubes and a subsequent bypass of the containment.

Dependencies The two ECCS vent valves are arranged in series on the ECCS vent line piping. One of the valves is powered by the "red" train of DC power; the other is powered by the "green" train of DC power. Thus, on the loss of either train of DC power ("red" or "green"), the ECCS vent line cannot be opened via electrical operation of the ECCS vent valves from the control room. And, the valves cannot be opened manually, since they are located inside the containment. However, procedure SDS-02 can be used to cross-tie power from an available DC train to the valve on the unavailable DC train. Multiple breaker isolations are made between the unavailable DC train and the ECCS vent valves before the cross-tie is connected. This assures that the available DC train is not directly connected to the unavailable DC train.

Recovery Factors ANO-2 added a special cross-tie operator during remainder of Cycle 14 to monitor the RCS depressurization cues following a trip and carry out any local actions needed to accomplish the procedure.

Base case timing data The timing data are shown in Table 1 and are based on job performance measures and simulator observations. The data for P1 and P2 are conservatively assessed assuming that there was no previous cue for warning of the need for opening the ECCS vent valves.

Table 1 Base Case Timing Data Symbol Description of Cue or Action Timing data Minutes Reference ts Total time from cue of CETs > 800 43.98 Most restrictive case for cues for F to hot gas circulation operator actions (MAAP) tP1 a Precise configuration detection 3 Observation of Simulator exercise and reporting by crew to SRO 6/20/00 Situation assessment by crew tP1 b considering all issues (e.g., Observation of Simulator exercise switching from prevention to 6/20/00 mitigation).

T1/2 (P2) Formulate response plan for Observation of Simulator exercise ECCS venting by crew 6/20/00 From time that SRO authorizes DC Job performance measurement memo tP3 bus bus crossover c

thatP3 connection to vernection tostime te 7.5 7d on timing from the authorization by the SRO, until SDS-02 was completed.

that ECCS vent vales are opened Verified by walkdown 6/21/00 The time period data in Table 1 were examined and converted into parameters needed for input to the HCR model as shown in Table 2. The value of a was selected for two cases: one with an annunicator alarm and one without (when DC bus 2D01 in unavailable during the accident).

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Table 2 manipulation of the time data for input to the HCR model Symbol Description of Cue or Action Timing data Minutes Reference ta Calculated available time (ta) for 25.48 HCR method treated as the time from response planning cue in time dependent cases Evaluation of normalized time 5.10 HCR method window = ta/Tl/2 Evaluation of type of cue CP3 CP3 = .75, or ORE data from simulator a unless D201 available for high CP2 = .57 measurements CET alarm at 700 F then CP2 Base case HEP data The base case evaluations of Pla and Plb cognitive errors are summarized in Table 3, below The evaluation of the various trees clearly indicates the ANO-2 plant staff has done a very good job in formulating procedures to minimize the possibility of cognitive errors by providing solid cues, clear steps and correct labeling for all interfaces. The basis for the P2 and P3 assessments are also provided in the table.

Table 3 Base case cognitive and implementation errors Symbol Type of Error HEP data or result Reference Evaluation of procedures From EPRI TR-100259. Sum 2203.01G and SDS-02 for standard estimates from Pca: branch Pla cognitive errors in detection using 0.006 a, Pcb: branch e, Pcc: branch b, trees a,b,c,d in TR-100259 Pcd: branch a Evaluation of procedures 2203.01G and SDS-02 for From EPRI TR-100259. Sum P1 b cognitive errors in situation standard estimates from Pce: branch 0.008 assessment using trees e,f,g, and c, Pcf: branch b, Pcg: branch g, Pch:

h in TR-1 00259 branch NA; 0.5 factor for extra watch Evaluation of HCR probability for P2 assuming a CP3 type of cue 0.0149 From EPRI TR-10025 1-D)(In(tn)/a))

From NUREG/CR-4772 (ASEP).

P3 Key data elements for assessing Two of three Annunciators .002, implementation errors. 0.006 Table 8-5 (3) =.02, STAR training self recovery =.2, P3=.002+.02*.2 Calculation for failure to open ECCS vent valves 0.0349 HEP= Pla+Plb+P2+P3 The base case result indicates that the HEP for this mitigation action goes below 0.04 when no additional PSFs are applied. This means that incorporation of the RCS depressurization action into plant procedures during the remainder of the ANO-2 Cycle 14 reduces the frequency of a SGTR prior to a hot leg failure by more than 90% if there was no chance of creep rupture before 45 minutes. The assumption of no rupture within 45 min after reaching 800 F on the CETs is probably quite uncertain, therefore better understanding of the HEP dependence and possible PSFs were examined in a timing assessment.

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HRA Timing Assessment The timing assessment uses the same basic inputs as the base case except that the ta parameter in tn is replaced with the time from the cue, making the calculation independent of the estimate of the time of creep rupture. A range of times are used to simulate the time it takes to open vent valves in the CR, with and without the need for locally powering the vent valve. It is no surprise that initially the HEP is 1.0 and only after all the standard time factors have been considered does the HEP value begin dropping to the residual of cognitive and implementation error probability.

The large initial delay is due to the time taken to perform detection, validation, situation assessments, and response planning. There were several cycles of these distinct phases during the simulation, and each has been very conservatively assessed for this action.

HEPcurves Table 4 also provides the results of these assessments; and, Figure 1 graphically depicts these results versus time after the last cue occurs.

The nominal case 1 applies to scenarios with only one DC bus available where CR operators can depressurize the RCS via local actions and assume no early warning cue CET high at 700 F.

The nominal case 2 applies to scenarios with both DC busses available where CR operators can open both vent valves from the CR to depressurize the RCS including an early warning cue CET high at 700 F.

The nominal case 3 applies to scenarios with both DC busses available where CR operators can open both vent valves from the CR to depressurize the RCS, but an early warning cue CET high at 700 F is not available.

In scenarios with both busses unavailable, or a mechanical failure of either valve in the closed position, it is assumed that no action can cause opening of the vent valves. These cases may or may not also include the lack of cues.

Thus, the selection of a case to apply to a cutset addresses electrical bus dependencies on the operation of the two vent valves that are in series on the vent line.

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Table 4 Summary of Time De endent HEP data for Depressurizing RCS after CETs reach 800 F Time after CET 1 Nominal with local 2 Nominal in CR with 3 Nominal in CR no cue (minutes) action (SDS-02) 21<07 Alarm 2K07 alarm 10 1.000 1.000 1.000 15 1.000 1.000 1.000 20 1.000 0.225 0.436 22.5 0.892 0.118 0.292 25 0.569 0.069 0.203 30 0.221 0.033 0.111 35 0 106 0.024 0.071 40 0.064 0.021 0.052 45 0.047 0.020 0.043 50 0.039 0.020 0.038 55 0.036 0.020 0.035 60 0.034 0.020 0.034 65 0.032 0.020 0.033 Figure 1 Summary of Time Dependent HEPs for Depressurizing RCS after CETs reach 800F Total HEP for mitigation of SG tube creep rupture potential versus time using ANO-2 Procedure 2203.012G cued by CET Indications (with and with out local action SDS-02 and Alarm 2K07) 1 000 0.900 0 800 CL

+ 0 700 C.

+

S0600

0.500 a.

I N 04500

0.400 0.200 0,100 0+000 10 20 30 40 50 60 Time In minutes from high CET cue Indications (five or more greater than 900 F)

The results in Table 4 illustrate the approximate time associated with an HEP of 0.25. In all cases, this time is expected to be in advance of the time of a SG tube creep rupture; these times are shaded in Table 4. Thus, a value of 0.25 for the probability of not opening the ECCS vent valves before SG tube creep rupture could be applied to all qualifying sequence frequencies.

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Attachment to 2CAN060018 Attachment 6 Loop Seal Discussion

RESPONSE TO NRC RAI, 6/29/2000 The ANO-2 MAAP results for the high/dry/low sequences with operator depressurization were reviewed to identify the condition of the core downcomer, the cold leg loop seals (RCP loop seals), and the presence of unidirectional flow patterns in the RCS piping. For each operator depressurization case, the review focused on the period between initiation of depressurization and hot leg creep rupture. The cases were found to behave in a similar fashion. This behavior is described below.

The RCS pressure drops rapidly when the operators open the vent valves, and then stabilizes when the SITs inject and the core water level recovers to the lower portion of the core. The downcomer becomes unblocked during the depressurization phase, and then becomes blocked again when the SITs discharge. For cases where the delay in depressurizing is long (45 minutes or infinite), the median hot leg failure time is earlier than the time the downcomer becomes unblocked. Unblocking the downcomer is due to flashing if the operators depressurize; if they don't, it is caused by debris relocation.

The cold leg loop seals never become unblocked in the MAAP model. The code inputs are set up to require that 2.1 cubic meters of water be present in each cold leg loop seal to prevent gas flow. At the end of the blowdown, 4 to 4.5 metric tons of water still remains per loop, i.e. about 2.7 cubic meters of water remain in each cold leg The flow patterns are consistent with the above conditions: counter-current flow drops nearly to zero over about a half hour period following depressurization, but a small counter-current flow continues. The unidirectional flow rates are large in the hot leg between the reactor vessel and the surge line and are negative elsewhere (i.e. the flow in both loops is toward the surge line rather than circulating as one would expect if the loop seals cleared and large loop flows initiated).

Attachment to 2CAN060018 Attachment 7 Comparison of Actual and Predicted Burst and Ligament Tearing Pressures

Predicted BP Ligament I Burst Pressure Structurally Structurally Framatome Tearing Significant SG Tube Room Significant Equation Pressure Room Length Depth Temperature SRoom Temp Temp 4147 3945 2468 0.906 85.8 B 72-72 85-67 3958 4802 3529 1.250 75.7 B

"70-98 3250 3356 1138 0.660 94.5 A

"16-56 3200 4446 3061 0.890 81.8 A

16-60 3975 3797 2415 1.038 85.3 B

4650 4845 3642 1.037 76.2 B 37-67 5000 5350 4274 0.756 74.1 A 82-118 8123 8384 N/A 0.270 55.4 B 96-116 9810 10097 N/A 0.210 39.9 B 19-55 Predicted BP Ligament Structurally Structurally Maximum Insitu Framatome Tearing Test Pressure Equation Significant Significant SG Tube Pressure Room Room Temp Room Length Depth Temp Temperature 4650 5887 N/A 1.077 66.6 B 23-55 4650 3850 N/A 1.161 84.8 B 102-110 4650 6330 N/A 0.866 63.9 B 36-36 4650 6024 N/A 0.482 72.4 B 33-71 4650 4643 N/A 0.590 83.2 B 53-83 4800 5279 N/A 0.540 78.3 B 8-116 4950 13259 N/A 0.132 2.2 B 3-147 4900 6720 N/A 0.280 73.8 B 9-117 4850 8138 N/A 0.180 66.0 B 11-129 4950 12323 N/A 0.066 22.0 B 14-136 4850 5194 N/A 0.328 86.5 B 23-65 4850 6494 N/A 0.432 68.9 B 34-70 4950 6209 N/A 0.530 69.5 A 48-70 4950 7176 N/A 0.366 64.5 A 60-88 4800 6379 N/A 0.548 67.2 B 63-77 4950 8962 N/A 0.570 43.0 A 74-98 For Room Temp Burst pressure avg mtl properties = 134 ksi For Oper Temp Burst pressure avg mtl properties = 144.5 ksiI The above values were calculated usin _a randomly selected value for material properties.

Using the Framatome equation previously provided with the average material properties above will give slightly different results.

I

The yield stress used for the calculation of leakage from tube 8-134 in the "B" SG was - 43 ksi.

v t e Letter Sequence Other
TAC:MA8418, (Open)
Initiation Acceptance... Administration Questions Answers Results Approval... Other: 2CAN060012, Unit 2 Additional Information on Proposed Risk-Informed License Change Regarding Steam Generator Tubing, 2CAN060018, Additional Information and Commitments Related to Proposed License Change for Cycle 14 Risk-Informed Operation, Diskette with ANO-2 MAAP Data Attached, ML003724403
MONTHYEAR2000-06-23 [Table View]

2CAN060018, Additional Information and Commitments Related to Proposed License Change for Cycle 14 Risk-Informed Operation, Diskette with ANO-2 MAAP Data Attached

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