ML20217B390

Forwards Questions Re Ceco Submittal of Revised SG Tube Rupture Analysis for Byron,Unit 1 & Braidwood,Unit 1

ML20217B390
Person / Time
Site:	Byron, Braidwood
Issue date:	09/23/1997
From:	Dick G NRC (Affiliation Not Assigned)
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
TAC-M97315, TAC-M97317, NUDOCS 9709240283
Download: ML20217B390 (9)

Text

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September 23, 1997 2

i MEMORANDUM T0:

Document Control Desk FROM:

George F. Dick, Jr., Senior Project Managed f'k

[j ( [ ' /6 Project Directorate III-2

/s Divisior of Reactor Projects III/IV Office of Nuclear Reactor Regulation

SUBJECT:

QUESTIONS FOR COMMONWEALTH EDISON REGARDING ITS SUBMITTAL 0F A REVISED STEAM GENERATOR TUBE RUPTURE ANALYSIS FOR BYRON, UNIT 1, AND BRAIDWOOD, UNIT 1 (TAC NOS. M97315 AND M97317)

Attached are questions regarding the subject submittal, which were developed to permit the NRC staff to model the conveyance and the release of radioactivity for the steam generator tube rupture, main steamline break, rod ejection, and locked rotor accidents as they apply to the replacement steam generators.

Please place the attachment in the public and local public document rooms.

Docket Numbers STN 50-454 and STN 50-456

Attachment:

As stated l (')

kdi.034 9709240283 970923 PDR ADOCK 05000454 P

PDR

Byron Questions The Byron submittals for the amendment to increase the RCS activity of dose equivalent *I and to replace the Westinghouse D4 SGs with B&W SGs have been reviewed. As a result of this review, it has been determined that there exists an insufficient amount of information to perform confirmatory calculations of the proposed action.

In order to com)lete this action, the licensee needs to provide information sufficient for ) ERB to model the conveyance and the release of radioactivity for the SGTR, MSLB rod ejection and locked rotor accidents.

If the replacement SGs have no impact at all on the releases of radioactivi_ty to the environment for any _of theee accidents, then data need not be provided for the accident involved.

Comed should supply the following information and any additional information that is necessary for the staff to accurately model the response of the replacement SGs.

For each of the accidents provide a time line for those aspects of the event relevant to the determination of releases to the environment.

1.

For the MSLB accident, provide the following information:

a.

Mass of liquid released from the faulted SG as a function of time; b.

Mass of steam released from the intact SG as a function of time. As a minimum, releases should be designated as those within two hours and those after two hours; c.

Flashing fraction for primary to secondary leakage into the intact SGs:

d.

Scrubbing fraction for flashed portion of primary to second ry leakage into the intact SGs; e.

Primary bypass fraction (liquid entrained in the flashing fraction) for intact SGs:

f.

Time to isolate faulted SG:

g.

Duration of plant cooldown by the secondary side.

h.

Additional information which should be provided is contained in the Attachment 1.

2.

For the SGTR accident, provide the following information:

a.

Mass of liquid and steam released from the faulted SG as a function of time: As a minimum. releases should be designated as though within two hours and those after two hours:

b.

Mass of steam released from the intact SG as a function of time.

As a minimum, releases should be designated as though within two hours and those after two hours; c.

Flashing fraction in the intact and faulted SGs:

d.

Scrubbing fraction in the intact and faulted SGs:

e.

Primary bypass fraction for the intact and faulted SGs; g.

Time to isolate faulted SG:

h.

Duration of plant cooldown by the secondary side; i.

Primary to secondary release rate from the ruptured tube as a function of time:

j.

Whether overfill conditions exist.

If they do, appropriate Enclosure

mass release data should be provided as a function of time for the faulted SG.

k.

Additional information which should be provided is contained in the Attachment 2, 3.

For the locked rotor accident, provide the following information:

a.

Liquid release from the SGs as a function of time; b.

Duration of plant cooldown by the secondary side:

c.

A description of how the primary to secondary releases were modeled as releases to the environment.

d.

Fraction of fuel rods experiencing cladding perforation and/or fuel melting 4.

Fortherodejectionaccident,hrovidethefollowinginformation:

a.

The fraction of the fuel rods which have their cladding breached as a result of this accident; b.

The fraction of the fuel rods which reach or exceed the initiation temperature for fuel melting as a result of this accident:

c.

For the release via the primary to secondary leakage pathway, a description of the assumptions which were utilized in the release of such activity.

d.

For the release via the containment pat Nay, a description of the assumptions which were utilized in the release of such activity.

s

INPUT PARAMETERS FOR EVALUATION OF MAIN STEAMLINE BREAK ACCIDENT 1.

Primary coolant concentration for TS's maximum instantaneous value 23 for dose equivalent 1.

Pre-existina Soike Value (uCi/a) 232 1 13: 1 133{

ml 13si 2.

Volume of primary coolant and secondary coolant.

3 Primary Coolant Volume (ft )

Primary Coolant Temperature ( F) 3 Secondary Coolant Steam Volume (ft )

Secondary Coolant Liquid Volume (ft )

Secondary Coolant 5 team Temperature ( F)

Secondary Coolant Feedwater Temperature ( F) 232 3.

TS limits for DE 1 in the primary and secondary coolant.

23 Primary Coolant DE I concentration 48 hour5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> TS value (pCi/g) 32 Secondary Coolant DE 1 concentration (pCi/g) 4.

TS value for the primary to secondary leak rate.

Primary to secondary leak rate, any SG (gpd)

Primary to secondary leak rate, total all SGs (qpd) 5.

Iodine Partition Factor Faulted SG 1

Intact SG 0.1 Primary to Secondary Leakage 1.0 6.

Steam Released to the environment Faulted SG (1bs) 0-2 hours

> 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> Intact SGs (lbs) 0-2 hours

> 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> 7.

Letdown Flow Rate (gpm)

8.

Release Rate for 48 hour5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> TS of Dose Equivalent 'il 2

Ci/hr 131 ;

tri 233 1 "I

135 ;

9.

Atmospheric Dispersion Factors EAB (0-2 hours)

LPZ (0-8 hours)

Control Room (0-8 hours)

10. Control Room 3

Volume (ft )

Normal Makeu) Flow (cfm)

Emergency Maceup Flow (cfm)

Makeup Filter efficiency (%)

Unfiltered Inleakage (cfm)

Recirculation Filter Flow Rate (cfm)

Recirculation Filter Efficiency (%)

MAIN STEAMLINE BREAK THYROID DOSE ASSESSMENT Ere-existina Soike EAB LPZ Control Room Calculated doses (rem)

Regulatory Guidelines 30 30 30 (rem)

Accident Initiated Soike EAB LPZ Control Room Calculated doses (rem)

Regulatory Guidelines 30 30 30 (rem)

C INPUT PARAMETERS FOR EVALUATION OF SGTR 32 1.

PrimarycoolantconcentrationofTSLvalue;fordoseequivalent 1.

Pre-existina Soike Value (uCi/a) 131 ;

132 1 233 1 2"I us; 2.

Volume of primary coolant and secondary coolant.

3 Primary Coolant Volume (ft )

Primary Coolant Temperature ( F) 3 Secondary Coolant Steam Volume Total (ft )

Secondary Coolant Mass Total (lbs)

Primary Coolant P essure (psia)

Primary Coolant Mass (lbs)

Pressurizer Volume (ft )

Pressurizer Temperature ( F)

Pressurizer Pressure (psia)

Secondary Coolant Liquid Mass /SG (lbs)

Secondary Coolant Steam Mass /SG (lbs)

Seccr,dary Steam Temperature ( F)

Secondary Liquid Temperature ("F) 3.

TS Limits for DE "2I in the primary and secondary coolants:

Maximum Instantaneous in primary coolant (pCi/g) 48 Hour DE in primary coolant (pCi/g)

Secondary Coolant (pCi/g) 4.

TS value for the primary to secondary leak rate (include reference temperature and pressure):

Any SG (gpd)

Total all SGs (gpm) 5.

Primary coolant activity (Ci) due to a pre-existing spike:

ul{

u2 5 "3 I lui us; 6.

Primary coolant activity levels (pC1/g) for accident initiated

..~

spike.

131 1 try 133 2"1..

I 135 1 7.

Primary cooljnt concentration at maximum instantaneous value of dose 2

equivalent I.

131 1 12 1 133 1 2"I iasi 8.

Primary Coolant Activity (C1) for Accident Initiated Spike lat i iri 133 ;

tui iasi 9.

Iodine Partition Factor Faulted SG Intact SG Condenser

10. Steam Released to the environment as a function of time:

Faulted SGs 0-2 hours

> 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> Intact SGs l

0-2 hours

> 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />

11. Letdown Flow Rate (gpm)

12. Atmospheric Dispersion Factors:

EAB (0-2 hours)

LPZ (0-8 hours)

Control Room (0-8 hours)

13. Control Room:

Emergency Makeup Flow (cfF.1 Makeup Filter efficiency i%)

Unfiltered Inleakage Nrm)

Recirculation Filter Flow Rate (cfm)

Recirculation Filter Efficiency (%)

i Occupancy Factor (0-1 day)

14. For the Accident Initiated Spike Case Release Rate (C1/hr) 500X Release Rate (Ci/hr) 131 }

132]

133{

• I 1

lasi i

15. Flashing Fraction. Primary Bypass and Scrubbing Fraction as a function of time.

16. Mass release rate through the ruptured tube as a function of time, i

j STEAM GENERATOR TUBE RUPTURE THYROID DOSE ASSESSMENT I-Case Involvina Pre-existina Soike EAB W

Control Room Calculated thyroid dose (rem)

Regulatory Limits (rem) 300 300 30 Case Involvino Accident Initiated Soike EAB W

Control Room Calculated thyroid dose (rem)

Regulatory Guidelines (rem) 30 30 30