ML030340171

Response to a Request for Additional Information in Support of License Amendment Request No. 300 & 172

ML030340171
Person / Time
Site:	Beaver Valley
Issue date:	01/30/2003
From:	Bezilla M FirstEnergy Nuclear Operating Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
L-03-007
Download: ML030340171 (54)

Text

FENOC Beaver Valley Power Station Route 168 "fm PO Box 4 FirstEnergy Nuclear Operating Company Shippingport, PA 15077-0004 Mark B. Bezilla 724-682-5234 Site Vice President Fax 724-643-8069 January 30, 2003 L-03-007 U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555-0001

Subject:

Beaver Valley Power Station, Unit No. 1 and No. 2 BV-1 Docket No. 50-334, License No. DPR-66 BV-2 Docket No. 50-412, License No. NPF-73 Response to a Request for Additional Information in Support of License Amendment Requests Nos. 300 and 172 This letter provides FirstEnergy Nuclear Operating Company (FENOC) responses to the Section 2.0 questions provided in the November 22, 2002 NRC Request for Additional Information (RAI) regarding License Amendment Requests (LAR) 300 and 172. The LARs were submitted by FENOC letter L-02-069 dated June 5, 2002.

The changes proposed by the LARs will revise the Beaver Valley Power Station (BVPS) Units 1 and 2 Technical Specifications to permit each unit to be operated with an atmospheric containment.

The responses to Section 2.0 of the November 22, 2002 RAI are provided in Attachment A of this letter. The response to RAI Item 2.0.5 references a drawing, a sketch and an input data file of meteorological data. The drawing, sketch and input data file are provided in Attachments B, C, and D, respectively.

Attachment E contains revisions to Figures 4.1-4 and 4.1-5 of the Containment Conversion Licensing Report, which was submitted in support of LARs 300 and 172.

The figure revisions correct inconsistencies contained in the figures previously submitted.

The condition that resulted in the need for these revisions was entered into the BVPS corrective action program and Attachment E includes a discussion of the condition and the cause.

The figure revisions contained in this transmittal have no impact on the proposed Technical Specification changes, or the no significant hazards consideration, transmitted by FENOC letter L-02-069.

As stated in Letter L-02-069, FENOC requests approval of the proposed amendments by July 15, 2003, to support implementation following the next scheduled refueling outage for Unit 2; i.e., 2R10.

1"0 0

Beaver Valley Power Station, Unit No. I and No. 2 License Amendment Request Nos. 300 and 172 L-03-007 Page 2 There are no commitments contained in this letter.

If there are any questions concerning this matter, please contact Mr. Larry R. Freeland, Manager, Regulatory Affairs/Performance Improvement at 724-682-5284.

I declare under penalty of perjury that the foregoing is true and correct. Executed on January.__, 2003.

Sincerely, Mark B.

Beaver Valley Power Station, Unit No. 1 and No. 2 License Amendment Request Nos. 300 and 172 L-03-007 Page 3 Attachments:

A.

Responses to RAI Section 2.0.

B.

Drawing Number 8700-RY-IC C.

Sketch Number 3CGKO0012 D.

Meteorological Data E.

Revised Containment Conversion Licensing Report Figures c:

Mr. D. S. Collins, NRR Project Manager Mr. D. M. Kern, NRC Sr. Resident Inspector Mr. H. J. Miller, NRC Region I Administrator Mr. D. A. Allard, Director BRP/DEP Mr. L. E. Ryan (BRP/DEP)

(w/o Attachment D)

(w/o Attachment D)

(w/o Attachment D)

(w/o Attachment D)

Attachment A to L-03-007 Responses to November 22, 2002 RAI Section 2.0 - Radiological Assessment NRC Request for Additional Information 2.0 Radiological Assessment Item 2.0.1 The text of the submittal states that the analyses were performed at a higher power level than BVPS-1 and 2 are currently licensed to operate at. This was apparently done to support a future power uprate. However, as the staff understands your submittal, only the LOCA and control rod ejection accident (CREA) analyses were done at this power level. The remaining analyses (offsite and control room) were performed at the currently licensed power level, and will need to be revised to support the future power uprate.

Please confirm the staff s understanding.

Response to Item 2.0.1 FirstEnergy Nuclear Operating Company (FENOC) confirms that only the loss-of coolant accident (LOCA) and the control rod ejection accident (CREA) site boundary and control room dose analyses were done at the uprate power level to support a future uprate. All of the remaining radiological assessments are intended to be applicable only at the current power level and will be revised later to support the future power uprate.

Item 2.0.2 On page 17, Section 4.0, there is a statement that the revised analyses were performed at a bounding future power uprate core power level of 2900 MWt.

Page 1-1 of the Licensing Report states an uprate to 2910 MWt. Additionally, there are several references to an analysis power level of 2918 MWt, which apparently includes the correction for measurement uncertainty. Please confirm that the LOCA and CREA were analyzed at the 2918 MWt power level.

Response to Item 2.0.2 FENOC confirms that the LOCA and the CREA were analyzed at a core power level of 2918 megawatts thermal (MWt). This analysis value is based on a planned extended power uprate, which will raise Rated Thermal Power (RTP) to 2900 MWt. The analysis value includes an allowance for a calorimetric power measurement uncertainty of 0.6%.

The 2910 MWt is the expected Nuclear Steam Supply System power level based on a RTP of 2900 MWt. The 2910 MWt accounts for the net heat input from the reactor coolant pumps. A License Amendment Request (LAR) for the extended power uprate is currently being prepared by FENOC.

Page 1 of 42

Attachment A (continued)

L-03-007 Item 2.0.3 The BVPS common control room is currently isolated by a containment isolation signal or a high radiation monitor signal. FENOC is proposing to eliminate the automatic isolation signal from the radiation monitor and, instead, rely on manual operator action triggered by the radiation monitor for the locked rotor accident. Although the dose calculations indicate that isolation may not be needed, the staff believes that this is a non-prudent reduction in defense-in-depth. The staff requests that FENOC justify this proposed change specifically addressing the guidance in Section 1.1.2 of Regulatory Guide (RG) 1.183 that "Modifications proposed for the facility generally should not create a need for compensatory activities, such as reliance on operator actions."

" Unlike many other reactors with Westinghouse solid state protection, BVPS-1 and 2 does not have a control room isolation actuated by a safety injection signal. With the proposed change, automatic isolation would occur only for LOCAs that cause containment (CNMT) pressures high enough to trigger containment isolation.

There would be no automatic isolation available for any other accident.

" The staff understands that there is not a dedicated main bench board annunciator window for the control room area radiation monitors, but rather, a generic window that signifies that a radiation monitor channel has alarmed.

At Unit 1, operators must leave the controls area to examine the radiation monitor racks to determine the channel in alarm.

Response to Item 2.0.3 Although the Radiation Monitoring System (RMS) automatic isolation signal was not credited in any of the new control room habitability analyses done to support the containment conversion and power uprate, at present FENOC has no plans to eliminate the automatic feature from the RMS design, nor to downgrade the control room monitor.

Instead, the proposed change is to eliminate Control Room Emergency Bottled Air Pressurization System (CREBAPS), and allow the containment isolation phase B (CIB) signal or the control room RMS monitor to initiate control room isolation and actuate the Control Room Emergency Ventilation System (CREVS) pressurization fans, without the 60 minute delay currently employed to provide time for the CREBAPS bottles to discharge. This is documented in Section 6.3.1.2 of the Licensing Report. The RMS signal initiating CREVS was retained to provide diversity.

Each control room area monitor has two alarms, the high alarm alerts the operator to the possibility of a radiological event in progress, and the high-high alarm actuates control room isolation and pressurization.

The potential need for manual operator action to Page 2 of 42

Attachment A (continued)

L-03-007 isolate and pressurize the control room is part of the current design basis for Beaver Valley Power Station (BVPS), and has been foreseen in licensed operator training and in the Emergency Operating Procedures (EOP). As such, the proposed amendments do not result in any new reliance on manual operator actions. The EOP task will be different, however, in that manual operator action in the future will be concerned with ensuring that a pressurization fan is running following control room isolation rather than after the CREBAPS bottles have discharged. This change is included in the planned changes to be implemented after NRC approval of the LARs. Refer to section 6.3.1 of the Containment Conversion Licensing Report for further discussion on operation of the CREVS pressurization fans.

In the current design, there are potentially two manual operator actions required in the event of a failure of the control room habitability systems to operate automatically; first to actuate CREBAPS, and then 60 minutes later to actuate CREVS.

The proposed change replaces these with one manual operator action, and in the analyzed event this occurs well before the conditions become potentially hazardous. Therefore, the proposed change is a net decrease in the need for manual operator action, and creates an improvement in radiological safety for the control room operators.

Moreover, since fewer components are in the actuation circuitry relied upon to perform this safety function, the proposed change results in a decrease in the risk of a failure.

The use of a safety injection (or CIA) signal to actuate CREVS instead of CIB has been considered by FENOC, but a decision to make this change has been deferred because the control room habitability analyses results for both containment conversion and power uprate are satisfactory without it.

The change would not provide any additional protection for a locked rotor accident, since no safety injection signal results from this event.

Item 2.0.4 Does the proposed cavitating venturi flow elements in the Unit 1 auxiliary feedwater (AFW) injection lines change the thermodynamic inputs to the MSLB and steam generator tube rupture accidents, warranting a re calculation of the radiological consequences of these accidents?

For example, are the steam flows affected?

Duration of tube uncovery affected?

Page 3 of 42

Attachment A (continued)

L-03-007 Response to Item 2.0.4 The proposed cavitating venturi flow elements in the Unit 1 Auxiliary Feedwater (AFW) injection lines will not change the thermo-hydraulic inputs to the Main Steamline Break (MSLB) or steam generator tube rupture dose calculations.

Consequently, the radiological consequences of the above accidents are not impacted by this design change.

Item 2.0.5 Page 5-3 of the licensing report identifies that updated control room atmospheric dispersion factors using the ARCON96 methodology were utilized. The submittal did not provide sufficient information for the staff to evaluate this change to your design basis. Please provide the following information:

a.

Unit 1 and Unit 2 release point and receptor configuration information (e.g., height, velocity, distances, direction, etc.), release mode (e.g., ground, elevated, surface), and meteorological sensor configuration, as input to ARCON96.

b.

A floppy disk containing the meteorological data input to ARCON96, in the ARCON96 input data format.

Response to Item 2.0.5

a.

BVPS Unit 1 and Unit 2 release point and receptor configuration information, release mode, and meteorological sensor configuration information, used as input to ARCON96, are provided in Tables 2.0.5-1 and 2.0.5-2 for BVPS Units 1 and 2, respectively. A drawing that provides the Site Postulated Release and Receptor Points on a plot plan of BVPS Units 1 and 2 (Drawing No. 8700-RY-1C, Rev. 1) is also provided as Attachment B. A second drawing (Sketch No. 3CGKO0012) that shows the BVPS Unit 1 and Unit 2 layouts in relation to the Emergency Response Facility (ERF) is provided as Attachment C.

b.

A Compact Disk (CD) containing the 1990-1994 BVPS on-site meteorological data input to ARCON96, in the ARCON96 input data format, is provided as Attachment D.

Page 4 of 42

Attachment A (continued)

L-03-007 Table 2.0.5-1 BVPS-1 ARCON96 Atmospheric Dispersion Factor Inputs Unit I Containment Edge Release Receptor ARCON96 Parameter Unit I CR Unit 2 CR Unit 2 Aux. Bldg.

Unit 1 Service ERF Normal ERF Edge Intake Intake NW Corner Bldg.

Intake Closest to Cont.

Meteorological Information:

Period of Meteorological Data 1990- 1994 1990- 1994 1990- 1994 1990- 1994 1990- 1994 1990- 1994 Lower Measurement Height (in) 10.7 10.7 10.7 10 7 10.7 10.7 Upper Measurement Height (m) 45 7 45.7 45.7 45.7 45 7 45.7 Wind Speed Units m/sec m/sec rn/sec m/sec in/sec in/sec Meteorological Data File Names arconbv met arconbv.met arconbv.met arconbv met arconbv.met arconbv.met Source Information:

Release Type ground ground ground ground ground ground Release Height (m) 0.15 3 6 0.0 9.5 0,0 0.0 Building Area (m')

1,600 1,600 1,600 1,600 1,600 1,600 Vertical Velocity (m/see) 0,0 0.0 0.0 0.0 0 0 0 0 Stack Flow (m3/sec) 00 0.0 00 00 0.0 0.0 Stack Radius (m) 0.0 0 0 0.0 0.0 0.0 0.0 Receptor Information:

Distance to Receptor (m) 54.0 74.7 98 5 24.7 498.0 475.0 Intake Height (m) 0 15 36 0.0 95 00 00 Elevation Difference (m) 0.0 0 0 0.0 0.0 0.0 0.0 Direction to Source (deg) 198 208 207 171 247 239 Default Information:

Surface Roughness Length (m) 0.20 0.20 0.20 0.20 0.20 0 20 Wind Direction Window (deg) 90 90 90 90 90 90 Minimum Wind Speed (m/sec) 0.5 0.5 0 5 0 5 0.5 0 5 Averaging Sector Width Constant 4 3 4.3 4.3 4.3 4 3 4.3 Initial Diffusion Coefficients (m) 6.83, 7.44 6 83, 7 44 6 83, 7 44 6.83, 7.44 6.83, 7 44 6 83, 7.44 Page 5 of 42

Attachment A (continued)

L-03-007 Table 2.0.5 Continued BVPS-1 ARCON96 Atmospheric Dispersion Factor Inputs Unit 1 Containment Top Release Receptor ARCON96 Parameter Unit I CR Unit 2 CR Unit 2 Aux. Bldg.

Unit I Service ERF Normal ERF Edge Intake Intake NW Corner Bldg.

Intake Closest to Cont.

Meteorological Information:

Period of Meteorological Data 1990- 1994 1990- 1994 1990- 1994 1990- 1994 1990- 1994 1990 - 1994 Lower Measurement Height (m) 10.7 10.7 10 7 10.7 10.7 10.7 Upper Measurement Height (m) 45.7 45 7 45 7 45 7 45.7 45.7 Wind Speed Units rn/sec in/sec m/sec mi/sec mi/sec rn/sec Meteorological Data File Names arconbv.met arconbv.met arconbv.met arconbv.met arconbv.met arconbv.met Source Information:

Release Type ground ground ground ground ground ground Release Height (m) 44.7 44.7 44.7 44.7 44 7 44 7 Building Area (m2) 1,600 1,600 1,600 1,600 1,600 1,600 Vertical Velocity (n/sec) 0 0 0.0 0 0 0 0 0 0 0 0 Stack Flow (m3/sec) 0 0 0.0 0.0 0.0 0.0 0.0 Stack Radius (m) 00 00 00 00 00 00 Receptor Information:

Distance to Receptor (m) 74 4 94.2 118.9 45 1 518 0 495 0 Intake Height (m) 0 15 3 6 19.3 9.5 0.0 0.0 Elevation Difference (m) 0 0 0.0 0 0 0 0 0 0 0.0 Direction to Source (deg) 195 202 207 171 247 239 Default Information:

Surface Roughness Length (m) 0.20 0.20 0.20 0.20 0.20 0.20 Wind Direction Window (degrees) 90 90 90 90 90 90 Minimum Wind Speed (m/see) 0 5 0.5 0 5 0 5 0.5 0.5 Averaging Sector Width Constant 4.3 4.3 4.3 4.3 4.3 4 3 Initial Diffusion Coefficients (m) 0 0, 0.0 0.0, 0.0 0.0, 0 0 00, 0.0 0 0, 0 0 0 0, 0 0 Page 6 of 42

Attachment A (continued)

L-03-007 Table 2.0.5 Continued BVPS-I ARCON96 Atmospheric Dispersion Factor Inputs Unit I RWST Vent Release Receptor ARCON96 Parameter Unit 1 CR Unit 2 CR Unit 2 Aux. Bldg.

Unit 1 Service ERF Normal ERF Edge Intake Intake NW Corner Bldg.

Intake Closest to Cont.

Meteorological Information:

Period of Meteorological Data 1990- 1994 1990- 1994 1990- 1994 1990- 1994 1990- 1994 1990- 1994 Lower Measurement Height (m) 10.7 10.7 10.7 107 10.7 10.7 Upper Measurement Height (m) 45.7 45.7 45.7 45.7 45 7 45.7 Wind Speed Units m/sec m/sec m/sec m/sec rn/sec mn/sec Meteorological Data File Names arconbv.met arconbv.met arconbv.met arconbv.met arconbv met arconbv.met Source Information:

Release Type ground ground ground ground ground ground Release Height (m)

• 0.15 3 6 0 0 9.5 0.0 0.0 Building Area (m2) 1,600 1,600 1,600 0.0 1,600 1,600 Vertical Velocity (m/sec) 0.0 0 0 0 0 0.0 0.0 0.0 Stack Flow (m3/sec) 0.0 0.0 0.0 00 00 0.0 Stack Radius (m) 0 0 0 0 0.0 0.0 0.0 0 0 Receptor Information:

Distance to Receptor (m) 88 4 111 3 136.6 50.0 5500 5240 Intake Height (m) 0.15 3 6 0 0 9.5 0.0 0.0 Elevation Difference (m) 0.0 0.0 0 0 0 0 0 0 0 0 Direction to Source (deg) 218 221 221 213 249 241 Default Information:

Surface Roughness Length (m) 0.20 0.20 0.20 0 20 0.20 0.20 Wind Direction Window (degrees) 90 90 90 90 90 90 Minimum Wind Speed (m/sec) 0.5 0.5 0.5 0.5 0 5 0.5 Averaging Sector Width Constant 4.3 4 3 4.3 4.3 4.3 4 3 Initial Diffusion Coefficients (m) 0.0, 0.0 0 0, 0.0 0.0, 0 0 0 0, 0 0 0.0, 0 0 00, 0.0 RWST vent release height conservatively set equal to the receptor height or ground level Page 7 of 42

Attachment A (continued)

L-03-007 Table 2.0.5 Continued BVPS-1 ARCON96 Atmospheric Dispersion Factor Inputs Unit 1 Main Steam Relief Valve Release Receptor Unit I CR Unit 2 CR Unit 2 Aux. Bldg.

Unit 1 Service ERF Normal ERF Edge Intake Intake NW Corner Bidg.

Intake Closest to Cont.

Meteorological Information:

Penod of Meteorological Data 1990- 1994 1990- 1994 N/A N/A N/A N/A Lower Measurement Height (m) 10.7 10.7 N/A N/A N/A N/A Upper Measurement Height (m) 45.7 45.7 N/A N/A N/A N/A Wind Speed Units m/sec m/sec N/A N/A N/A N/A Meteorological Data File Names arconbv.met arconbvmet N/A N/A N/A N/A Source Information Release Type ground ground N/A N/A N/A N/A Release Height (m) 23 0 23.0 N/A N/A N/A N/A Building Area (m')

1,600 1,600 N/A N/A N/A N/A Vertical Velocity (m/sec) 0 0 0.0 N/A N/A N/A N/A Stack Flow (m3/sec) 0.0 0.0 N/A N/A N/A N/A Stack Radius (m) 0.0 0 0 Receptor Information:

Distance to Receptor (m) 64.0 86.3 N/A N/A N/A N/A Intake Height (m) 0.15 3.6 N/A N/A N/A N/A Elevation Difference (m) 0.0 00 N/A N/A N/A N/A Direction to Source (deg) 210 216 N/A N/A N/A N/A Default Information:

Surface Roughness Length (m) 0.20 0.20 N/A N/A N/A N/A Wind Direction Window (degrees) 90 90 N/A N/A N/A N/A Minimum Wind Speed (m/sec) 0 5 0.5 N/A N/A N/A N/A Averaging Sector Width Constant 4 3 4.3 N/A N/A N/A N/A Initial Diffusion Coefficients (m) 0.0, 0.0 0.0, 0.0 N/A N/A N/A N/A Page 8 of 42

Attachment A (continued)

L-03-007 Table 2.0.5-2 BVPS-2 ARCON96 Atmospheric Dispersion Factor Inputs Unit 2 Containment Edge Release Page 9 of 42 Receptor ARCON96 Parameter Unit I CR Unit 2 CR Unit 2 Aux. Bldg.

Unit 1 Service ERF Normal ERF Edge Intake Intake NW Corner Bldg.

Intake Closest to Cont.

Meteorological Information:

Period of Meteorological Data 1990- 1994 1990- 1994 1990- 1994 1990- 1994 1990- 1994 1990- 1994 Lower Measurement Height (m) 10.7 107 10.7 107 10.7 10.7 Upper Measurement Height (in) 45.7 45.7 45.7 45.7 45.7 45 7 Wind Speed Units m/sec m/sec m/sec rn/sec rn/sec m/sec Meteorological Data File Names arconbv.met arconbv.met arconbv.met arconbv.met arconbv.met arconbv.met Source Information:

Release Type ground ground ground ground ground ground Release Height (m) 0.15 3 6 0.0 9.5 0.0 0 0 Building Area (m')

1,600 1,600 1,600 1,600 1,600 1,600 Vertical Velocity (m/sec) 0.0 0 0 0 0 0 0 0.0 0 0 Stack Flow (mr/sec) 0 0 0.0 0.0 0.0 0.0 0.0 Stack Radius (m) 00 00 00 00 0.0 0.0 Receptor Information:

Distance to Receptor (in) 95.4 71.9 44.2 133 2 357.0 315.0 Intake Height (m) 0.15 3 6 0.0 9.5 0 0 00 Elevation Difference (m) 00 00 00 0.0 0.0 0.0 Direction to Source (deg) 47 45 49 46 262 252 Default Information:

Surface Roughness Length (in) 0.20 0.20 0.20 0.20 0 20 0 20 Wind Direction Window (deg) 90 90 90 90 90 90 Minimum Wind Speed (m/sec) 0.5 0.5 0 5 0.5 0.5 0 5 Averaging Sector Width Constant 4.3 4.3 4 3 4.3 4.3 4.3 Initial Diffusion Coefficients (in) 6.83, 7.44 6.83, 7.44 6.83, 7.44 6.83, 7 44 6 83, 7 44 6.83, 7 44

Attachment A (continued)

L-03-007 Table 2.0.5 Continued BVPS-2 ARCON96 Atmospheric Dispersion Factor Inputs Unit 2 Containment Top Release Receptor ARCON96 Parameter Unit I CR Unit 2 CR Unit 2 Aux. Bldg.

Unit I Service ERF Normal ERF Edge Intake Intake NW Corner Bldg.

Intake Closest to Cont.

Meteorological Information:

Period of Meteorological Data 1990- 1994 1990- 1994 1990- 1994 1990- 1994 1990- 1994 1990- 1994 Lower Measurement Height (m) 10.7 10 7 10.7 10.7 10.7 107 Upper Measurement Height (m) 45.7 45.7 45.7 45.7 45.7 45.7 Wind Speed Units rn/sec m/sec m/sec m/sec in/sec m/sec Meteorological Data File Names arconbv.met arconbv.met arconbv.met arconbv met arconbv.met arconbv.met Source Information:

Release Type ground ground ground ground ground ground Release Height (m) 44.7 44.7 44.7 44.7 44.7 44.7 Building Area (m2) 1,600 1,600 1,600 1,600 1,600 1,600 Vertical Velocity (mi/sec) 0.0 0 0 0.0 0.0 0.0 0.0 Stack Flow (m3/sec) 0.0 0.0 0.0 0.0 0 0 0.0 Stack Radius (m) 0 0 0 0 0.0 0.0 0.0 0 0 Receptor Information:

Distance to Receptor (m) 116.1 92.7 64 9 153.6 377.0 335.0 Intake Height (m) 0.15 3.6 19.3 9 5 0.0 0 0 Elevation Difference (m) 0.0 0 0 0 0 0.0 0.0 0.0 Direction to Source (deg) 47 45 49 46 262 252 Default Information:

Surface Roughness Length (m) 0.20 0.20 0.20 0.20 0.20 0.20 Wind Direction Window (degrees) 90 90 90 90 90 90 Minimum Wind Speed (m/sec) 0 5 0.5 0.5 0.5 0.5 0.5 Averaging Sector Width Constant 4.3 4.3 4.3 4 3 4.3 4.3 Initial Diffusion Coefficients (m) 0.0, 0 0 0.0, 0.0 0.0, 0.0 0 0, 00 0 0, 00 0 0, 0 0 Page 10 of 42

Attachment A (continued)

L-03-007 Table 2.0.5 Continued BVPS-2 ARCON96 Atmospheric Dispersion Factor Inputs Unit 2 RWST Vent Release Receptor Parameter Unit 1 CR Unit 2 CR Unit 2 Aux. Bldg.

Unit 1 Service ERF Normal ERF Edge Intake Intake NW Corner Bldg.

Intake Closest to Cont.

Meteorological Information:

Period of Meteorological Data 1990- 1994 1990 - 1994 1990- 1994 1990- 1994 1990 - 1994 1990- 1994 Lower Measurement Height (m) 10.7 10.7 10.7 10.7 10.7 107 Upper Measurement Height (m) 45.7 45.7 45.7 45.7 45.7 45.7 Wind Speed Units m/sec m/sec m/sec m/sec m/sec m/sec Meteorological Data File Names arconbv.met arconbv.met arconbv met arconbv.met arconbv.met arconbv.met Source Information:

Release Type ground ground ground ground ground ground Release Height (m)

• 0.15 3.6 0.0 9.5 0.0 0 0 Building Area (mi) 1,600 1,600 1,600 1,600 00 00 Vertical Velocity (m/sec) 0 0 0 0 0.0 0.0 0.0 0.0 Stack Flow (m3/sec) 0.0 0.0 00 00 0.0 0.0 Stack Radius (i) 0.0 0 0 0 0 0.0 0.0 0.0 Receptor Information:

Distance to Receptor (m) 164.3 140.8 112.2 201.5 336 0 291.0 Intake Height (m) 0.15 3.6 0.0 9.5 00 00 Elevation Difference (m) 0.0 0,0 00 00 0.0 0.0 Direction to Source (deg) 48 48 49 47 267 256 Default Information:

Surface Roughness Length (m) 0.20 0.20 0.20 0.20 0.20 0.20 Wind Direction Window (degrees) 90 90 90 90 90 90 Minimum Wind Speed (m/see) 0.5 0.5 0 5 0.5 0.5 0.5 Averaging Sector Width Constant 4.3 4.3 4.3 4.3 4.3 4 3 Initial Diffusion Coefficients (m) 0.0, 0 0 0 0, 0.0 0 0, 0.0 0.0, 0.0 0.0, 0.0 0.0, 0.0 RWST vent release height conservatively set equal to the receptor height or ground level.

Page 11 of 42

Attachment A (continued)

L-03-007 Table 2.0.5 Continued BVPS-2 ARCON96 Atmospheric Dispersion Factor Inputs Unit 2 Main Steam Relief Valve Release Receptor Unit I CR Unit 2 CR Unit 2 Aux. Bldg.

Unit 1 Service ERF Normal ERF Edge Intake Intake NW Corner Bldg.

Intake Closest to Cont.

Meteorological Information:

Period of Meteorological Data 1990 - 1994 1990 - 1994 N/A N/A N/A N/A Lower Measurement Height (m) 10.7 10.7 N/A N/A N/A N/A Upper Measurement Height (m) 45.7 45.7 N/A N/A N/A N/A Wind Speed Units m/sec m/sec N/A N/A N/A N/A Meteorological Data File Names arconbv.met arconbv.met N/A N/A N/A N/A Source Information Release Type ground ground N/A N/A N/A N/A Release Height (m) 23.0 23.0 N/A N/A N/A N/A Building Area (m')

1,600 1,600 N/A N/A N/A N/A Vertical Velocity (m/sec) 00 0.0 N/A N/A N/A N/A Stack Flow (m3/sec) 0.0 0 0 N/A N/A N/A N/A Stack Radius (m) 0 0 0.0 Receptor Information:

Distance to Receptor (m) 116.1 91.4 N/A N/A N/A N/A Intake Height (m) 0.15 3.6 N/A N/A N/A N/A Elevation Difference (m) 0.0 0.0 N/A N/A N/A N/A Direction to Source (deg) 57 59 N/A N/A N/A N/A Default Information:

Surface Roughness Length (m) 0.20 0.20 N/A N/A N/A N/A Wind Direction Window (degrees) 90 90 N/A N/A N/A N/A Minimum Wind Speed (m/sec) 0.5 0.5 N/A N/A N/A N/A Averaging Sector Width Constant 4.3 4.3 N/A N/A N/A N/A Initial Diffusion Coefficients (m) 0.0, 0.0 0 0, 0.0 N/A N/A N/A N/A Page 12 of 42

Attachment A (continued)

L-03-007 Item 2.0.6 Page 5-7 (and page 5-43) of the licensing report states that the MSLB and locked rotor accident (LRA) were assessed using existing licensing basis methodology/assumptions.

However, the submittal does not tabulate the assumptions as was done for the LOCA and CREA.

Please provide a tabulation of the assumptions and inputs (in particular, steam releases, steam generator masses, T/S and accident induced (alternate repair criteria) primary-to-secondary leak rates, credit for mitigation, etc.) used in assessing the impact on the control room dose of eliminating the automatic initiation of CREBAPS/CREVS via radiation monitors for the MSLB and LRA accidents. If this information has been previously docketed, please provide a specific reference.

Response to Item 2.0.6 The assumptions and inputs utilized in the existing licensing basis analyses for the MSLB and the LRA dose analyses supporting BVPS-1 and BVPS-2 are summarized in LARs 280 (Unit 1) and 151 (Unit 2), submitted to NRC via FENOC letter L-00-008, May 12, 2000, and LAR 284 (Unit 1), submitted to NRC via FENOC letter L-00-085, July 21, 2000. NRC acceptance of these LARs is documented in the NRC Safety Evaluation Reports (SER) attached to Amendment 237 (Unit 1) and Amendment 119 (Unit 2), issued March 22, 2001, and Amendment 236 (Unit 1), issued March 12, 2001.

Item 2.0.7 Page 5-7 through 5-9 addresses the impact on environmental qualification (EQ) doses and vital area access.

Please identify whether or not these discussions were based on the 2918 MWt power level?

Response to Item 2.0.7 FENOC confirms that the environmental qualification (EQ) and vital area access dose assessments are intended to be applicable only at the current licensed power level of 2689 MWt. As discussed on pages 5-8 and 5-9 of the Licensing Report, the only impact on environmental qualification (EQ) and vital area access dose assessments due to containment conversion was the increased duration of containment leakage.

This additional source was developed using Alternative Source Term (AST) assumptions at the uprated power level and added to the existing dose estimates, which are based on TID 14844 at the current licensed power level.

Page 13 of 42

Attachment A (continued)

L-03-007 Item 2.0.8 On Page 5-31 of the licensing report, it appears that containment sprays are not effective until 722 seconds, or about 12 minutes. Please explain the basis of this delay. If sprays are effective prior to this, please provide flow rate and droplet radius information for the earlier time period.

Response to Item 2.0.8 The quench spray starts approximately 89 seconds after accident. For purposes of model simplification and conservatism, no credit is taken for aerosol removal by quench or recirculation sprays until the recirculation spray is effective at 722 seconds after accident.

The spray flow rates provided on Page 5-31 of the Licensing Report represents the total flow rate due to quench and recirculation sprays.

Item 2.0.9 On Page 5-32 of the licensing report, it is stated that the steam condensation rates used by SWNAUA were calculated using the LOCTIC code.

However, the containment performance analyses were performed using MAAP. Please explain why MAAP was not used for this purpose and the sensitivity of the SWNAUA results to the differences between LOCTIC and MAAP.

Specify which code will be the licensing basis code for radiological analyses.

Response to Item 2.0.9 The LOCTIC code was utilized to calculate the input parameters (e.g., pressure, temperature, and steam condensation rates), which serve as input to SWNAUA for the aerosol removal coefficient calculation for the NUREG-1465 scenario. The LOCTIC computer code calculates higher pressure and temperature values and lower steam condensation rates when compared to MAAP5.

This is conservative for determining fission product removal.

The LOCTIC code will be the licensing basis code for radiological analyses.

Item 2.0.10 On Page 5-41 of the licensing report, the source term for the CREA is discussed. The first half of this paragraph is valid, however, the paragraph goes on to address gap fractions from Table 3 of RG 1.183. The latter portion of this paragraph appears to be irrelevant to the CREA analysis.

Please explain.

Response to Item 2.0.10 The latter portion of this paragraph was inadvertently included in the LAR. FENOC agrees that it is irrelevant to the CREA analysis.

Page 14 of 42

Attachment A (continued)

L-03-007 Item 2.0.11 For both the Unit 1 and Unit 2 MSLB discussions, a brief reference is made to the development of a scaling factor. The development and use of these factors is not clear.

Please explain how this scaling was done. Please include in the explanation how time-dependent changes in parameters (release rate, co-incident iodine spike, intake prior to 30 minutes vs. intake after 30 minutes, X/Q changes) are incorporated in the scaling factor development and use.

Response to Item 2.0.11 It is recognized that a simple scaling factor approach based on volumes will not necessarily yield conservative results, because of the time-dependent non-linear nature of the problem. However, for this application it was judged to be acceptable based upon qualitative knowledge of the time-dependent release and intake rates.

Provided below is a discussion of the methodology utilized to develop the control room dose scaling factor for the BVPS Unit 1 MSLB to reflect the elimination of the Control Room Emergency Bottle Air Pressurization System (CREBAPS). The control room dose scaling factor for the BVPS Unit 2 MSLB was developed using the same methodology but with BVPS Unit 2 input parameters.

Due to the similarity in approach, the development of the BVPS Unit 2 MSLB dose scaling factors are not specifically discussed in this response.

The current BVPS Units 1 and 2 MSLB control room dose estimates are based on manual initialization of the CREBAPS at 30 minutes after the accident. In the current design basis, the CREBAPS supplies the required pressurization air for 60 minutes after initiation. At T= 90 minutes, the control room is switched to the CREVS mode, during which the intake air utilized for control room pressurization is filtered with an effective removal efficiency of 97% for the iodine species. The control room is purged when the activity release due to a MSLB is terminated at T= 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />.

The scaling factor was developed to assess the impact on the calculated control room doses when the CREBAPS is eliminated, i.e., the 60 minute CREBAPS operation is replaced by the CREVS operation and a pressurized control room is assumed to be available at T= 30 minutes after the MSLB, and maintained until the activity release is terminated at T= 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />.

(1)

Current control room analysis parameters/dose consequences (i.e., prior to the proposed design modification of elimination of CREBAPS):

T = 0 - 30 minute (Normal operation)

Unfiltered intake

= 500 cfm Filtered intake

= 0 cfm Exhaust

= 500 cfm Page 15 of 42

Attachment A (continued)

L-03-007

" T = 30 - 90 minute (CREBAPS operation)

Unfiltered intake

= 10 cfm Filtered intake

= 0 cfm Exhaust

= 10 cfm

" T = 90 minute - 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> (CREVS operation)

Unfiltered intake Filtered intake Filtered efficiency Exhaust

= 10 cfm

= 1030 cfm

= 0.97 for iodine,

= 1040 cfm 0.0 for noble gas 0 T = 8 - 8.5 hour5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> (Post-release nuree)

Unfiltered intake Filtered intake Exhaust

= 28,000 cfm

= 0 cfm

= 28,000 cfm T = 8.5 hour-30 day (Normal operation)

Unfiltered intake Filtered intake Exhaust

• x/O value 0- 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />

= 2.43 E-03 s/mr3

• Calculated control room Co-incident Spike doses Thyroid Committed Dose Equivalent (CDE)

External Effective Dose Equivalent (EDE)

Skin Dose Equivalent (DE)

Co-incident spiking duration

• Calculated control room Pre-incident Spike doses Thyroid CDE External EDE Skin DE

= 21.4 rem

= 0.00187 rem

= 0.0345 rem

= 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />

= 10.4 rem

= 0.000625 rem

= 0.0172 rem Page 16 of 42

= 500 cfm

= 0 cfm

= 500 cfm

Attachment A (continued)

L-03-007 (2)

Development of the Thyroid Dose Scaling Factor:

Review of the current control room doses listed above indicates that the thyroid dose is the limiting dose (80% of the regulatory dose limit of 30 rem for the co-incident spike case, 35% of the regulatory dose limit for the pre-incident spike case).

The external EDE dose and the skin DE dose are approximately three orders of magnitude less than the regulatory limits of 5 rem whole body and 30 rem beta skin. It is therefore concluded that the external EDE dose and the skin DE dose will continue to remain insignificant following the proposed design change of CREBAPS elimination.

The control room thyroid dose depends on the amount of intake of iodine into the control room and the depletion rate of the iodine activity existing in the room. Since the activity release period is 0 -

8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> and the x/Q value remains unchanged during this time period, the iodine intake into the control room is a function of activity release rate, intake flow rate, filter efficiency and the unfiltered inleakage rate. It is also noted that during the co-incident spiking period (0 - 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />), the activity release from the faulted steam generator increases as a function of time after the accident.

For the purposes of this assessment, the activity release rate during a time period is represented approximately by the value at the mid-point of that time period. The only depletion mechanism of the iodine activity in the control room is the exhausting of the air and the decay. The intake activity with CREBAPS operation and the intake activity without CREBAPS operation are calculated and compared, and a conservative scaling factor derived. This scaling factor is applied to the pre-modification thyroid dose to obtain an approximate upper bound value for the case that the CREBAPS operation is replaced by the CREVS operation.

The BVPS-1 MSLB thyroid CDE scaling factor for the co-incident iodine spike is calculated in Table 2.0.11-1. The thyroid CDE scaling factor for the pre-incident iodine spike is calculated in Table 2.0.11-2.

Page 17 of 42

Attachment A (continued)

L-03-007 Table 2.0.11-1 BVPS-1 MSLB Thyroid CDE Scaling Factor for Co-incident Iodine Spike Original design No CREBAPS Comment with CREBAPS operation/

operation (Replaced by CREVS operation)

T = 0- 30 min (Tae = 0.25 hr)

Unfiltered Intake rate 500 cfm 500 cfm Filtered intake rate 0 cfm 0 cfm Co-incident spiking factor 0 25/4 = 0.0625 0.25/4 = 0 0625 Normalized to 4 hr value Exhaust rate 500 cfm 500 cfm Effective Intake 937.5 cf 937 5 cf T = 30 - 90 min (Tave = I hr)

Unfiltered Intake rate 10 cfm 10 cfm Filtered intake rate 0 cfm 1030 cfm Filter efficiency 0.97 Co-incident spiking factor 1/4 = 0.25 1/4 = 0 25 Normalized to 4 hr value Exhaust rate 10 cfm 1040 cfm Faster depletion, conservatively ignored Effective Intake 150 cf 613 5 cf T = 1.5 - 4 hr (T.,s = 2.75 hr)

Unfiltered Intake rate 10 cfm 10 cfm Filtered intake rate 1030 cfm 1030 cfm Filter efficiency 0 97 0 97 Co-incident spiking factor 2 75/4 = 0 6875 2.75/4 = 0 6875 Normalized to 4 hr value Exhaust rate 1040 cfm 1040 cfm Effective Intake 4218 cf 4218 cf T = 4-8 hr Unfiltered Intake rate 10 cfm 10 cfm Filtered intake rate 1030 cfm 1030 cfm Filter efficiency 0 97 0 97 Co-incident spiking factor 1

1 Spiking terminates at 4 hr Exhaust rate 1040 cfm 1040 cfm Effective Intake 9816 cf 9816 cf Total Effective Intake 15,100 cf 15,600 cf Scaling Factor =1.033 Page 18 of 42

Attachment A (continued)

L-03-007 Table 2.0.11-2 BVPS-1 MSLB Thyroid CDE Scaling Factor for Pre-incident Iodine Spike Original design No CREBAPS Comment iNith CREBAPS operation/

operation (Replaced by CREVS operation)

T = 0- 30 min Unfiltered Intake rate 500 cfm 500 cfm Filtered intake rate 0 cfm 0 cfm Exhaust rate 500 cfm 500 cfm Effective Intake 15,000 cf 15,000 cf T=30-90min Unfiltered Intake rate 10 cfm 10 cfm Filtered intake rate 0 cfm 1030 cfm Filter efficiency 0 97 Exhaust rate 10 cfm 1040 cfm Faster depletion, conservatively ignored Effective Intake 600 cf 2454 cf T =15 - 8 hr Unfiltered Intake rate 10 cfm 10 cfm Filtered intake rate 1030 cfm 1030 cfm Filter efficiency 0.97 0 97 Exhaust rate 1040 cfm 1040 cfm Effective Intake 15,951 cf 15,951 cf Total Effective Intake 31,551 cf 33,405 cf Scaling Factor =1.06 Page 19 of 42

Attachment A (continued)

L-03-007 (3)

Application of Scaling Factor:

"* Co-incident iodine spike - The original calculated total control room thyroid CDE, 21.4 rem, consists of 19.3 rem from the primary-to-secondary leak source released from the faulted steam generator (FRC Source), 2.06 rem from the faulted steam generator liquid initial activity release (FLI Source), and other insignificant doses from miscellaneous release sources. The scaling factor (1.033) calculated in Table 2.0.11-1, is applicable for the FRC source, and conservative for the FLI source. The scaling factor was conservatively applied to the total dose to obtain an upper bound value of 22.1 rem for the case that the CREBAPS operation is replaced by the CREVS operation.

" Pre-incident iodine spike - The original calculated total control room thyroid CDE, 10.4 rem, consists of 8.2 rem from the primary-to-secondary leak source released from the faulted steam generator (FRP Source), 2.06 rem from the faulted steam generator liquid initial activity release (FLI Source), and other insignificant doses from miscellaneous release sources.

The scaling factor (1.06) calculated in Table 2.0.11-2, is applicable for the FRP source, and conservative for the FLI source. The scaling factor was conservatively applied to the total dose to obtain an upper bound value of 11.0 rem for the case that the CREBAPS operation is replaced by the CREVS operation.

(4)

Acceptability of the Scaling Factors The scaling factors calculated in Tables 2.0.11-1 and 2.0.11-2 are based on comparison of the effective control room intake volumes during four critical time intervals (relative to either activity release or control room intake), with CREBAPS operation and without CREBAPS operation. In addition, the scaling factors ignore the increased exhaust rate from 10 cfm to 1040 cfm during T=30 minute to 90 minute (when the CREBAPS operation is replaced by the CREVS operation) and treat all intake activity with the same weight.

Since the major thyroid dose contributing isotope, 1-131, has a half-life of 8 days and the radioactive decay during the 0-8 hour MSLB accident period is not significant, the calculated effective intake volume also represent the 1-131 intake activity during the four time periods with and without the CREBAPS operation.

For a given intake activity, the control room thyroid dose depends on the integrated concentration resulting from the intake activity.

The integrated concentration is a function of the control room exhaust rate and the decay constant. Again, due to the long half-life of 1-131, the decay effect can be ignored in evaluating the impact on the integrated concentration for the activity intake during each of the four time intervals.

Consequently, the thyroid dose weighting factor for each intake interval depends on subsequent time dependent exhaust rate.

Page 20 of 42

Attachment A (continued)

L-03-007 To demonstrate the acceptability of the simplified scaling factor approach utilized in this application, a quantitative evaluation of the thyroid dose weighting factors for the activity intake during each of the four time intervals is provided below:

If V is the control room volume (fM3), f is the control room exhaust rate (cfm) and X. is the decay constant (min-1), then the activity concentration at time t minutes after the intake of 1 Ci is e

-(A+fl)t Ci/fl3 V

The integrated concentration for an intake of V Ci is Se-(A+fIl)l dt Ci-minl 3

If the exhaust flow remains constant and goes to infinity, the integrated concentration becomes 1

Ci-min/ft3 (2+ f /V)

In the case of long half-life isotopes or/and high exhaust rates, the radioactive decay is insignificant and the integrated concentration varies approximately in inverse proportion to the exhaust rate.

Now, for an intake activity that has been depleted at an exhaust rate of f0 cfm for To minutes, the integrated concentration during time TO to TI minutes at an exhaust rate of fl cfm is (ignoring the decay effect)

V e(foV)To (1-e-(fIV)(TI*To)

)

Ci-min/fl3 f,

It is recognized that the factor e-(fo/V)To represents the reduction factor due to depletion prior to the dose contributing interval and the rest is the integrating factor during that time interval.

The thyroid dose weighting factors for the co-incident iodine spike are calculated below (control room V = 173,000 ft3). The weighting factor is defined as the ratio of the integrated concentration of that interval (see equation above) to the integrated concentration corresponding to an exhaust rate of 1040 cfm, no prior depletion, and infinite integration time. Note that the control room is purged at T=8 hours, and the dose contribution after 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> is not significant in evaluating the weighting factors.

Page 21 of 42

Attachment A (continued)

L-03-007 (The weighting factor is normalized to the value corresponding to fl = 1040 cfm, To= 0, & TI= c)

Intake Time Interval 4-8 hr 1.5-4 hr 0.5-1.5 hr 0 - 0.5 hr (Tave=6 hr)

(Tave=2 75 hr)

(Tave=l hr)

(Tave=0.25 hr) 0-0.5 hr To (mm) 0 fo (cfm) 0 TI -To (min) 15 fl (cfm) 500 weighting factor 0.088 0.5-1.5 hr To (min) 0 15 fo (cfm) 0 500 TI -To (mm) 30 60

_ fl (cfm) 10 10

_ weighting factor 0.180 0.345 1.5-4 hr To (min) 0 30 15/60

_fo (cfm) 0 10 500/10

_TI

- To (min) 75 150 150 fil (cfm) 1040 1040 1040

_ weighting factor 0.363 0.593 0.567' 4-8 hr To (min) 0 75 30/150 15/60/150

_ fo (cfm) 0 1040 10/1040 500/10/1040 T1I - To (min) 120 240 240 240

_f] (cfm) 1040 1040 1040 1040

_weighting factor 0.514 0.487 0.309 0.296 Total weighting factor 0.514 0.849 1.083 1.296 Effective intake volume (cf) 9816 4218 150 937.5 Total weighted intake (c) 10005 Note 1: For example, the weighting factor for the time interval 1.5-4 hrs due to activity intake during the time interval 0-0.5 hrs is calculated as follows:

WF=1040 cfm/1040 cfm*EXP[-(15 min*500 cfm+60 min*10 cfm)/173000 ft3]*[1-EXP(-1040 cfm*150 min/173000 ft3)] =0.567 Page 22 of 42 Thyroid dose weighting factor, co-incident iodine spike, with CREBAPS operation

Attachment A (continued)

L-03-007 Thyroid dose weighting factor, co-incident iodine spike, with CREVS operation (The weighting factor is normalized to the value corresponding to fl = 1040 cfm, To= 0, & T1= co)

Intake Time Interval 4-8 hr 1.5-4 hr 0.5-1.5 hr 0 - 0.5 hr (Tave=6 hr)

(Tave=2.75 hr)

(Tave=I hr)

(Tave=0.25 hr) 0-0.5 hr To (mm) 0 fo (cfm) 0 TI -To (min) 15 fi (cfm) 500 I weighting factor 0.088 0.5-1.5 hr To (min) 0 15 fo (cfm) 0 500 TI -To (min) 30 60 fi (cfm) 1040 1040 weighting factor 0.165 0.290 1.5-4 hr To (min) 0 30 15/60 fo (cfm) 0 1040 500/1040 TI - To (min) 75 150 150 fl (cfm) 1040 1040 1040 weighting factor 0.363 0 496 0.397 4-8 hr To (mm) 0 75 30/150 15/60/150 fo (cfm) 0 1040 1040/1040 500/1040/1040 T 1 -To (min) 120 240 240 240 f] (cfm) 1040 1040 1040 1040 weighting factor 0.514 0487 0.259 0.207 Total weighting factor 0.514 0.849 0.920 0.982 Effective intake volume (cf) 9816 4218 613.5 937.5 Total weighted intake (cf) 10113 The above assessment demonstrates that the thyroid dose scaling factor for the co incident iodine spike case, with proper consideration of dose contribution from the time dependent intake activity, is 10,113 /10,005 = 1.011.

This value is bounded by the scaling factor conservatively estimated in Table 2.0.11-1 (1.033).

Similarly, it can also be shown that the thyroid dose scaling factor estimated in Table 2.0.11-2 for the pre-incident iodine spike case is also a bounding value.

Page 23 of 42

Attachment A (continued)

L-03-007 Item 2.0.12 Section 5.3.7.3.2 addresses Emergency

Response

Facility (ERF) habitability. Unfiltered inleakage during normal operation is stated to be 2090 cfm, while emergency mode inleakage is stated as 910 cfm, which includes 10 cfm for ingress and egress.

"* Please explain the basis of these inleakage values. Are these the result of testing?

" Given the multiple points of ingress and egress to the ERF, and the large number of people expected to populate the ERF, please explain why only 10 cfm is considered appropriate for ingress and egress.

Response to Item 2.0.12 Unfiltered inleakage at the Emergency Response Facility (ERF) during normal operation of the ventilation system is assumed to be 2090 cfm, which was derived by assuming 50% of the maximum design filtered intake flow (3800 cfm + 10%). Although the ERF is not pressurized, 50% is thought to be conservative. Filtration of the intake flow is by HEPA filters only, since the charcoal filters were removed from the ERF ventilation intakes in 1985. Normal operation is assumed to continue for 30 minutes, until ERF personnel begin to arrive and shift the ventilation system into the emergency recirculation mode. Thus, the analysis is based upon a total unfiltered inflow of 5890 cfm (3800 cfm design flow of the fan plus 2090 cfm inleakage), during the time period T=0 to T=30 minutes after a LOCA.

The emergency recirculation flow (also 3800 +/- 10%) path is equipped with both HEPA and charcoal filters. Unfiltered inleakage in the recirculation mode was estimated at 910 cfm, including an allowance of 10 cfm for ingress and egress. The remaining 900 cfm unfiltered inleakage consists primarily of a nominal 800 cfm allowance for the contribution created by operation of the switchgear room exhaust fan. The switchgear room is technically outside the ERF ventilation envelope, but the exhaust fan draws air from the switchgear room that is made up by air from within the envelope in order that it remains clean.

It is assumed that all of this makeup air is drawn from unfiltered inleakage sources. The air in the ERF is sampled by an air particulate monitor located just outside the Emergency Operations Facility (EOF).

Page 24 of 42

Attachment A (continued)

L-03-007 The balance of the assumed inleakage is conservatively based on infiltration and exfiltration component leakage flow measurements performed in 1996 (75 cfm), together with an additional 20 cfm allocated to potential degradation of the intake isolation damper between the filter and the fan, based on the maintenance history of similar dampers. A further allowance of 5 cfm is provided for the north door seals, since this door opens directly from the Technical Support Center to the outside environment. Other ERF design parameters remain consistent with the previous analysis of record.

The allowance for ingress and egress was based on the Standard Review Plan (SRP) guidance for control rooms, considering that after manning the ERF, the normal entrances are locked down by procedure, and all ingress and egress is performed via the garage on the South side of the building, which is equipped with a frisker and a decontamination station.

Because entrance through the garage involves passage through two doors, it behaves effectively as a double door vestibule. Once manned, ERF personnel are trained to remain at their assigned stations within the ERF until Health Physics (HP) collects air samples, and the direction and speed of the release plume (if any) has been ascertained.

After manning is completed, further ingress and egress is controlled and monitored by HP.

Item 2.0.13 At the top of page 5-53, a statement is made that it is conservative to model the ERF as a point receptor. Please explain the conclusion that this is conservative.

Treating the ERF in this manner removes the source of exposure as soon as the plume blows by. However, given the 30-minute delay in placing the ERF in emergency mode and the high the amount of inleakage, the internal atmosphere of the ERF could be contaminated and be the source for extended exposure, even after the plume has cleared.

Response to Item 2.0.13 In section 5.3.7.3.2 of the Licensing Report, habitability of the ERF is demonstrated by calculating the doses due to inhalation and submersion, and due to external shine resulting from the containment structure (including skyshine), the ERF normal operation intake filter, and the ERF emergency ventilation recirculation filters. The calculated 30 day dose to an operator in the ERF is 3 rem total effective dose equivalent (TEDE), i.e.,

2.5 rem TEDE due to inhalation and submersion and 0.5 rem deep dose equivalent (DDE) due to external shine, and is within the regulatory limit of 5 rem TEDE. The inhalation and submersion doses were calculated by assuming the operator is outside the ERF building without taking credit for either the ERF ventilation systems or the ERF structure.

Page 25 of 42

Attachment A (continued)

L-03-007 The ERF ventilation system parameters are presented in Table 5.3.7-1 of the Licensing Report and parameters critical to this response are summarized below:

Minimum free volume 478,610 ft3

"* Filtered normal operation intake 3800 cfm (+/- 10%)

"* Normal operation filter eff. (HEPA) 99% (95% of the halogen and 100% of the alkali metals in containment leakage are in particulate form)

"* Normal operation unfiltered inleakage 2090 cfm *

"* ERF in emergency recirculation mode T = 30 minutes

"* Emergency recirculation rate 3800 cfm (+/- 10%)

"* Emergency recir filter efficiency 98% (particulate) 90% (elemental /organic iodine)

"* Emergency mode intake rate 0 cfm

"* Emergency mode unfiltered inleakage 910 cfm

• 2090 cfm is the assumed normal operation unfiltered inleakage value used in the analysis. The sensitivity of the dose estimate relative to this value is discussed later in this response.

The discussion provided below demonstrates that the inhalation and submersion doses following a LOCA to an operator outside the BVPS ERF, is greater than the doses inside the ERF.

Inhalation Dose Generic Comparison between External Point Receptor Model vs Building Enclosure Model The following generic case is utilized as part of this discussion:

A puff release of unit source (1 Ci of any radioisotope with a decay constant X)

A downwind location with an atmospheric dispersion factor of XQ (s/mi3)

A building enclosure with a volume V (mi3), and an intake (and exhaust) rate of f (m3/s)

The integrated concentration outside the building during the plume passage is 1 (Ci)

• X/Q (s/m 3) = x/Q (Ci-s/m3 ).

(Note that the radioactive decay during the short period of plume passage is ignored in this external point receptor model).

Page 26 of 42

Attachment A (continued)

L-03-007 The total intake of activity into the enclosure is 1 (Ci)

• x/Q (s/m 3)

• f (m3/s) = (X/Q) f (Ci).

The concentration in the enclosure at time t seconds after the release is (X IQ)f e-(~f +/)

e Ci/m 3 The integrated concentration in the building enclosure is f

(X /Q)f e_(A+fl, idt Ci-sec/m 3 V

If the intake and exhaust flow remains constant, the integrated concentration becomes (X/Q)f 1

Ci-sec/m 3 V

(A+f/V)

It is therefore concluded that, under the condition of constant intake and exhaust flow, the integrated concentration outside the enclosure (i.e.; X/Q (Ci-sec/m 3 ) in this evaluation) is always greater than that inside the enclosure. The difference factor, 1 + XV/f, is due to radioactive decay in the enclosure. In the case of long half-life isotopes or/and high exhaust rates, the radioactive decay is insignificant and the integrated concentration inside the enclosure will approach the value outside. If the exhaust rate changes, the integration factor, 1/(X+ f/V), will change accordingly. In the usual case where the dose is dominated by the longer half-life isotopes, the integrated concentration of the dominant isotopes varies approximately in reverse proportion to the exhaust rate.

Since the continuous release can be treated as a series of puff releases, the above conclusion that the outside integrated concentration (point receptor model) is greater than the inside integrated concentration (building enclosure model) by a factor of 1 + XV/f holds true as long as the exhaust rate remains unchanged.

Since the inhalation dose is in direct proportion to the integrated concentration, the outside inhalation dose is greater than the inside value by the same factor (assuming the same breathing rate and occupancy factor).

Application to BVPS ERF Dose Analysis For the BVPS ERF, the exhaust rate changes at T = 30 minutes when the ventilation mode is switched from the normal operation mode to the emergency mode. Before T =

30 minutes, the exhaust rate is the sum of the intake of 3800 cfm and the inleakage of 2090 cfm for a total of 5890 cfm. After T = 30 minutes, the ERF is exhausted at the inleakage rate of 910 cfm. This significant reduction of depletion rate results in bottling up the contaminated air in the ERF and could potentially result in a greater dose to an Page 27 of 42

Attachment A (continued)

L-03-007 operator inside the ERF as compared to a person outside. However, as demonstrated below, the outside ERF model is still more conservative because of the filtration provided by the BVPS ERF intake and recirculation filters.

To simplify the discussion, the dose due to activity release prior to T=30 minutes and that after T=30 minutes is discussed separately.

For the activity released after T=30 minutes, the outside ERF model is always more conservative than the inside ERF model since there is no exhaust rate change after T=30 minutes. (See generic comparison above).

The discussion provided below focuses on the doses due to radioactivity released prior to T = 30 minutes.

For the activity release prior to T=30 minutes, the dose contribution to an operator based on the "outside ERF model" stops at T=30 minutes when the release terminates.

However, the dose contribution to an operator based on the "inside ERF model" will continue as long as the residue activity remains in the building.

The operator dose based on the "inside ERF model" depends on the intake of radioactivity into the ERF.

The effective intake rate of halogen into the ERF, taking into consideration the ERF intake ERF filter = 2090 + 3800 (0.95

• 0.01 + 0.05

• 1) = 2316 cfm, where 2090 cfm is the unfiltered inleakage rate, 3800 cfm is the filtered intake rate, 0.95 is the fraction of halogen in the particulate form, 0.01 is the reduction factor associated with a HEPA filter efficiency of 99%, and 0.05 is the fraction of halogen in elemental or organic form.

Note that the effective intake rate of alkali metals will be less because 100% of alkali is in particulate form.

The inhalation dose reduction factor for the operator based on the "inside ERF model" taking credit for the intake HEPA filter vs the point receptor "outside ERF model" is =

2316 cfm / (2090+3800) cfm = 0.393.

The operator dose associated with the "inside ERF model" also depends on the depletion rate of activity in the ERF.

The depletion rate of activity in the ERF equivalent to the "outside ERF model" is the exhaust rate during the intake period prior to ERF isolation, i.e., T=0 to T=30 minutes is

= 2090 + 3800 = 5890 cfm.

Page 28 of 42

Attachment A (continued)

L-03-007 The depletion rate of halogen in the ERF after 30 minutes with the "inside ERF model",

taking into consideration the ERF recirculation HEPA and charcoal filter:

= 910 + 3800 (0.95

• 0.98 + 0.05

• 0.9) = 4619 cfm, where 910 cfm is the inleakage rate, 3800 cfm is the filtered recir rate, 0.95 is the fraction of halogen in the particulate form, 0.98 is the HEPA filter efficiency, 0.05 is the fraction of halogen in elemental or organic form, and 0.9 is the charcoal filter efficiency.

Note that the depletion rate of alkali metals will be greater because 100% of alkali is in particulate form.

The ratio of the minimum depletion rate with recirculation filtration after T=30 minutes (inside ERF model) to the depletion rate assuming a constant intake and exhaust rate (outside ERF model) = 4619 cfm / 5890 cfm = 0.7842 Consequently, the ratio of integrated concentration (from T = 30 minutes to T=30 days) for the case of 910 cfm inleakage and 3800 cfm filtered recirculation (inside ERF model),

to the integrated concentration for the case of constant 5890 cfm total exhaust, for the long half-life isotopes (outside ERF model) would be the inverse of the ratio of the deletion rate, i.e., 1/0.7842 = 1.28. Note that the concentration ratio will be smaller for shorter half-life isotopes.

Combining the reduction factor of 0.393 due to intake filtration, and the factor increase of 1.28 due to the reduced exhaust rate but crediting the recirculation filtration results in a net reduction factor of 0.5 for the integrated concentration in the ERF from the activity released prior to T=30 minutes for the "inside ERF model" vs the "outside ERF model."

Consequently, with regards to the activity release prior to T=30 minutes, due to the operation of the ERF ventilation filters, the "outside ERF model" will result in a higher dose estimate than the "inside ERF model".

Submersion Doses For the submersion dose which is dominated by noble gases, the external point receptor model utilizes the semi-infinite cloud model. Based on Regulatory Guide 1.183, the finite cloud dose reduction factor for the ERF can be calculated based on 1173/VN338.

The ERF volume (V) is 478,610 ft3 and the reduction factor is 14, which is greater than the noble gas concentration increase factor due to reduced exhaust (5890 cfm / 910 cfm =

6.5) for the "inside ERF model."

Page 29 of 42

Attachment A (continued)

L-03-007 Conclusion In summary, the above discussion shows that for the activity released before T=30 minutes, the external point receptor model is conservative because of the filtration credits of the intake/recirculation filters and the use of semi-infinite dose model. In addition, and as noted in the generic discussion provided earlier, when there is no change in the exhaust rate, as is the case after T=30 minutes, the external point receptor model is always more conservative than the inside enclosure model.

Therefore, it is concluded that the point receptor model (outside ERF model) used to calculate the inhalation and submersion dose to an operator in the ERF is conservative. It is noted that the above discussion is focused on the containment leakage pathway. It is clear that the point receptor model for the Engineered Safety Features (ESF)/Refueling Water Storage Tank (RWST) leakage pathways are also conservative specially because the major dose contribution is a result of the activity release after T=30 minutes and because the elemental/organic iodine in the ESF/RWST leakage is rapidly cleaned-up by the recirculation filters.

Sensitivity of ERF Dose to Variations in Unfiltered Inleakage The above analysis is based on the normal operation unfiltered inleakage rate of 2090 cfm prior to ERF isolation, which is an assumed value based on one half of the intake rate plus 10%. (See Response to RAI Item 2.0.12 for details).

In a more restrictive case assuming that the inleakage equals to the intake (3800 cfm), the reduction factor for the activity released prior to T=30 minutes due to intake filtration is 0.530, and the increase factor due to reduced exhaust is 1.65, resulting in a net reduction factor of 0.87 for the "inside ERF model" relative to the "outside ERF model."

It is also noted that any increase of the emergency mode unfiltered inleakge (910 cfm) will actually improve the calculated concentration ratio, thus making the "outside ERF model" even more conservative for determining the dose contribution due to activity releases prior to T=30 minutes.

In addition, with regards to the submersion dose for this more restrictive case, the finite cloud dose reduction factor for the ERF (which is 14), will remain greater than the noble gas concentration increase factor due to reduced exhausting (7600 cfm / 910 cfm = 8.4) for the "inside ERF model".

Page 30 of 42

Attachment A (continued)

L-03-007 Item 2.0.14 In Table 5.3.6-2, the duration of the containment vacuum release is given as 5 seconds. What is the basis of this assumption? Why is this release path not considered for the containment leakage path in the CREA analysis?

Response to Item 2.0.14 The containment vacuum lines penetrations are isolated by solenoid and air-actuated isolation valves, actuated by a containment isolation phase A (CIA) signal from the solid state protection system. Although the maximum allowable stroke times given in the Licensing Requirements Manual (LRM) are 60 seconds for these valves, they are tested to acceptance criteria in the Inservice Testing (IST) Program of 5 seconds. Examination of the performance of these valves in recent surveillance testing confirmed that they are consistently tested successfully to within 5 seconds.

In addition, a change is being processed to the LRM under 10CFR50.59 to reduce the LRM acceptance criterion to 5 seconds, and the LOCA analyses were performed to this criterion.

The analyses computed the release from this path without crediting the downstream piping through the vacuum pumps, since the system is not safety grade.

The CREA analysis considers two independent release paths to the environment; first via containment leakage at the Technical Specification allowable value; and second, through the steam generators, which are assumed to have primary-to-secondary leakage at the maximum allowable Technical Specification limit of 150 gpd each. Each pathway is analyzed conservatively, as if the other did not exist.

Only the Reactor Coolant System (RCS) coolant activity is assumed to be present in the containment atmosphere prior to isolation of the containment vacuum release pathway at T= 5 secs. This is consistent with NRC guidance relative to the recommended design for containment isolation systems as provided in documents such as NUREG 0800, SRP 6.2.4, and BTP CSB-6-4 which indicate that the maximum closure time for valves in lines open to containment atmosphere should not exceed 5 seconds to assure that the valves will be closed before the onset of fuel failures. Note that the above guidance referred to radiological analyses and TID 14844 LOCA dose models, which address instantaneous release scenarios, and is therefore considered applicable to the CREA which continues to be an instantaneous release model in RG 1.183 evaluations.

Based on the LOCA assessment, it is concluded that the incremental dose contribution from the containment vacuum release path due to release of RCS at Technical Specification concentrations during the five seconds it takes to close this pathway, is negligible in comparison with the failed!melted fuel released due to a LOCA or a CREA via containment leakage. Consequently, the dose contribution due to the containment vacuum release pathway prior to containment isolation is assumed to be negligible for the containment leakage scenario in the CREA analysis.

Page 31 of 42

Attachment A (continued)

L-03-007 Item 2.0.15 In its submittal, FENOC has proposed the use of a proprietary computer code, SWNAUA, to determine containment spray removal coefficients. As noted in the submittal, SWNAUA is an extension of the NAUA code, that incorporates an aerosol removal by spray model not in the original code.

Although the NRC staff has, in limited cases, accepted the value of a spray removal coefficient based on SWNAUA in a design-basis application, the staff has not approved the NAUA or SWNAUA code. The staff has not been asked to review any topical report supporting the use of SWNAUA that would allow the staff to find the code generally acceptable for design-basis applications.

The results of the BVPS spray removal assessment is shown in Figure 5.3.6.1 of the FENOC submittal. The NRC staff is concerned that the shape and magnitude of the removal curve may not be adequately conservative for a DBA analysis. Explain why FENOC believes the conservatism of the determined removal rates is appropriate for DBA analysis.

Response to Item 2.0.15 The proprietary Stone & Webster SWNAUA computer program is a derivative from the NAUAiMOD4 program (Bunz et.al 1982) modified by Stone & Webster to calculate removal due to sprays.

Although it is correct that the NRC has never reviewed the SWNAUA code through a topical report, the NRC staff has previously reviewed the SWNAUA spray model associated with the Design Certification review of Combustion Engineering's System 80+ design. The resulting Safety Evaluation Report (NUREG 1462) concludes that; "The staff performed a comparative analysis of ABB-CE's spray model with its own spray model. The staff used the lower bound spray removal coefficient values in its analysis and found that the ABB-CE's model produce spray coefficients which were conservative relative to the staff's values. As a result, the staff finds ABB-CE's spray model proposed for the System 80+ containment design to be acceptable."

The NRC staff has previously reviewed the SWNAUA spray model in the recent Alternative Source Term application submitted by Fort Calhoun Station. In its Safety Evaluation Report the staff stated, "In its review of the proposed spray removal rates, the staff reviewed the brief description of the model provided by OPPD, reviewed the analysis inputs and assumptions, evaluated the reasonableness of the estimated removal rates, and reviewed the use of the estimated removal rates in the radiological analyses".

"...the staff finds that OPPD's modeling of containment spray removal is acceptable,..."

Model correlations implemented into SWNAUA tend to underestimate the spray removal coefficient.

The aerosol removal rates predicted by SWNAUA are conservative and appropriate for Design Basis Accident (DBA) analysis.

They are based upon plant Page 32 of 42

Attachment A (continued)

L-03-007 specific (BVPS Units I & 2) bounding parameters and scenario specific assumptions as provided by the NRC in NUREG-1465.

Steam condensation rates used as input to the SWNAUA calculations derive from the Stone & Webster LOCTIC containment response code. The LOCTIC code has been employed to calculate conservative design basis accident containment pressure and temperature responses on several applications and has been accepted by the NRC.

LOCTIC program control options for BVPS are selected to minimize aerosol removal, which is effected by higher containment pressure and temperature and a lower rate of steam condensation. For example, the pressure flash option of LOCTIC was used to minimize steam condensation rates. Steam condensation rates that form the input to the diffusiophoresis calculation of SWNAUA are taken from the LOCTIC prediction of steam removal from the containment atmosphere less the steam condensation rate on the heat sinks.

The adequacy of the shape and magnitude of the removal curve are justified in the response to Item 2.0.20.

Item 2.0.16 The fourth paragraph on Page 5-27, indicates that credit is taken for aerosol removal by diffusiophoresis and spray.

a.

Is the diffusiophoresis based on steam condensation on heat sinks alone, or also on spray droplets?

b.

If condensation on spray droplets is included, please provide a description of the condensation model and the spray droplets area used.

c.

For condensation on the heat sinks: is the area used a nominal (FSAR) area, or a minimum one?

Response to Item 2.0.16 (a)

Aerosol removal by diffusiophoresis is based on steam condensation on both heat sink surfaces and on spray droplets.

(b)

The spray droplets areas (i.e., drop size distribution) are not directly used to calculate the condensing rates in LOCTIC, but separately applied in the calculation of the spray thermal effectiveness which is an input parameter to LOCTIC.

Page 33 of 42

Attachment A (continued)

L-03-007 The steam condensation rates are calculated in LOCTIC as follows:

Except when the spray temperature is greater than the containment dew point temperature, the sprays are modeled as removing energy from the containment atmosphere without mass transfer. The spray thermal effectiveness is an input parameter that is a measure of how close the spray comes to thermal equilibrium with the containment atmosphere during its fall through the containment atmosphere.

At the end of each time step, the containment atmosphere inventories of mass and energy are updated to reflect heat and mass transfers due to sprays, sinks, and blowdown during that time step. If these inventories are seen to correspond to a saturated state, all water mass in excess of what can be vaporized (i.e. excess saturated liquid condensing from the atmosphere: dm,/dt) is deposited as liquid on the floor. Then, the aerosol removal rate due to diffusiophoresis is calculated in SWNAUA as:

dmd/dt

=

dm,/dt X Cm X R/ps where:

dmv/dt

=

the rate of change of aerosol mass due to diffusiophoresis dm,/dt

=

the rate of steam condensing Cm

=

the mass concentration of aerosol in sprayed volume Ps

=

the steam density in sprayed volume R

=

the ratio of aerosol deposition velocity to the steam deposition velocity (c)

For condensation on the heat sinks a minimum area was used.

Item 2.0.17 In the table on Page 5-3 1, the spray flow rates are not credited prior to 722 seconds, about 12 minutes. The blowdown of the reactor coolant system (RCS) occurs largely before this time. At BVPS, CNMT quench spray start much earlier on 2/4 CNMT hi-hi pressure signals. Did the LOCTIC runs that established the steam condensation rates assume the same time delay?

Was a sensitivity analysis performed?

Response to Item 2.0.17 Consistent with the timing laid out in NUREG-1465, the gap activity release period is assumed to begin 30 seconds after the hot-leg double ended rupture (HLDER) and to last for 30 minutes. The early in-vessel release period is assumed to follow with a duration of 1.3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br />. The Emergency Core Cooling System (ECCS) is then assumed to start (at 6,510 seconds) and to quench the damaged core.

Page 34 of 42

Attachment A (continued)

L-03-007 The LOCTIC runs which established the steam condensation rates did consider quench spray initiation at 89 seconds after DBA initiation and recirculation spray at 722 seconds after DBA initiation.

No credit is taken for spray removal of aerosols until after 722 seconds. Diffusiophoretic aerosol removal is modeled between 30 and 722 seconds from the condensation rates calculated by the LOCTIC code.

The table on Page 5-31 of the Licensing Report is applicable to particulate removal by sprays.

No sensitivity analysis was performed since the LOCTIC runs, which predicted the condensation rates, are based upon conservative spray initiation times.

Item 2.0.18 In the table on Page 5-31, the spray droplet radius is identified as 350 micro in the early part of the scenario. Justify the value of this parameter.

Response to Item 2.0.18 Beaver Valley Power Station Unit 1 has two types of containment spray nozzles; type 1/22 B60 and type 1713A. The 1/21 B60 type cover a flow fraction of 79% while the 1713A cover the remaining 21%.

Beaver Valley Power Station Unit 2 has only the 1713A model spray nozzles.

The value of 350 microns is the geometric mass mean droplet diameter for BVPS Unit 1 conservatively taken from manufacturer's spray droplet size measurements and weighted for flow fraction.

The value of 518.5 microns is the geometric mass mean droplet diameter for BVPS Unit 2 taken from manufacturer's spray droplet size measurements.

Judging from the BVPS Unit 2 quench spray flow and duration, average bounding mass mean radius of spray droplets of BVPS Units I and 2 are calculated to be 350 micron from 722 seconds to 18,000 seconds and 518.5 micron from 18,000 seconds to 345,600 seconds.

Justification for using the above mass mean radii of spray droplets is demonstrated in Figures 2.0.18-1 and 2.0.18-2. As shown in Figure 2.0.18-2, total combined airborne aerosol masses in the sprayed and unsprayed containment regions for the BVPS Units 1 and 2 bounding case is continuously higher (in other words, higher aerosol release to the adjacent environment from the containment atmosphere) than those for the BVPS Unit 2 specific limiting case based on 518.5 microns (i.e., MINESF case) during the time period up to 18,000 seconds. These sensitivity results are due to the following reasons:

Page 35 of 42

Attachment A (continued)

L-03-007

1)

BVPS Unit 2 specific cases have higher spray coverage fraction (i.e., 0.8) due to the quench spray which is not credited for the bounding case; Note that the major airborne aerosol masses are contributed from the unsprayed

region,

2)

The quench spray termination times for BVPS Unit 2 specific cases (i.e.,

17,185 seconds for MINESF case and 12,889 seconds for MAXESF case) are far longer than the end time of aerosol source release from the core into the containment (i.e., 6510 seconds); Note that as shown in Figure 2.0.18-1, most of the airborne aerosol masses are depleted in the sprayed region by 700 seconds (i.e., 7,200 seconds after accident) after source release stops at 6,510 seconds,

3)

BVPS Unit 2 specific cases have higher spray flow rates over bounding case; Note that higher spray flow means higher airborne aerosol removal.

Therefore, using the radius of spray droplet of 350 micron for the bounding case up to 18,000 seconds is reasonable and yet conservative.

Page 36 of 42

Attachment A (continued)

L-03-007 FIGURE 2.0.18-1: Airborne Aerosol Mass vs. Time (BV 1/2 Bounding Case vs. BV2 Specific Case)

U, 0

L.

0 I-60000 50000 40000 30000 20000 10000 0

0 1800 3600 5400 7200 9000 10800 12600 14400 16200 18000 Time (Sec)

Page 37 of 42

Attachment A (continued)

L-03-007 FIGURE 2.0.18-2: Airborne Aerosol Mass vs. Time (BV 1/2 Bounding Case vs. BV2 MINESF Case) 0 1800 3600 5400 7200 9000 Time (Sec) 10800 12600 14400 16200 18000 Page 38 of 42 U)

LO 0 0 0

0 I

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Attachment A (continued)

L-03-007 Item 2.0.19 The table on Page 5-32 provides values for parameters that have a significant impact on the value of the spray removal rate.

a.

Did you perform a sensitivity study on maximum aerosol radius and maximum number of size bins? If yes, please provide the results. If not, is it possible to run a case with smaller maximum radius (e.g.,

50 microns), and smaller maximum number of size bins (e.g., 30)?

b.

Please justify the conservatism of the aerosol densities of 3.7 and 4.6 gm/cc.

Do these values reflect the effective densities (i.e.,

accounting for porosity) or that of pure materials?

c.

Provide the basis of the values for mean geometrical radii and standard deviation and justify their conservatism.

Response to Item 2.0.19

a.

A sensitivity run was conducted using a maximum radius of 50 microns and a reduced number of bin sizes of 30. The resulting aerosol removal rates within the sprayed volume are compared with the results of the 100 micron and 100 bin case in Figure 2.0.19-1. As shown in Figure 2.0.19-1, the total aerosol removal rates (due to both sprays and diffusiophoresis) are similar between the two cases. A greater number of bin sizes, although requiring greater computational time, provides greater resolution.

The 100 micron max aerosol diameter is recommended as typical for NAUA/MOD4.

b.

In accordance with NUREG 1465, during the gap release phase, the release will be mostly CsI and CsOH, both of which are highly soluble.

Since CsOH is the dominant component of the two in terms of mass released, and since it has a lower density, the material density of CsOH (3.7 gm/cc) is used to characterize the gap release phase.

During the in-vessel release phase, in addition to fission product aerosols, large quantities of nonradioactive or relatively low activity aerosols will also be released into containment.

These aerosols arise from core structural and control rod materials.

The SASCHA'experiment found that the aerosols were composed mainly of the elements Ag, In, Cd, Cs, I, Te, and 0. The chemical composition of the aerosol is only important as it relates to aerosol density.

The chemical composition during the in-vessel release phase is 20% of CsOH (soluble), 20% of

'H. Albrecht, H. Wild, Review of the Main Results of the SASCHA Program on Fission Product Release under Core Melting Conditions, ANS Meeting on Fission Product Behaviour and Source Term Research, Snowbird, Utah, 15-19 July, 1984.

Page 39 of 42

Attachment A (continued)

L-03-007 In (insoluble), and 60% of Ag (insoluble), with an effective aerosol density of 4.6 gm/cc.

c.

The RAFT [A Computer Model For Formation and Transport of Fission Product Aerosols in LWR Primary Systems, ANS Topical Meeting, July 1984] predictions are used to estimate the particle size distribution.

The results of the STEP-1 experiment which is a scaled representation of a large break LOCA (hot leg DER) without ECCS indicate that the RAFT predictions are conservative; i.e., the particle sizes in the experiment are larger than those predicted by RAFT.

The particle size distribution for the gap release could be approximated with the 500 second distribution from the RAFT predictions.

This distribution was graphically calculated to have a geometric mean radius of 0.075 microns and a standard deviation of 1.56.

The particle size distribution for the early in-vessel fuel release could be approximated with the 800 second distribution from the RAFT predictions. This distribution was graphically calculated to have a geometric mean radius of 0.4 microns and a standard deviation of 1.46.

The standard deviation is calculated by either; c7=rg/r(P{16%})

or u = r (P{84%})/rg where (Y is the standard deviation, rg is the geometric mean, and r (P{16%}) and r (P{84%}) are the particle radii with a non-exceedance probability of 16% and 84% respectively.

Page 40 of 42

Attachment A (continued)

L-03-007 FIGURE 2.0. 19-1 Aerosol Removal Rates Within Sprayed Volume (NUREG-1465 HLDER MIN CASES) 60 50 30 0

E o 20 E0 10 10 0

0 1800 3600 5400 7200 9000 10800 12600 14400 16200 18000 Time (Sec)

Item 2.0.20 Provide an explanation of the relatively high removal rates (i.e., 40-60 per hour) between 1800 and 6600 seconds of the accident shown on Figure 5.3.6-1 on Page 5-85.

Response to Item 2.0.20 During the gap release phase (time between 30 and 1,800 seconds), aerosol removal by diffusiophoresis dominates over spray removal, since the aerosol concentration in the containment is relatively low due to low source rate (6.13 gm/sec) and since aerosol size is relatively small (mean geometrical radius of 0.075 micron). Therefore, total aerosol removal rates during the gap release phase are low (; 5 per hour).

Page 41 of 42 I

I I

Max Radius=100 microns, Bin Size=100 Max Radius=50 microns, Bin Size=30 I

Attachment A (continued)

L-03-007 As noted in the response to 2.0.17, the early in-vessel release period will follow the gap release phase (<1,800 seconds) with a duration of 1.3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br />. The ECCS is assumed to start (at 6,510 seconds) and to quench the damaged core.

The total aerosol removal rate therefore increases between 1,800 and 6,600 seconds due to; i)

High source rate (58.55 gm/sec) with relatively large size of aerosol (mean geometrical radius of 0.4 micron) is introduced into the containment during the in-vessel release phase.

ii)

High gravitational agglomeration results due to high aerosol concentration in the containment during the in-vessel release phase. The spray removal is more effective for larger sizes of aerosol.

iii)

Additional high aerosol removal rate by diffusiophoresis is anticipated after 6,510 seconds when the high steam condensation rates occur during the core quenching period.

6,600 seconds after accident initiation, aerosol removal rates decrease sharply, since the aerosol concentration in the containment drops rapidly.

Page 42 of 42

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Attachment D to L-03-007 Meteorological Data The attached Compact Disk (CD) contains the 1990-1994 BVPS on-site meteorological data input to ARCON96, in the ARCON96 input data format.

The data is contained in file arconbv.met.

Attachment E to L-03-007 Revised Containment Conversion Licensing Report Figures.

Attachment E (continued)

L-03-007 Discussion of Figure Revisions A corrected version of Figure 4.1-4 was submitted in response to Item 1.2.2 of the subject RAI by FENOC letter L-02-115 dated December 2, 2002, to correct an inconsistency on the ordinate scale. It has been determined that a similar inconsistency exists on Figure 4.1-5 of the Containment Conversion Licensing Report, which was submitted in support of License Amendment Requests (LAR) 300 (Unit 1) and 172 (Unit 2). Thus, revisions to these two figures is being provided.

The revised figures reflect the fact that the initial pressure used was the maximum initial pressure specified in Table 4.1-3 of the Containment Conversion Licensing Report. The version of Figure 4.1-4 transmitted by L-02-115 was intended to correct an ordinate scale inconsistency by revising the pressure plots for the upper compartment. However, this revision inadvertently also revised the temperature plots for the upper compartment and break compartment.

The temperature plots on Figure 4.1-4 that was transmitted by L-02-115 inadvertently presented the temperature profiles that result from the containment pressure parameters, which result in lower containment gas temperatures in those regions removed from the break node. Therefore, a revised version of Figure 4.1-4 is provided by this transmittal. This version corrects the ordinate scale inconsistency on the pressure plot and contains the temperature plots as originally provided in the Containment Conversion Licensing Report.

Figures 4.1-4 and 4.1-5 are composite figures that illustrate the limited sensitivity of the containment's pressure and temperature responses to the postulated loss of coolant accident break locations. Thus, per the parameter matrix provided in Table 4.1-3 of the Containment Conversion Licensing Report, unique sets of parameters are used to quantify the containment pressure response and the long term containment temperature response.

FENOC has conducted an investigation into the cause of the previously mentioned figure inconsistencies and determined that these figures are the only composite figures in the Licensing Report. The composite figures were produced by manually inputting data to create the curves. The inconsistencies were caused by human error during the transcription of the data when generating the composite figures. The investigation determined that the problem was isolated to only the composite figures and does not affect the analysis conducted to support the conversion to an atmospheric containment.

Page E-I of E-3

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