ML081200643
| ML081200643 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 04/29/2008 |
| From: | Gerald Bichof Dominion Nuclear Connecticut |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 08-0248 | |
| Download: ML081200643 (20) | |
Text
Dominion Nudear Connecticut, Inc.
')000 Dominion Boulevard, Glen Allen, Virginia 2.1060 lJVeh Address: www.dom.com April 29,2008 U. S. Nuclear Regulatory Commission Attention: Document Control Desk One White Flint North 11555 Rockville Pike Rockville, MD 20852-2378 Serial No.:
08-0248 NLOS/MAE: R2' Docket No.:
50-423 License No.: NPF-49 DOMINION NUCLEAR CONNECTICUT, INC.
MILLSTONE POWER STATION UNIT 3 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING STRETCH POWER UPRATE LICENSE AMENDMENT REQUEST REVISED RESPONSE TO QUESTIONS EEEB-07-0052, EEEB-07-0054 AND EEEB-07-0055 Dominion Nuclear Connecticut, Inc. (DNC) submitted a stretch power uprate license amendment request (LAR) for Millstone Power Station Unit 3 (MPS3) in letters dated July 13, 2007 (Serial Nos.
07-0450 and 07-0450A),
and supplemented the submittal by letters dated September 12, 2007 (Serial No.
07-0450B), December 13,2007 (Serial No. 07-0450C), March 5, 2008 (Serial No.
07-04500), March 27, 2008 (Serial No. 07-0450E) and April 24, 2008 (Serial No.
07-0450F). The NRC staff forwarded requests for additional information (RAls) in October 29, 2007, November 26, 2007, December 14, 2007 and December 20, 2007 letters.
DNC responded to the RAls in letters dated November 19, 2007 (Serial No. 07-0751), December 17, 2007 (Serial No. 07-0799), January 10, 2008 (Serial Nos. 07-0834, 07-0834A, 07-0834C, and 07-0834F), January 11, 2008 (Serial Nos. 07-0834B, 07-0834E, 07-0834G, and 07-0834H), January 14, 2008 (Serial No. 07-08340), January 18, 2008 (Serial Nos. 07-0846, 07-0846A, 07-0846B, 07-0846C, and 07-08460), January 31, 2008 (Serial No. 07-08341),
February 25,2008 (Serial Nos. 07-0799A and 07-0834J), March 10,2008 (Serial Nos. 07-0846E and 07-0846F), March 25, 2008 (Serial No. 07-0834K) and April 4, 2008 (Serial No. 07-0834L).
The NRC forwarded an additional RAI in an April 23, 2008 letter.
This RAI requested information on previously answered Questions EEEB-07-0052, EEEB-07-0054 and EEEB-07-0055.
DNC is providing revised responses to these questions in the attachment to this letter.
These revised responses supersede the original responses to these questions that were provided in our January 10, 2008 and March 25, 2008 letters (Serial Nos. 07-0834C and 07-0834K).
The information provided by this letter does not affect the conclusions of the significant hazards consideration discussion in the December 13, 2007 DNC letter (Serial No. 07-0450C).
Serial No. 08-0248 Docket No. 50-423 SPU RAI, Revised Responses Page 2 of 3 Should you have any questions in regard to this submittal, please contact Ms.
Margaret Earle at 804-273-2768.
Sincerely,
,Idd74-/D Gerald T. Bischof Vice President - Nuclear Engineering COMMONWEALTH OF VIRGINIA COUNTY OF HENRICO The foregoing document was acknowledged before me, in and for the County and Commonwealth aforesaid, today by Gerald T.
Bischof, who is Vice President
- Nuclear Engineering of Dominion Nuclear Connecticut, Inc.
He has affirmed before me that he is duly authorized to execute and file the foregoing document in behalf of that Company, and that the statements in the document are true to the best of his knowledge and belief.
Acknowledged before me this d!lJ!:day of~
' 2008.
My Commission Expires: A1au 31, dolO. ~
7J
--'<::t&l~1 G".,:.=~~'L.Lt:..:.-.2It~<.ftoC:::....--
Notary Public VICKI L. HULL NotCItY PublIc Commonwealth of YI9nIO lo101a CCMNnIIIIon 11,.,.
Commitments made in this letter: None Attachment cc:
U.S. Nuclear Regulatory Commission Region I Regional Administrator 475 Allendale Road King of Prussia, PA 19406-1415 Mr. J. G. Lamb Project Manager U.S. Nuclear Regulatory Commission One White Flint North 11555 Rockville Pike Mail Stop 0-8B1A Rockville, MD 20852-2738 Mr. J. D. Hughey Project Manager U.S. Nuclear Regulatory Commission One White Flint North 11555 Rockville Pike Mail Stop 0-8B3 Rockville, MD 20852-2738 NRC Senior Resident Inspector Millstone Power Station Director Bureau of Air Management Monitoring and Radiation Division Department of Environmental Protection 79 Elm Street Hartford, CT 06106-5127 Serial No. 08-0248 Docket No. 50-423 SPU RAI, Revised Responses Page 3 of 3
Serial No. 08-0248 ATTACHMENT LICENSE AMENDMENT REQUEST STRETCH POWER UPRATE LICENSE AMENDMENT REQUEST RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REVISED RESPONSE TO QUESTIONS EEEB-07-0052, EEEB-07-0054 AND EEEB-07-0055 MILLSTONE POWER STATION UNIT 3 DOMINION NUCLEAR CONNECTICUT, INC.
Serial No. 08-0248 Docket No. 50-423 Attachment, Page 1 of 16 Stretch Power Uprate License Amendment Request Response To Request For Additional Information Revised Response To Questions EEEB-07-0052, EEEB-07-0054 And EEEB-07-0055 By letter dated July 13, 2007, as supplemented by additional letters, Dominion Nuclear Connecticut, Inc. (DNC), licensee of Millstone Power Station, Unit NO.3 (MPS3),
submitted the application, "Dominion Nuclear Connecticut, Inc.,
Millstone Power Station Unit 3, License Amendment Request, Stretch Power Uprate," to the U.S. Nuclear Regulatory Commission (NRC). The proposed license amendment would allow an increase in the maximum authorized power level from 3,411 megawatts thermal (MWt) to 3,650 MWt, and make changes to the technical specifications, as necessary, to support operation at the stretch power level.
The U.S. Nuclear Regulatory Commission (NRC) staff has been reviewing the submittal and has determined that additional information is needed to complete its review.
ELECTRICAL ENGINEERING BRANCH NRC Question EEEB-07-0052 Follow-Up (EEEB-oS-o10S)
In the March 25, 2008, letter, the licensee states that the analysis for the Main Steam Valve Building (MSVB) following a main steam line break (MSLB) is performed for the duration of the component's mission time. Specify the mission time and function for each of the affected components in the MSVB. Describe the effects of the increased temperature and pressure on the affected components.
In addition, explain, in detail, the assumptions and methodology used to evaluate the components. Provide a comparison of the pre-stretch power uprate (SPU) and SPU environmental temperature and pressure profile. Also, provide the detailed environmental qualification (EQ) evaluations and calculations for the ASCO solenoid valves, NAMCo limit switches, Rosemount pressure transmitters, Limitorque motor-operated valves and solenoids associated with Sulzer main steam isolation valves (MSIVs) and ITT actuators.
NRC Question EEEB-07-0052 Follow-Up (EEEB-oS-o109)
Provide the worst-case breaks and their impact on the EQ components for the MSVB EQ analysis.
Serial No. 08-0248 Docket No. 50-423 Attachment, Page 2 of 16 NRC Question EEEB-07-0052 Follow-Up (EEEB-08-0110)
In the March 25, 2008, letter, the licensee states that the outside temperature (Le.
component casing temperature) of the equipment, instead of the internal temperature of the equipment, was conservatively compared with the component qualification temperature. Provide a basis for why the outside temperature is conservative for the affected EQ components.
NRC Question EEEB-07-0052 Follow-Up (EEEB-OS-0111)
During the March 31, 2008, teleconference, the licensee stated that due to the temperature increase in the MSVB, a design change (enclosing the Limitorque motors with insulation) will be required to maintain the qualification of the motors.
Describe the design change in detail and provide a detailed evaluation justifying how this new design, (enclosing the motors with insulation), does not impact the original qualification configuration of the Limitorque motors. In addition, provide a schedule for implementing the aforementioned design change.
NRC Question EEEB-07-0052 Follow-Up (EEEB-08-0112)
Do the motor-operated valves installed in the MSVB use magnesium rotors? If yes, then evaluate the impact of high temperatures on the motors due to the SPU to ensure that these motors do not experience the failure mechanism identified in Information Notice 2006-26 and industry operating experience.
NRC Question EEEB-07-0052 Follow-Up (EEEB-OS-0113)
In the March 25, 2008, letter, the licensee stated that the ITT actuators are not required to mitigate the consequences of an MSLB in the MSVB. Provide the function of the ITT actuators and the impact on other components or systems if the ITT actuators fail due to MSLB in the MSVB under SPU conditions.
ONC Revised Response Main Steam Valve Building Harsh Temperature Environment Stretch Power Uprate (SPU) has no impact upon Main Steam Valve Building (MSVB) environmental temperatures, except for a MSVB high energy line break (HELB).
Dominion Nuclear Connecticut, INC.
(DNC) has finished the electrical environmental qualification (EQ) assessment for credited electrical components located in the MSVB (described in license amendment request (LAR) Section 2.3.1.2.3.2). The potentially impacted components are: ASCO Solenoid valves, NAMCo limit switches, Rosemount pressure transmitters, Limitorque motor
Serial No. 08-0248 Docket No. 50-423 Attachment, Page 3 of 16 operated valves, Sulzer main steam line isolation valve (MSIV) solenoids, and ITT damper actuators. The ONe analysis demonstrates that existing qualification temperatures are in excess of the calculated peak post-SPU operating temperatures for these components, or it was verified that qualification or operability is not required to mitigate the MSVB HELB, including post-accident monitoring design functions.
Analysis Overview for the MSVB Harsh Temperature The limiting MSVB environments were determined by the analysis of 56 MSVB HELB cases. Eleven break sizes of 0.05, 0.10, 0.20, 0.30, 0.40, 0.50, 0.60, 0.70, 0.80,0.90 and 1.0 ft2 were analyzed. The case definitions are summarized as:
a.
Eleven break sizes were analyzed at 102% and 70% SPU nuclear steam supply system (NSSS) power levels to maximize the enthalpy of superheated steam releases (22 cases).
The assumptions made for the cases which maximize the enthalpy of superheated steam releases are intended to cause early uncovery of the tube bundle in the shell of the steam generator, resulting in maximum enthalpy of the steam released.
b.
Eleven break sizes were analyzed at 102% and 70% SPU NSSS power levels to maximize the duration of steam release and soak time (22 cases).
The assumptions made for the cases which maximize hot environmental soak time are intended to maximize the duration of the transient which is primarily accomplished by increasing the mass available for release from the break.
c.
Twelve cases were analyzed for the Tavg coastdown for the break sizes from 1.0 ft2 to 0.5 ft2. Each break size was analyzed for both maximum enthalpy and maximum soak time. This analysis includes an accounting for the end-of-cycle Tavg coastdown from 589.5°F to 571.5°F. This is of concern because the actual reactor coolant system (ReS) average temperature may be as much as 18°F cooler at the end of the fuel cycle, but the Tavg and 11T reference temperatures for the overpressure delta temperature (OPI1T) and over temperature delta temperature (OTI1T) setpoints remain at the high-Tavg value. Therefore, the cases which trip on OPI1T are reanalyzed with new values related to the Tavg coastdown: nominal Tavg, steam temperature, pressurizer water level, and SG mass while maintaining the reference 11T and Tavg used in the OTI1T and OPI1Tsetpoint equations.
In cases which did not result in an automatic main steam isolation (MSI) signal on OPI1T or low steam line pressure, manual initiation is modeled at 1800 seconds.
The mass and energy (M&E) releases into the MSVB were used to determine the
Serial No. 08-0248 Docket No. 50-423 Attachment, Page 4 of 16 MSVB environments for the cases described above.
In addition to the event scenarios, sensitivity studies were performed for the MSVB initial conditions of temperature, humidity and pressure. Using these results, a thermal lag analysis for the required components in the MSVB was performed to determine the peak component temperature at the time it is required to perform its design function.
Consistent with current design and licensing basis, the analysis is performed for the duration of the components' mission time, which is the time period from the initiation of the HELB until the point within the event that the component is required to perform its intended design function.
A comparison of the enveloping pre-and post-SPU environmental temperature profiles is provided in Figure 1. The current EQ pressure profile envelopes post-SPU pressure profiles for all cases analyzed. Therefore there is no change to the EQ pressure profile. The enveloping EQ pressure profile is shown in Figure 2.
Aseo Solenoid Valves:
The primary function of the ASCO solenoid valves in the MSVB is to de-energize such that their respective valves change to the required safe position under a HELB environment.
Once this function is complete, no further post accident functions are required.
Pre-SPU ASCO solenoid valve thermal lag analysis used a
bounding environment temperature profile (i.e., 1.0 ft2 break size, 102% NSSS power level, maximum enthalpy) and a maximum mission time of 1800 seconds.
This maximum mission time bounds the MSI times for all break sizes analyzed. The analysis also assumes that the valves are energized to account for coil heat generation.
The peak temperatures were determined for the solenoid coil, air gap and coil housing. The maximum post-SPU coil temperature is calculated by conservatively adding the temperature difference between the bounding pre-and post-SPU environment temperature profiles to the calculated peak pre-SPU coil temperature (See note on Figure 3).
The peak temperature for pre-SPU environment temperature profile for solenoid valve qualification is 494.2°F (See Figure 3, curve labeled Tamb). The peak temperature identified in the post-SPU environment temperature profile for solenoid qualification is 562.2°F (See Figure 1, curve labeled 1.0 sqft w/max enthalpy, 102%, initial MSVB temperature of 140°F). The pre-SPU solenoid coil temperature at the maximum mission time (1800 seconds) is 37rF (See Figure 3, curve labeled Tcoil). The post-SPU peak coil temperature as identified in the note on Figure 3 is 445°F and remains below the 450°F ASCO solenoid valve qualification temperature.
Serial No. 08-0248 Docket No. 50-423 Attachment, Page 5 of 16 NAMCo Limit Switches:
The function of the NAMCO limit switches is to complete the electrical circuit without a voltage drop when the contacts are closed and provide an open circuit resistance when contacts are opened following a HELB environment.
Unlike the thermal lag analysis for the ASCO solenoid valves, a bounding 1800-second mission time was not used for the NAMCo limit switches. Instead, the thermal lag analysis used the mission time for each specific break size that was determined in the HELB analysis (i.e., for each break size, the temperature is calculated for the period starting from break initiation until the MSI signal is received). The analysis for all break sizes used their corresponding worst case temperature profiles (Le., 102% SPU NSSS power level, maximum enthalpy).
Additionally, the 0.2 ff break size was analyzed using 70% SPU NSSS power level, and maximum enthalpy temperature profile, which resulted in the highest peak temperature. This is because MSI occurs much later for the 70% SPU NSSS power level case than the 102% SPU NSSS power level case. MSI for the 0.2 ft2 HELB at 70 % power case occurs at 1613 seconds.
The calculation assumes an initial casing temperature of 140°F. The calculated temperature of the phenolic inner casing at 1613 seconds is 338°F, which remains less than the 340°F qualification temperature for the most limiting NAMCO limit switch model.
Post-SPU ambient and component temperature profiles are provided in Figure 4.
Rosemount Pressure Transmitters:
The MSIVs isolate steam flow from the secondary side of the steam generators following a HELB.
The subject pressure transmitters provide signals to the MSIVs for steam line low-pressure isolation. For a MSVB HELB, these pressure transmitters must be capable of performing their intended function under the harsh environment.
The analysis for the Rosemount pressure transmitters uses a similar approach as that of the ASCO solenoid valves. The analysis was performed using a bounding temperature profile (i.e., 1.0 ft2 break size, 102% SPU NSSS power level, maximum enthalpy, 140°F initial temperature) and maximum mission time of 1800 seconds. Initial casing temperature of 140°F is assumed to maximize the pressure transmitter temperature. Post-SPU temperature profiles of the ambient and the pressure transmitter head are provided in Figure 5 for the 1.0 ft2 break size.
The calculated transmitter temperature at 1800 seconds is 276°F, which remains less than the 318°F qualification temperature.
Serial No. 08-0248 Docket No. 50-423 Attachment, Page 6 of 16 Limitorgue Motor Operators:
The only motor operated valves (MOVs) that credit Limitorque operator remote operation during a MSVB HELB are valves 3MSS*MOV18A1B/C/D.
These valves are used to isolate the steam generator atmospheric relief or relief bypass lines. 3MSS*MOV18A1B/C/D, are only required to perform their safety function to close for HELBs outside the break exclusion zone.
Therefore, only the steam line breaks within the MSVB that are outside of the break exclusion zone (BEZ) are considered.
A three inch diameter HELB is the worst case break for this analysis outside the BEZ.
The subject valve bodies contain steam during normal operation. Therefore, the analysis used initial motor casing surface temperatures that are higher than the initial ambient temperature.
The analysis was performed using temperature profiles from 0.05 ft2 and 0.1 ft2 break sizes (double ended guillotine break for a 3-inch diameter line).
Four cases for each break size were analyzed: 1) maximum enthalpy at 102% SPU NSSS power level, 2) maximum enthalpy at 70% SPU NSSS power level, 3) maximum soak time at 102% SPU NSSS power level, and 4) maximum soak time at 70% SPU NSSS power level. These cases were chosen to be bounding since they provide the temperature versus time profiles for maximum peak temperature and maximum time for exposure of the component to an elevated temperature prior to superheat and the maximum temperature at the end of the analysis time.
The analysis shows that.
3MSS*MOV18A1B/C/D motors require insulation to maintain the motor temperature below the qualification temperature during the MSVB HELB event.
The most limiting case with insulation was determined to be the maximum soak time at 70% power, 0.05 ft2 HELB, insulated case.
The peak MSVB environmental temperatures for all eight cases occur well within 3,600 seconds after break initiation. Therefore, the analysis was run for a period of 10,800 seconds (3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br />).
Although the environment temperature drops rapidly after one hour, the analysis assumed a 240.5°F temperature for the remaining portion of the transient. In addition to the external heat flux from the harsh environment to the motor casing, the analysis assumed conductive heat flux from the valve to the motor casing.
Therefore comparison of the higher casing temperature to the qualification temperature is conservative.
The insulated motor casing temperature at 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> is 265°F, which is less than the 315°F motor qualification temperature.
Post-SPU temperature profiles of the ambient and the motor casing are provided in Figure 6.
As part of SPU project implementation, a design change will be performed to insulate the 3MSS*MOV18A, B, C and D operator motors prior to exceeding 3411 MWt.
The subject motors are totally enclosed, non ventilated motors manufactured by Reliance and do not use magnesium rotors. They are qualified for 100% relative humidity. The design change proposes to install 1.5 inch thick
Serial No. 08-0248 Docket No. 50-423 Attachment, Page 7 of 16 flexible blanket type insulation covering only the motor.
Enclosing the motors with insulation is expected to increase the motor temperature during normal operation and thus, any impact that would reduce the motor service life will be evaluated.
The design change process will evaluate the proposed modification to ensure that the installed condition will maintain the original motor qualification (i.e., test condition is applicable to the installed condition). Casing temperatures will be monitored pre-and post-modification, and any impact on the qualified service life will be incorporated into the EQ program for these motors. As part of the design change, plant procedures will be updated such that the motors will be inspected more frequently and replaced when necessary.
In
- summary, with implementation of the insulation modification, 3MSS*MOV18A1B/C/D will perform their intended design function under SPU MSVB HELB environment.
Sulzer Solenoid Valves:
The MSIVs are required to close and to remain closed upon receiving a MSI signal.
The MSIVs are credited to isolate and mitigate the consequences of a HELB in the MSVB. The safety function of the Sulzer solenoid valves is to de-energize to close the MSIVs. The MSVB HELB environment resulting from the SPU conditions will result in the Sulzer solenoid valves exceeding their qualification temperature during this event. An evaluation has been performed to determine the consequences of any failure of the MSIV Sulzer solenoid valves when exposed to this MSVB HELB environment. The evaluation concluded that any electrical failure of the Sulzer solenoid valves under this event will not prevent the MSIVs from performing their design function because the identified failure modes for the solenoid valves all result in the MSIVs moving to their fail closed position thereby isolating the main steam lines.
Additionally, the evaluation concluded that any electrical failure of the solenoid valves will not result in a subsequent reopening of an MSIV during the event.
Therefore, the Sulzer solenoid valves are not required to be electrically qualified for the MSVB HELB temperature increase resulting from the SPU conditions.
ITT Actuators of Intake Assembly Dampers:
The ITT Actuators are part of the MSVB Ventilation System.
The ventilation system provides cooling for the components in the MSVB during normal operation.
Under accident conditions that generate a Safety Injection Signal (SIS), the MSVB Ventilation System is shut down (fans stopped, dampers closed) to establish the Supplementary Leak Collection and Release System (SLCRS) boundary for the MSVB. This allows SLCRS to draw a slight vacuum within the SLCRS boundary including the MSVB. SLCRS is designed for dose mitigation following an accident.
Serial No. 08-0248 Docket No. 50-423 Attachment, Page 8 of 16 SPU does not change the MSVB peak temperature resulting from any event, except for the MSVB HELB event. For accidents outside containment, such as a MSVB HELB, the dose mitigation capability of SLCRS is not credited in the radiological consequences calculation. The release point for accidents outside the containment is the turbine building.
Therefore, the radiological consequences of the HELB are not impacted by any failure of the MSVB Ventilation System to function as a SLCRS boundary. Therefore, the dose mitigation capability of SLCRS is not impacted by damper position.
The heat removal function of the MSVB Building Ventilation System is not credited in the environmental conditions calculation for the MSVB HELB.
The analysis assumes all dampers and vents are closed. Therefore, failure of the dampers in either open or close position following a HELB in the MSVB has no adverse impact on the resulting environmental conditions in the MSVB. If there is no adverse impact on the environmental conditions, then there is no adverse impact on other components or systems in the MSVB.
Conclusion The calculated peak post-SPU operating temperatures for ASCO Solenoid valves, NAMCo limit switches, Rosemount pressure transmitters and Limitorque motor operated valves are less than their existing qualification temperatures.
The Sulzer solenoid valves are not required to be electrically qualified for the MSVB HELB temperature increase resulting from the SPU conditions. The In actuators in the MSVB ventilation system are not required to be operable during a MSVB MSLB event.
Engineered Safety Features (ESF) Building and Aux Building - Radiological Changes The ESF EO Zones ES-01 and ES-07, and Aux Building EO Zones AB-19, AB-22, AB-24, and AB-31 in LAR Sections 2.3.1.2.3.3 and 2.3.1.2.3.4 were identified as requiring resolution for increased radiation levels due to SPU. The EO zones AB-24 and AB-31 evaluation concluded the total integrated dose (TID) remains below the threshold limits for all safety related components including those that contain complementary metal oxide semiconductors or Teflon materials.
Further, plant walkdowns and design document reviews were performed for safety related equipment in EO zones AB-19, AB-22, ES-01 and ES-07 to determine if additional equipment had to be added to the EO program as a result of the increase in radiation levels. The plant walkdowns and design document reviews provided information on component location with respect to the gamma source term (Le., factoring in distance from the source or location relative to penetrations) as well as the extent of beta shielding for the equipment (i.e., size and wall thickness of metal enclosures or if enclosures are open to the
Serial No. 08-0248 Docket No. 50-423 Attachment, Page 9 of 16 environment).
The source term used in calculating the TID is described in LAR Section 2.3.1.2.2, Page 2.3-4.
This analysis shows the component TID in EQ zones AB-19, AB-22, ES-01 and ES-07 remains below the dose threshold required for inclusion in the EEQ program (1.00E+04 Rads).
NRC Questions EEEB-07-o054 and EEB-07-o055 Follow-Up (EEEB-oS-o114)
In the January 10, 2008, letter, the licensee stated, in regards to license renewal, that the EQ program will re-evaluate EQ components to ensure that the current qualification remains valid for the period of extended operation.
The licensee also states that the SPU will not have any impact on the EQ program's ability to adequately manage the effects of aging on the intended functions of EQ components. Describe why the SPU has no impact on the EQ program in regards to license renewal, as stated in the July 13, 2007, submittal.
Please clarify whether EQ evaluations have been completed regarding the qualification of equipment for the period of extended operation.
ONC Revised Response:
The MPS3 EQ Program ensures that equipment remains within the bounds of its qualified life such that after maximum normal service conditions, the equipment retains sufficient capacity to perform its required safety function during design basis accident conditions.
The NRC Safety Evaluation Report (SER) for the MPS3 license renewal (NUREG-1838) concluded that the MPS3 EQ program can adequately manage the effects of aging on the intended function(s) of safety related EQ electrical components that meet the definition for a Time-Limiting Aging Analysis (TLAA) support program, as defined in 10CFR54.3, during the period of extended operation. EQ components with a qualified life of 40 years or more are considered TLAA for license renewal. Therefore, for the purposes of the MPS3 license renewal, the EQ Program will re-evaluate those EQ components with a qualified life of 40 years or more to ensure that the current qualification remains valid for the period of extended operation. Furthermore, the EQ program will ensure that any necessary refurbishment, requalification, or replacements of equipment will be performed prior to the end of their qualified life. Performance of preventive maintenance and surveillance activities and the ongoing monitoring of normal ambient conditions ensure that EQ components remain within the bounds of their original qualification and may be used to provide a basis for extending qualified life.
The normal and post accident SPU environments and the associated aging effects were reviewed for conformance to the acceptance criteria of the NRC SER for the license renewal of MPS3. The MPS3 EQ program utilizes bounding normal operating design temperatures, pressures and humidity levels for the purposes of establishing and maintaining qualified life for EQ components.
Serial No. 08-0248 Docket No. 50-423 Attachment, Page 10 of 16 These normal operating conditions, temperature, pressure and
- humidity, resulting from the MPS3 SPU, remain bounded by the existing normal operating design conditions utilized by the MPS3 EQ program (refer to ONe's July 13, 2007 letter (Serial No. 07-0450), Attachment 5, Licensing Report (LR) Section 2.3.1.2.3).
In containment, certain EQ components credit local area temperatures that are less than the design temperature.
These local area temperatures are monitored and provide justification for the lower temperatures that are used for equipment qualification.
Continued monitoring of these local area temperatures will identify any localized temperature changes resulting from the SPU, which will then be factored into the qualified life for these components (refer to LR Section 2.3.1.2.3.1).
Additionally in containment, certain EQ components have been identified with qualified lives of less than 40 years and have established replacement schedules.
These replacement schedules have not been impacted because the normal operating maximum temperature has not changed (refer to LR Section 2.3.1.2.3.1). Although the normal radiation levels will increase in areas except the MSVB and ESF Building due to the SPU, it has been determined from the qualification test profiles that the EQ components in those areas remain qualified for these increased radiation levels (refer to LR Section 2.3.1.2.3).
The SPU impacts on the EQ program accident environment conditions have all been evaluated. With the exception of the MSVB, the SPU environmental condition impacts were found to be bounded by the existing equipment qualification test profiles and the equipments' qualification is unaffected by the SPU transients (refer to LR Section 2.3.1.2.3).
The SPU increase in the accident temperature of the MSVB has been evaluated for the MSVB components and the results are provided in the revised response to RAI Question EEEB-07-0052 above.
In the ESF Building and Auxiliary Building, several zones were identified with increases in accident radiation levels that could potentially change them from mild to harsh environments.
The safety related equipment in these zones has been evaluated in detail and it has been determined that the total integrated dose remains below the threshold limits for all safety related components in those zones and do not need to be included in the EQ program (refer to the revised response to RAI Question EEEB-07-0052 above).
The SPU EQ evaluation concluded that the SPU will not impact the qualification of the MPS3 EQ components and that the MPS3 EQ program will continue to adequately manage the effects of aging on the EQ components during the period of extended operation. Therefore, for the purposes of the MPS3 license renewal, the EQ Program commitment to re-evaluate those EQ components with a qualified life of 40 years or more to ensure that the current qualification remains valid for the period of extended operation is unaffected.
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(::I Baa) 8Jnl8Jadwa.L Figure 3: Pre-SPU Temperature Profiles for ASCO Solenoid Valves Note: post-SPU peak coil temperature =pre-SPU peak coil temperature +
temperature difference between bounding pre-and post-SPU environmental profiles
= 37rF + (562.2°F - 494.2°F) = 37rF + 68°F = 445°F
100 +---~--------------I-------I--------!----------+--------j 600 -r------~-----_;__-----__.,..-----___r"-----___,.-----__.
1,800 1,500 i
i I
I 1,200 i
900 Time(sec)
l---I-------i-------I--:,.-L-----1 l-I 600 300 O+--.......--r----r-----,..-!-r---,--.......---.--+-----,..---,-.,---,--+--..-.....,.--,----,-+--,---,--..-.....,.--+---,-,.--.......---.--l o
(Namco Limit Switch Thermal Lag) 400 200
o o
i
[
I I
I i
MSVH Ambient Temperature (102% Power, Max Enthalpy wi 1.0 ftsq Break Case) r-;
I i
/
I I
I I
L/~I i
I i
Peak Temp = 275.6F at t = 1,800 I
I
~
I Transmitter Head Temperature i
I 1
L----~
i II II--~
1,800 1,500 1,200 900 Time (sec) 600 (Rosemount Pressure Transmitter Thermal Lag) 300 400 500 200 100 600 LL-e
- s-f! 300 Q)
Q.
E
~
Serial No. 08-0248 Docket No. 50-423 Attachment, Page 16 of 16 Limltorque 70% Power Maximum Soak Time (with Insulation)
Run 'InsuI3'. O.05sq.ft.
A I
\\
-Casing
-Insulation Surface
-Environment
\\
V
-\\
-V L.---' ~
I""'"
I 500 450 400 350 g
!i 300
~
250 200 150 100 o
900 1800 2700 3600 4500 5400 6300 Time(s) 7200 8100 9000 9900 10800 Figure 6: Post-SPU Limitorque Motor Temperature Profiles (with insulation)