ML20216E695

Refers to 960726 License Amend Request Submitted by NSP to Increase MNGP Operating License Max Power Limit & Revise Supporting MNGP Ts.Suppl to 980211 RAI Encl

ML20216E695
Person / Time
Site:	Monticello
Issue date:	03/06/1998
From:	Kim T NRC (Affiliation Not Assigned)
To:	Richard Anderson NORTHERN STATES POWER CO.
References
TAC-M96238, NUDOCS 9803180128
Download: ML20216E695 (5)

Text

{{#Wiki_filter:! March 6, 1998 Mr. Roger O.: Anderson, Director Licensing and Management lasues Northern States Power Company - 414 Nicolet Mall Minneapolis, Minneapolis 55401 l

SUBJECT:

MONTICELLO NUCLEAR GENERATING PLANT - REQUEST FOR ADDITIONAL INFORMATION ON LICENSE AMENDMENT REQUEST ~ ENTITLED " SUPPORTING THE MONTICELLO NUCLEAR GENERATING PLANT (MNGP) POWER RERATE PROGRAM" (TAC NO. M96238)

DearMr. Anderson:

By letter dated July 26,1996, Northern States Power Company (NSP) submitted a license amendment request to increase the MNGP operating license maximum power level to l 1775 megawatts thermal, and revise supporting MNGP Technical Specifications. This change i reflects an increase of 6.3 percent above the currently licensed power level of 1670 megawatts thermal.

- On April 14,1997, the staff issued its request for additional information (RAI) based on a preliminary review of the July 26,1996, submittal. NSP responded to the staff's RAI in a letter dated September 5,1997. Subsequently, by a letter dated December 4,1997, NSP submitted Revision 1 to the original submittal dated July 26,1996.

On February 11,1998, the staff issued its second set of RAI based on a review of the submittals dated September 5 and December 4,1997. The enclosed is a supplement to the staff's RAI dated February 11,1998. Please advise NRC of NSP's schedule for responding to the enclosed RAl. Sincerelyi ORIGINAL SIGNED BY Tae Kim, Senior Project Manager  ! Project Directorate ill-1 -{ Division of Reactor Projects -lil/lV , Office of Nuclear Reactor Regulation a a ed o e cc w/ encl: See next page. {$ Q ((h] @Q , DISTRIBUTION: L Docket File- OGC- PUBLIC ACRS I PD31 RF EAdensam (EGA1)- JMcCormick-Barger, Rlli -

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   ..-   Mr. Roger O. Anderson, Director     Monticello Nuclear Generating Plant Northem States Power Company ec:

J. E. Silberg, Esquire Kris Sanda, Commissioner q Shaw, Pittman, Potts and Trowbridge Department of Public Service ' 2300 N Street, N. W. 121 Seventh Place East Washington DC 20037 Suite 200 St. Paul, Minnesota 55101-2145 U.S. Nuclear Regulatory Commission Resident inspector's Office Adonis A. Nebiett l- 2807 W. County Road 75 Assistant Attomey General l Monticello, Minnesota 55362 Office of the Attomey General j 445 Minnesota Street l Plant Manager Suite 900

Monticello Nuclear Generating Plant St. Paul, Minnesota 55101-2127 l ATTN

Site Licensing l Northern States Power Company l 2807 West County Road 75 l Monticello, Minnesota 55362-9637 l Robert Nelson, President Minnesota Environmental Control Citizens Association (MECCA) 1051 South McKnight Road l St. Paul, Minnesota 55119 i

l Commissioner l l Minnesota Pollution Control Agency  ! 520 Lafayette Road St. Paul. Minnesota 55119 Regional Administrator, Region ill U.S. Nuclear Regulatory Commission l 801 Warrenville Road j- Lisle, Illinois 60532-4351 t Commissioner of Health Minnesota Department of Health 717 Delaware Street, S. E. Minneapolis, Minnesota 55440 Darla Groshens, Auditor / Treasurer Wright County Govemment Center 1 10 NW Second Street j Buffalo, Minnesota 55313

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January 1995 l

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s 1 ! REQUEST FOR ADDITIONAL INFORMATION RELATING TO LICENSE AMENDMENT REQUEST DATED JULY 26.1996 l SUPPORTING THE MONTICELLO NUCLEAR GENERATING PLANT L POWER RERATE PROGRAM (DOCKET NO. 50-263) l t Section 4.5.4 states that the increase in the radioactive source term caused by-operatirg at higher power levels results in a potential increase in the control room

operator dose. Explain what the " potential" increase is, and how it corresponds to the

_ existing allowable dose to the control room operators.

2. Section 4.5.4 states that the analysis inputs reflect changes to the emergency filtration train (EFT) system performance to compensate for the analysis method changes.

l Describe the " changes" to the EFT. l 3. Section B.3 states that the spent fuel pool (SFP) heat loads will slightly increase - resulting from plant operations at the proposed power level. Provide the following information:

a. Provide / compare the heat loads and corresponding peak calculated SFP l

temperatures (for plant operations at current power level and at proposed rerate power level) during planned refueling and unplanned full core offload. Single failure of the SFP cooling system does not need to be assumed for the unplanned full core offload.

b. Is full core offload the general practice for planned refuelings?

c. How many SFP cooling system trains will be available/ operable prjor to a planned refueling outaga or an unplanned full core offload?

l 4. In the unlikely event that there is a complete loss of SFP cooling capability, the SFP l water temperature will rise and eventually will reach boiling temperature. Provide the time to boil (from the pool high temperature alarm caused by loss-of-pool cooling) and the boil-off rate (based on the heat load for the unplanned full core offload scenario). Also, discuss sources and capacity of makeup water and the methods / systems (indicating system seismic design Category) used to provide the makeup water.

5. What is the maximum temperature that the fuel racks are designed for, and what temperature would the racks actually experience with power rerate?

6. Section 6.4.1.1.2 states that the heat loads for the shutdown cooling, suppression pool i

cooling, and emergency fuel pool cooling modes of operation are increased by power rerate. Providc the analysis to support this statement, and include the maximum spent fuel pool temperature that results from power rerate. l ENCLOSURE l

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7. In Section 6.6, for HVAC [ heating, ventitation, and air conditioning] that serves areas with condensate and feedwater lines or w:th lines that contain suppression pool water, provide the evaluation for the effect of the power rerate on the HVAC systems.

8. For Section 7.0, provide the analyses for the following:

j a. To assure that the turbines can pass the higher steam flow rates with adequate i design and pressure control. l b. To evaluate the performance of the moisture-separator reheater systems under j higher operating conditions. f c. To ensure that the main generator and its auxiliaries are capable of producing  ! higher electrical output while still meeting design requirements (include an l evaluation of the effect of the increased generator loads on the TBCCW [ turbine ! building component cooling water) system).

d. For the effect of power rerate on the feedwater pumps, feedwater heater drains, .

and the feedwater control valves. l [

9. Section 7.4 states that the feedwater system design pressure and temperature requirements have been evaluated for 1775 MWt [mega watts thermal] and are adequate for power rerate. Explain what is meant by " adequate."

10. Section 7.4 states that the feedwater regulating valves were originally designed for l greater than warranted flow conditions and are therefore adequate. What are the original design flows of the feedwater regulating valves, and how do they compare with the flow conditions that result from power rerate?

11. Section 7.4 states that the ASME Section Vill feedwater heaters will be analyzed and l verified to be acceptable for the slightly higher feedwater heater temperatures and l pressures for the 1775 MWt power rerate. What is the acceptability for power rerate l based on for the feedwater heaters now? What is the effect of the higher flow rates on l

~ the heaters? When are the feedwater heaters expected to be recertified for the higher temperature and pressures? What modifications are planned to ensure that adequate feedwater flow margin at 1775 MWt exists?

12. Section 10.1 states that the slight changes in feedwater, condensate, and RWCU

[reccior water cleanup] temperatures result in an insignificant increase in the mass and l energy release rates following high energy line breaks. Explain how ' insignificant" the l increase is, and how it correlates to the margin in the existing EQ [ environmental l qualification) envelopes. l

13. Section 10,1.1 states that GOTHIC was benchmarked against previously approved high energy line break analysis outputs, and the comparison results were found to be in close agreement. Explain what is meant by "close agreement." Was the output of GOTHIC compared to the previously approved EDSFLOW output using the same input assumptions? Are the GOTHIC results more or less conservative than EDSFLOW?

Provide the corresponding temperature, pressure, and humidity profiles that support the statement. L

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14. Section 10.1.1.1 states that the mass and energy release for the Main Steam Line Break (MSLB) outside containment was calculated using the SAFER /GESTR-LOCA model. Is this the same model that was used during the initial licensing of Monticello for MSLBs?

If not,' explain the differences between the models and any changes in assumptions.

15. Section 10.1.1.6 states that the Moody Slip break flow model was used to calculate the mass flux for the steam jet air ejector steam line break. Is this the same model that was used during the initial licensing of Monticello for the steam jet air ejector steam line break? If not, explain the differences between the models and any changes in assumptions.

16. What is the basis for stating that all equipment affected by the various line breaks discussed in Section 10.0, will remain qualified?

l 17. What testing will be performed on the feedwater and condensate systems prior to the implementation of power rerate?

18. For the slightly increased power rerate temperature and pressure conditions, do the non-metallic parts of non-electrical equipment / components (pumps, heat exchangers, etc.) continue to meet the following design and qualification requirements:

a. Components shall be designed to be compatible with the postulated environmental conditions, including those associated with LOCAs

[ loss-of-coolant accidents).

b. Measures shall be established for the solection and review for suitability of application of materials, parts, and equipment that are essential to safety-related functions.

c. Design control measures shall be established for verifying the adequacy of design.

d. Equipment qualification records shall be maintained and shall include the results of tests and materials analyses.

19. Describe the Monticello power rerate process. Describe in detail the extent of the NSP's oversight and independent review of the contractor work and the QA [ quality assurance) involvement in the power rerate process.

Provide a list of all engineering evaluation reports (i.e., transient analyses, pipe stress analysis, RPV [ reactor pressure vessel] stress report, system evaluation reports, analysis basis documents, etc.) that were completed to support the conclusions documented in Exhibit E of the license amendment request. For each report, indicate preparer (i.e., GE or NSP) and reviewer organization. Describe the process used to ensure accuracy of plant-specific input assumptions and acceptability of results.

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