NMP1L3281, Supplemental Information to Support Review of License Amendment Request to Revise Technical Specifications 3.3.1 for Primary Containment Oxygen Concentration

From kanterella
Jump to navigation Jump to search

Supplemental Information to Support Review of License Amendment Request to Revise Technical Specifications 3.3.1 for Primary Containment Oxygen Concentration
ML19137A070
Person / Time
Site: Nine Mile Point Constellation icon.png
Issue date: 05/17/2019
From: Jim Barstow
Exelon Generation Co
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
EPID L-2018-LLA-0183, NMP1L3281
Download: ML19137A070 (10)
v • d • e


Text

200 Exelon Way Exelon Generation . Kennett Square . PA 19348 www exeloncorp com 10 CFR 5090 NMP1L3281 May 17, 2019 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Nine Mile Point Nuclear Station, Unit 1 Renewed Facility Operating License No. DPR-63 NRC Docket No. 50-220

Subject:

Supplemental Information to Support Review of Nine Mile Point Nuclear Station, Unit 1, License Amendment Request to Revise Technical Specifications 3.3.1 for Primary Containment Oxygen Concentration

References:

1. Letter from J. Barstow (Exelon Generation Company, LLC) to U.S. Nuclear Regulatory Commission, "License Amendment Request-Revise Technical Specifications 3.3.1 for Primary Containment Oxygen Concentration," dated June 26, 2018
2. Email from M. Marshall (Senior Project Manager, U.S Nuclear Regulatory Commission) to R. Reynolds (Exelon) , "Nine Mile Point, Unit 1-Request for Additional Information Regarding Primary Containment Oxygen Concentration License Amendment request (L-2018-LLA-0183)," dated January 25, 2019
3. Letter from J. Barstow (Exelon Generation Company, LLC} to U.S. Nuclear Regulatory Commission, "Response to Request for Additional Information by the Office of Nuclear Reactor Regulation to Support Review of Nine Mile Point Nuclear Station, Unit 1, License Amendment Request to Revise Technical Specifications 3.3.1 for Primary Containment Oxygen Concentration," dated February 25, 2019
4. Public Meeting Notice for April 18, 2019, "Meeting Between NRC and Exelon Generation Company, LLC (Exelon) Concerning the Nine Mile Point Nuclear Station, Unit 1, Oxygen Concentration License Amendment Request," dated April 5, 2019 By letter dated June 26, 2018 (Reference 1), Exelon Generation Company, LLC (Exelon) requested to change the Nine Mile Point Unit 1 (NMP1) Technical Specifications (TS). The

U.S. Nuclear Regulatory Commission Supplemental Information Primary Containment Oxygen Concentration Docket No. 50-220 May 17, 2019 Page 2 proposed License Amendment Request (LAR) is to revise Technical Specifications 3.3.1 for Primary Containment Oxygen Concentration.

On January 25, 2019 (Reference 2), the U.S. Nuclear Regulatory Commission (NRC) identified areas where additional information was necessary to complete the review.

On February 25, 2019 (Reference 3), Exelon submitted responses to the NRC's request for additional information.

A public meeting was held on April 18, 2019 (Reference 4), where the NRC staff and representatives of Exelon discussed Exelon's responses to the NRC's request for additional information concerning the Nine Mile Point Nuclear Station, Unit 1, oxygen concentration license amendment request. An additional public meeting was held on May 9, 2019 to present the planned submittal information to ensure all NRC questions were appropriately addressed. to this letter contains supplemental information to support the NRCs review of the LAR. Attachment 2 to this letter contains the revised marked-up TS and Bases pages, replacing the previously submitted marked-up TS and Bases pages and associated inserts submitted with References 1 and 3.

Exelon has reviewed the information supporting a finding of no significant hazards consideration and the environmental consideration provided to the NRC in Reference 1. The supplemental information provided in this letter does not affect the bases for concluding that the proposed license amendment does not involve a significant hazards consideration. Furthermore, the supplemental information provided in this letter does not affect the bases for concluding that neither an environmental impact statement nor an environmental assessment needs to be prepared in connection with the proposed amendment.

There are no commitments contained in this response.

If you should have any questions regarding this submittal, please contact Ron Reynolds at 610-765-5247.

I declare under penalty of perjury that the foregoing is true and correct. Executed on the 171t1 day of May 2019.

James Barstow Director - Licensing & Regulatory Affairs Exelon Generation Company, LLC : Supplemental Information

U.S. Nuclear Regulatory Commission Supplemental Information Primary Containment Oxygen Concentration Docket No. 50-220 May 17, 2019 Page 3 : Revised Markup Pages cc: USNRC Region I Regional Administrator w/attachments USN RC Senior Resident Inspector - NMP "

USNRC Project Manager, NRR - NMP "

A. L. Peterson, NYSERDA "

ATTACHMENT 1 Nine Mile Point Nuclear Station, Unit 1 Renewed Facility Operating License No. DPR-63 NRC Docket No. 50-220 Supplemental Information

Supplemental Information Attachment 1 Primary Containment Oxygen Concentration Page 1 of 1 Docket No. 50-220 The original proposal and the response to Request for Additional Information to revise Limiting Condition for Operation (LCO) 3.3.1, Specifications a through d, are superseded by this supplemental information . The change to this LCO defines a specific period when the containment is not inert to accommodate transitory conditions during startup, shutdown and maintenance activities. This supplemental information supersedes the previous Technical Specifications (TS) marked up pages and associated TS Bases pages. The following changes described below are not intended to be all inclusive, but examples of the types of activities that would be performed:

Specification 3.3.1.a requires that the primary containment must be inert when the reactor is in the power operating condition, since this is the condition with the highest probability of an event that could produce hydrogen. The power operating condition is defined in the current NMP1 TS, Section 1.

Specification 3.3.1.b allows a 72-hour period when the containment is not inerted to accommodate transitory conditions during startup, shutdown and maintenance activities. The 72-hour period is a reasonable amount of time and is based on 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> to de-inert containment prior to shutdowns or in preparation for maintenance, 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> to perform work inside containment and 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> to re-inert. These time frames are based on industry operating experience and are considered reasonable.

The 72-hour period is based on operating experience for startup, maintenance, and shutdown conditions. For startup, typical operational items considered include the time to transition through startup and to place the mode switch into the "run" position. The transition period prior to entering the mode of applicability requires this time frame to include associated inspections, post maintenance test activities, and potential maintenance work inside the drywell while raising primary system temperature and pressure.

For maintenance activities during mid cycle, the 72-hour period allows for de-inerting containment, power reduction , troubleshooting, work preparations, repairs, post maintenance testing and containment re-inerting along with power restoration . Since the plant is in the "run" mode, it will remain in the mode of applicability for LCO 3.3.1.b throughout the maintenance activities. Therefore, the plant has a total of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to return the containment oxygen concentration back to within specifications.

For shutdown, activities include preparations for initial inspections to validate outage work scope, and the time to transition from "run" mode to the shutdown condition, without requiring a scram and the associated transients on the reactor and various systems.

Specification 3.3.1.c allows for 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> to exit the power operating condition , which is in alignment with the Standard Technical Specification (NUREG-1433) convention to change modes to the shutdown condition- hot.

ATTACHMENT 2 Nine Mile Point Nuclear Station, Unit 1 Renewed Facility Operating License No. DPR-63 NRC Docket No. 50-220 Revised Markup Pages TS Marked-up Pages 124 125 TS Bases Marked-up Pages (for information only) 126

LIMITING CONDITION FOR OPERATION SURVEILLANCE REQUIREMENT 3.3.1 OXYGEN CONCENTRATION 4.3.1 OXYGEN CONCENTRATION Accllcabllitv: Appllcabilitv=

Applies to the limit on oxygen concent~ra_t_ io_

n_wi

_*th

_ ln_ __.__ __ __, Applies to the periodic testing requirement for the the primary containment system. in the power primary containment system oxygen concentration.

Ob!ecliye: ~ opera t'mg con d't' 1 ion Oblectjve:

To assure that In the event of a loss-of-coolant To assure that the oxygen concentration within the accident any hydrogen generation will not result In a primary containment system Is within required limits.

combustible mixture within the primary containment system.

Soecification: Scectf!catlon:

a. The primary containment atmosphere shall be In accordance with the SurveRlance Frequency reduced lo less than four percent by volume Control Program, oxygen concentration shall be oxygen co~centration with nitrogen gas ~ determined.

~*B1111ii*1:1;i; eAll IAe Feaeter 111 il'I the-~;,;;~, ~ while in the power BjleFaliRll eeAllille11, except as specified in "b" ...._ t' d't' and "c" below. Opera mg con I IOn AMENDMENT NO. ~. 222 124

LIMmNG CONDITION FOR OPERATION SURVEILLANCE RE UIREMENT while in the power If the containment oxygen concentration is greater than or equal to the four percent by operating condition volume limit; except es 111lle1Jed a1:1flAg elaFt!l11 and for transitory and a~* "down in "b" abo 1 "'1, restore the oxygen concentration to with 1~1t within -a4 hours. conditions during 1

If Specifications *a,"~ above are~ startup, shutdown me~ t ~>f81Hl1E~il&IE!ft'19'e!!!t111~1'1trit-be and maintenance activities exit the power operating condition within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.

AMENDMENT NO. 44a, 185 125

the 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> period for these infrequently performed evolutions BASES FOR 3.3.1AND4.3.1 OXYGEN CONCENTRATION The four percent by volume oxygen concentration eliminates the possibility of hydrogen combustlon following a loss-of-coolant accident (Section Vll-G.2.0 and Appendix E*ll.5.2)". The only way that significant quantities of hydrogen could be generated by metal-water reaction would be if the core spray system failed to sufficiently cool the core. As discussed in Section Vll-A.2.0". each core spray system will deliver, as a minimum, core spray sparger flow as shown on Figure vu-2*. In addition to hydrogen generated by metal-water reaction significant quanUtles can be generated by radlotysls. (Technical Supplement to Petition for Conversion from Provisional Operating Licen e to Full Term Operating License).

lnertlng the primary conlainment Is an operational problem because it prevents containment access without an appropriate breathing apparatus. Therefore, the primary containment Is inerted as late as possible In the plant startup and deinerted as soon as possible in plant shutdown. The probability of an event that generates hydrogen occurrlng within 11\a li1'91 24 l'leHrs ef 11 Bls!tltl', er ~within lhe ~

laat 24 l'leH1'9 l!efere 111 sl'lt11deor1, Is low enough that these "windows," when the primary containment Is not lnerted, are also justified. Th is

!4 11001 time pe1 iod is a reasonable amount of time to allow plant personnel to perform i rting or delnertlng. ..--------.

activities that do not require

...___. shutdown conditions ,

including At reactor pressures s1g or less, the reactor will have been shutdown for more than an hour and the decay be at sufficient! ues so that fuel rods will be completely wetted by core spray. The fuel clad temperatures would not exce watersaturationtemperatureofabout344°F. ( !INSERT A The primary containment is normally slightly pressurized during periods of reactor operation. Nitrogen used for inertlng could leak out of the containment but air could not leak in to Increase the oxygen concentration. Once the containment Is filled with nitrogen to the required concentration, no monitoring of oxygen concentration is necessary. The Surveillance Frequency Is controlled under the Surveillance Frequency Control Program.

  • FSAR AMENDMENT NO.~. Revision 11 (0.185), 41 (A222) 126

Supplement to NMP1 02 Concentration Change INSERT A All nuclear reactors must be designed to withstand events that generate hydrogen either due to the zirconium metal water reaction in the core or due to radiolysis. The primary method to control hydrogen is to inert the primary containment. With the primary containment inert, that is, oxygen concentration less than 4.0 percent by volume, a combustible mixture cannot be present in the primary containment for any hydrogen concentration. An event that rapidly generates hydrogen from zirconium metal water reaction will result in excessive hydrogen in primary containment, but oxygen concentration will remain less than 4.0 percent by volume and no combustion can occur.

Specification 3.3.1.a requires that the primary containment must be inert when the reactor is in the power operating condition, since this is the condition with the highest probability of an event that could produce hydrogen.

Specification 3.3.1.b allows a 72-hour period when the containment is not inerted to accommodate transitory conditions during startup, shutdown and maintenance activities. The 72-hour period is a reasonable amount of time and is based on 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> to de-inert containment prior to shutdowns or in preparation for maintenance, 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> to perform work inside containment and 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> to re-inert. These time frames are based on industry operating experience and are considered reasonable.

Specification 3.3.1.c allows for 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> to exit the power operating condition, which is in alignment with the Standard Technical Specification (NUREG-1433) convention to change modes to the shutdown condition- hot.

Retrieved from "https://kanterella.com/w/index.php?title=NMP1L3281,_Supplemental_Information_to_Support_Review_of_License_Amendment_Request_to_Revise_Technical_Specifications_3.3.1_for_Primary_Containment_Oxygen_Concentration&oldid=1909160"