ML18318A298

October 18, 2018 and October 23, 2018 Category 1 Public Teleconferences Summary Meeting to Discuss the Nuscale Power, LLC Responses to Requests for Additional Information Associated with the Nuscale Design Certification Application

ML18318A298
Person / Time
Site:	NuScale
Issue date:	11/16/2018
From:	Getachew Tesfaye NRC/NRO/DLSE/LB1
To:	Samson Lee NRC/NRO/DLSE/LB1
Tesfaye G X/NRO/8013
References
Download: ML18318A298 (8)

Text

November 16, 2018 MEMORANDUM TO: Samuel S. Lee, Chief Licensing Branch 1 Division of Licensing, Siting, and Environmental Analysis Office of New Reactors FROM: Getachew Tesfaye, Senior Project Manager /RA/

Licensing Branch 1 Division of Licensing, Siting, and Environmental Analysis Office of New Reactors

SUMMARY

OF THE OCTOBER 18, 2018 AND OCTOBER 23, 2018, CATEGORY 1 PUBLIC TELECONFERENCES TO DISCUSS THE NUSCALE POWER, LLC RESPONSES TO REQUESTS FOR ADDITIONAL INFORMATION ASSOCIATED WITH THE NUSCALE DESIGN CERTIFICATION APPLICATION The U.S. Nuclear Regulatory Commission (NRC) held Category 1 public teleconferences on October 18, 2018 and October 23, 2018, to discuss responses to the NRC staffs requests for additional information associated with the NuScale Power, LLC (NuScale) design certification application. Participants included personnel from NuScale. Members of the general public did not participate in these teleconferences.

The public meeting notices dated October 18, 2018 and October 23, 2018, can be found in the NRCs Agencywide Documents Access and Management Systems under Accession Nos.

ML18254A056 and ML18295A614. These meeting notices were also posted on the NRC public website.

Enclosed is the meeting agenda (Enclosure 1), list of participants (Enclosure 2), and overview (Enclosure 3).

Docket No.52-048

Enclosures:

1. Meeting Agenda

2. List of Attendees

3. Meeting Overview cc w/encl.: DC NuScale Power, LLC Listserv CONTACT: Getachew Tesfaye NRO/DLSE 301-415-8013

ML18318A298 NRO-002 OFFICE DLSE/LB1:PM DLSE /LB1:LA DLSE/RPAC DNRL/LB1:PM NAME GTesfaye MMoore EStutzcage

• GTesfaye (signed)

DATE 11/13/2018 11/15/2018 11/16/2018 11/16/2018 U.S. NUCLEAR REGULATORY COMMISSION CATEGORY 1 PUBLIC TELECONFERENCE TO DISCUSS THE NUSCALE POWER, LLC RESPONSES TO REQUESTS FOR ADDITIONAL INFORMATION ASSOCIATED WITH THE NUSCALE DESIGN CERTIFICATION APPLICATION MEETING AGENDA October 18, 2018 1:00 - 1:15 PM Introductions and Identification of topics 1:15 - 2:20 PM Discussion of U.S. Nuclear Regulatory Commission (NRC) Staffs Questions regarding NuScale Power LLCs (NuScale) Responses to Requests for Additional Information (RAI) Nos. 9264, 9281, 9161, and 9291.

2:20 - 2:30 PM Public Comments/Questions 2:30 PM Meeting Closure October 23, 2018 11:00 - 11:15 AM Introductions and Identification of topics 11:15 - 11:30 AM Discussion of NRC Staffs Questions regarding NuScales Responses to RAI Nos. 9264, 9281, 9161, and 9291.

11:30 - 11:40 AM Public Comments/Questions 11:40 - 01:00 PM Closed Portion Enclosure 1

U.S. NUCLEAR REGULATORY COMMISSION CATEGORY 1 PUBLIC TELECONFERENCE TO DISCUSS THE NUSCALE POWER, LLC RESPONSES TO REQUESTS FOR ADDITIONAL INFORMATION ASSOCIATED WITH THE NUSCALE DESIGN CERTIFICATION APPLICATION LIST OF ATTENDEES October 18, 2018 and October 23, 2018 Name Organization Getachew Tesfaye U.S. Nuclear Regulatory Commission (NRC)

Zachary Gran NRC Ronald LaVera NRC Michael Dudek NRC Edward Stutzcage NRC Jim Osborn NuScale Power, LLC (NuScale)

Jon Bristol NuScale Mark Shaver NuScale Enclosure 2

U.S. NUCLEAR REGULATORY COMMISSION OVERVIEW OF THE OCTOBER 18 AND 23, 2018, TELECONFERENCE TO DISCUSS THE NUSCALE POWER, LLC RESPONSES TO REQUESTS FOR ADDITIONAL INFORMATION ASSOCIATED WITH THE NUSCALE DESIGN CERTIFICATION APPLICATION The purpose of this teleconference was to discuss the results of the U.S. Nuclear Regulatory Commission (NRC) staffs review of NuScale Power LLCs (NuScale) responses to Requests for Additional Information (RAI) Nos. 9264, 9281, 9161, and 9291.

The following is the summary of the NRC staffs feedback and agreed upon next steps for the resolution of the remaining issues.

1. RAI No. 9264, Question 12.02-4:

a. NRC Staff Feedback: In Design Control Document (DCD) Revision 1, the pool surge control (PSC) Surge Tank activities provided in Tables 12.2-10 and the related PSC Surge Tank photon spectra in DCD Table 12.2-11 did not appear to consider the operation of the pool cleanup system (PCUS) demineralizer.

However, in the response to RAI No. 9270, Question 12.02-20, NuScale revised Table 12.2-10, and in RAI No. 9264, Question 12.02-4 NuScale revised Table 12.2-11, based on changes to the design basis failed fuel fraction (DBFFF) and other changes. In the new source terms, NuScale appears to consider operation of the PCUS demineralizer in calculating the activities in the PSC Surge Tank.

However, while NuScale revised Table 12.2-9 (which provides source term assumptions for the demineralizer and surge tank), in the response to RAI No.

9264, Question 12.02-4, the revised table does not provide any information on the decontamination factors assumed for the PCUS demineralizer. The NRC staff notes that the applicant has provided the decontamination factors for other demineralizers in the DCD such as Chemical and Volume Control System (CVCS) demineralizers and liquid radwaste management system demineralizers, which is consistent with providing the methods, models, and assumptions for source terms, as described in the Design-Specific Review Standard (DSRS).

Please update the response to provide the decontamination factors for the PCUS in DCD Table 12.2-9.

b. Next Step: NuScale explained that the information the NRC staff is looking for is in DCD Chapter 11, Table 11-2-4. The NRC staff was satisfied with the explanation, no further action is needed.

2. RAI No. 9281, Question 12.03-56:

a. NRC Staff Feedback: In the response to RAI 9281, Question 12.03-56, NuScale provided revised radiation zone maps for the reactor building. Also, in the response to RAI No. 9297, Question 12.03-59, the NuScale indicated that Room

1. 010-022 is not a location that personnel access and the area is not used for equipment qualification, so the radiation zoning for that area was removed from 1

Enclosure 3

the radiation zone figures. Is there any need to access the front faces of the bioshield to inspect or perform work? Or isnt there any other work that may require a worker to access Room #010-022.

b. Next Step: NuScale confirmed that there is no need to access the front faces of the bioshield to inspect or perform work and there isnt any other work that may require a worker to access Room #010-022. NuScale also stated that they are in the process of redesigning the removable damper and took action to reevaluate the radiation zone maps for any impact.

3. RAI No. 9281, Question 12.03-56:

a. NRC Staff Feedback: In the response to RAI No. 9281, Question 12.03-56, there are numerous other areas, besides Room #010-022 where the radiation zoning does not appear to be labeled or it is unclear what the radiation zoning is. This includes much of Figure 12.3-1b, which includes the pool cleanup filter rooms at that elevation and portions of Figure 12.3-1d. A few of these areas appeared more clearly labeled in Revision 1 of the DCD. Some of the areas appear to simply be the upper portion of rooms that are labeled on the lower elevation, however, it is not clear that the zoning is intended to be the same as that shown on the lower elevation. Will the zoning be more clearly defined for the reactor building in DCD Revision 2? Are there other areas in the reactor building (besides room #010-022) where the radiation zoning has been intentionally left blank, removed, or not labeled? If so, please explain why.

b. Next Step: NuScale stated there other are no areas in the reactor building (besides room #010-022) where the radiation zoning has been intentionally left blank, removed, or not labeled. NuScale further stated that the radiation zoning for the upper elevations are based on the access point in the lower elevation.

The NRC staff was satisfied with the explanation, no further action is needed.

4. RAI No. 9281, Question 12.03-56:

a. NRC Staff Feedback: A revised degasifier source term has not been provided in any of the RAI responses. However, NuScale has indicated that the revised degasifier source term will be provided in Revision 2 of the DCD. Do the radiation zone maps provided in the response to RAI No. 9281, Question 12.03-56, include consideration of the updated degasifier source terms or are they based on the old degasifier source terms?

b. Next Step: NuScale confirmed that the radiation zone maps provided in the response to RAI No. 9281, Question 12.03-56, include consideration of the updated degasifier source terms. NuScale took action to identify the appropriate RAI no. to supplement to address the degasifier source term information that is not incorporated in Rev 2. NuScale also informed the NRC staff that they have found an error in the modeling of the airborne concentration in the pool room.

The correction to the error was not incorporated in Rev 2 of the DCD. NuScale committed to provide a supplemental response to RAI No. 9270, Question 12.02-20 to provide FSAR markup that will be incorporated in Rev 3 of the DCD.

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5. RAI No. 9161, Question 11.01-1:

a. NRC Staff Feedback: As part of the response to RAI No. 9161, Question 11.01-1 NuScale provided revisions to Table 12.2-3, Cold Leg Primary Coolant Gamma Source Term, and Table 12.2-4, Near Core Primary Coolant Gamma Source Term. During the DBFFF Audit, the NRC staff was able to confirm the photon emission rates for Table 12.2-4, however, the staff was not able to confirm the photon emission values provided for Table 12.2-3. The NRC staff expected the values in Table 12.2-3 to change as a result of the change in the DBFFF. The staff also considered the change in N-16 concentrations as a result of the increased primary coolant flow rate.

• Describe all of the factors used to change DCD Rev. 1 Table 12.2-3 into RAI No. 9161 Table 12.2-3.

• What are the basis for the factors used to derive RAI No. 9161 Table 12.2-3? If there are changes other than to the DBFFF and the PCS flowrate, then tell us where in the DCA they are discussed.

• What is Table 12.2-3 used for?

• Does the Monte Carlo N-Particle Transport Code (MCNP) calculation for determining the dose rate at the top of the reactor vessel inside of the containment vessel consider photon leaving the reactor vessel at or near the reactor vessel region below the steam generators?

b. Next Step: NuScale stated that the information in Table 12.2-3 is used in shielding calculation for the module. The basis for Table 12.2-3 in RAI No. 9161 response is the very early version of primary coolant source that has far more isotopes than what was reported. In the revised source term the number of isotope were reduced and the N-16 source term value is increased.

6. RAI No. 9161, Question 11.01-1:

a. NRC Staff Feedback: Regarding the revisions to Table 12.2-1 in the response to RAI No. 9161, Question 11.01-1, please clarify what is meant by near core fraction of primary coolant (27 percent) and cold leg fraction of primary coolant (73 percent).

b. Next Step: The applicant indicated that the near the core source term applied to the coolant leaving the core and in the lower and upper riser region and the cold leg source term includes the pressurizer region and steam generator region.

Based on the information NuScale provided in the 10/18/2018 public teleconference related to this response and the response to other items related to N-16 concentrations, the NRC staff modeled the dose rates above the reactor vessel. The NRC staff was getting significantly higher dose values from what NuScale provided to the NRC staff. Specifically, if the NRC staff assumes the concentration of N-16 that NuScale indicated would be in the pressurizer liquid, as NuScale explained during the 10/18/2018 teleconference and model the dose inside containment, above the reactor vessel, the NRC staff was getting a dose rate of about 1,500 mrem/hour (that is from just N-16 in the pressurizer liquid alone), in addition to this, the NRC staff gets over 100 mrem/hour more above the reactor vessel from the fluid below the pressurizer from just N-16. However, 3

in the response to RAI No. 9291, Question 12.02-24, NuScale indicates that the dose rate inside containment, above the reactor vessel from reactor coolant (which NuScale accounts for not only N-16 but all the other radionuclides) is only 1.1 mrem/hour. Staff didnt understand why they are getting such a significant difference. Therefore, the NRC staff requested NuScale to discuss in more detail the assumptions NuScale is making in doing this calculation. For example, what is NuScale assuming for shielding above the pressurizer fluid? The goal of the meeting is to gain a better understanding of NuScales assumptions, so that NRC staff can come to an understanding of how the value of 1.1 mrem/hour was obtained and to determine the acceptability of gamma doses above the reactor vessel.

In the 10/23/2018 portion of the teleconference, NuScale indicated that the dose rate of 1.1 mrem/hour provided in the response to RAI No. 9291, Question 12.02-24 did not reflect the updated reactor coolant source term which includes consideration of N-16 in the coolant and an increased reactor coolant flow rate, including N-16 in the pressurizer. The applicant indicated that while the N-16 concentrations were revised in Revision 1 of the DCD, the resulting dose rate changes were not reflected in the response to RAI No. 9291, Question 12.02-24 or DCD Table 3C-6. The applicant indicated that dose rate using the revised assumptions were similar to values that the staff calculated. The applicant agreed to update the response to RAI No. 9291, Question 12.02-24 to update the dose rate information and to provide the appropriate DCD revisions.

7. RAI No. 9291, Question 12.02-24:

a. NRC Staff Feedback: DCD Table 12.2-5 provides N-16 concentrations at the core exit, the entrance to the steam generators, and in the CVCS letdown line. In addition, the response to RAI No. 9291, Question 12.02-24 indicates that N-16 was considered to be transported through the reactor coolant in evaluating doses in and around containment (including above the top of the pressurizer).

However, DCD Section 12.2.1.2, specifies that because of the flow velocity of the primary coolant, the short-lived isotopes (half-life <10 seconds) are not considered to be present in the steam generator region or the reactor down comer region. N-16 has a half-life of less than 10 seconds. In addition, Section 12.2.1.2 states that the modeling simplification described, of not modeling N-16 in the steam generator region or the reactor down coming region is conservative.

It is unclear why it is conservative to not consider N-16 in the steam generator region or the reactor down comer region. Wouldnt it be more accurate to state that because the gamma dose is dominated by neutron induced gammas in these areas, the N-16 dose is negligible? Please correct these statements in the DCD. (Note: this question is not requesting NuScale to revise calculations, only to explain and/or correct the wording in DCD Section 12.2.1.2).

b. Next Step: NuScale stated, similar to Item 4 above for degasifier, FSAR Rev. 2 has the updated information but the response to RAI No. 9291, Question 12.02-24 had not been updated to revise the text in DCD Section 12.2.1.2 associated with the changes made to DCD Table 12.2-3 and 12.2-4 source terms. NuScale committed to provide supplemental response to RAI No. 9291, Question 12.02-24 to provide the updated information.

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