ML18172A320

LLC Response to NRC Request for Additional Information No. 431 (Erai No. 9412) on the NuScale Design Certification Application

ML18172A320
Person / Time
Site:	NuScale
Issue date:	06/21/2018
From:	Wike J NuScale
To:	Document Control Desk, Office of New Reactors
References
RAIO-0618-60594
Download: ML18172A320 (6)

Text

RAIO-0618-60594 June 21, 2018 Docket No.52-048 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk One White Flint North 11555 Rockville Pike Rockville, MD 20852-2738

SUBJECT:

NuScale Power, LLC Response to NRC Request for Additional Information No.

431 (eRAI No. 9412) on the NuScale Design Certification Application

REFERENCE:

U.S. Nuclear Regulatory Commission, "Request for Additional Information No.

431 (eRAI No. 9412)," dated April 23, 2018 The purpose of this letter is to provide the NuScale Power, LLC (NuScale) response to the referenced NRC Request for Additional Information (RAI).

The Enclosure to this letter contains NuScale's response to the following RAI Question from NRC eRAI No. 9412:

14.03.09-4 This letter and the enclosed response make no new regulatory commitments and no revisions to any existing regulatory commitments.

If you have any questions on this response, please contact Steven Mirsky at 240-833-3001 or at smirsky@nuscalepower.com.

Sincerely, ennie Wike Jennie Manager, Licensing NuScale Power, LLC Distribution: Gregory Cranston, NRC, OWFN-8G9A Omid Tabatabai, NRC, OWFN-8G9A Samuel Lee, NRC, OWFN-8G9A : NuScale Response to NRC Request for Additional Information eRAI No. 9412 NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvalis, Oregon 97330, Office: 541.360.0500, Fax: 541.207.3928 www.nuscalepower.com

RAIO-0618-60594 :

NuScale Response to NRC Request for Additional Information eRAI No. 9412 NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvalis, Oregon 97330, Office: 541.360.0500, Fax: 541.207.3928 www.nuscalepower.com

Response to Request for Additional Information Docket No.52-048 eRAI No.: 9412 Date of RAI Issue: 04/23/2018 NRC Question No.: 14.03.09-4 10 CFR 52.47(a)(2) requires that a standard design certification application include a final safety analysis report (FSAR) that describes the design of the facility including the principal design criteria for the facility, for which NuScale used the 10 CFR Part 50, Appendix A, "General Design Criteria for Nuclear Power Plants." General Design Criterion (GDC) 19 requires, in part, that equipment is provided at appropriate locations outside the control room (1) with a design capability for prompt hot shutdown of the reactor, including necessary instrumentation and controls to maintain the unit in a safe condition during hot shutdown, and (2) with a potential capability for subsequent cold shutdown of the reactor through the use of suitable procedures.

NuScale DCD Tier 2, Section 1.2.2.1, Main Control Room, states that in the event that the Main Control Room (MCR) becomes uninhabitable, a remote shutdown station in the Reactor Building provides a secondary location for safe shutdown of the reactors.

10 CFR 52.47(b)(1) requires a design certification application to contain the proposed inspections, tests, analyses, and acceptance criteria (ITAAC) that are necessary and sufficient to provide reasonable assurance that, if the inspections, tests, and analyses are performed and the acceptance criteria met, a plant that incorporates the design certification is built and should operate in accordance with the design certification, the provisions of the Atomic Energy Act, and the NRC's regulations.

The letter from the NRC to NuScale dated April 8, 2016 (ML16096A121), contained a set of draft standard ITAAC that could be used in the NuScale Design Certification Application.

Standard ITAAC No. I-22 pertains to the Main Control Room (MCR) and Remote Shutdown Station (RSS) displays and alarms for various systems. Standard ITAAC No. I-23 pertains to plant system controls at the operator workstation in the MCR and RSS. The standard ITAAC do not specify which displays, alarms, and controls that should be verified by ITAAC No. I-22 and I-23.

NuScale DCD Tier 1, Table 2.5-7, Module Protection System and Safety Display and Indication System ITAAC, identifies the displays, alarms, and controls that NuScale has selected to be verified by ITAAC. The staff would like to understand the basis for selecting ITAAC to verify the displays, alarms and controls listed in DCD Tier 1, Table 2.5-7, and why there are no ITAAC to verify any displays, controls or alarms in the RSS.

NuScale Nonproprietary

Please explain the basis for selecting ITAAC to verify the displays, alarms, and controls listed in DCD Tier 1, Table 2.5-7, and also why the ITAAC does not verify any displays, controls and alarms at the RSS.

NuScale Response:

NuScale developed a set of criteria for selecting controls, displays, and alarms to be verified by ITAAC. However, as described in Tier 2, Section 15.0.0.6.4, there are no operator actions credited in the evaluation of NuScale design basis events. As such, there is no inventory of controls, displays, and alarms required to mitigate the consequences of design basis events or to restore safety functions. The ITAAC to verify displays, alarms, and controls are described in Table 1, Table 2 and Table 3 below by specific criteria. The criteria for selection of which controls, displays, and alarms in the NuScale design are verified with ITAAC are as follows:

Manual actuation of safety-related systems or functions (Table 1)

Module protection system (MPS) status (Table 1)

Critical safety functions (post-accident monitoring (PAM) Type B variable display) and fission product barrier status (PAM Type C variable display) (Table 2)

Performance of important human actions (IHAs) which are for beyond design bases events (Table 3)

The NuScale ITAAC in Tables 1, 2, and 3 are all contained in Tier 1 Table 2.5-7. Tables 1, 2, and 3 identify the correlation between standardized ITAAC and NuScale ITAAC related to controls, displays, and alarms. The standardized ITAAC are described in the enclosure to the letter from the NRC to NuScale dated April 8, 2016 (ML16097A132).

Table 1: ITAAC MPS Manual Actuation of Safety-Related Systems or Functions and MPS Status Standardized Associated NuScale ITAAC Number and Design Feature Verified ITAAC Number Description 02.05.12 MPS Manual Reactor Trip I11 Verifies manual actuation of a reactor trip Actuation via MPS switches in the MCR.

02.05.13 MPS Manual ESF I12 Verifies manual actuation of ESF functions Equipment Actuation via MPS switches in the MCR.

02.05.22 Verifies MCR indication of MPS manual or automatic operational bypasses.

I19 MPS Bypass Indication 02.05.23 Verifies MCR indication of MPS maintenance bypasses.

NuScale Nonproprietary

02.05.24 MPS Self-Testing I21 Verifies indications and alarms for MPS Features self-test failures.

Table 2 Introduction As discussed in Tier 2, Section 7.1.1.2.2, post-accident monitoring of PAM Type B and Type C variables are nonsafety-related functions. The NuScale design has no Type A variables because there no operator actions credited in any Chapter 15 anticipated operational occurrence, infrequent event, or accident, nor for the station blackout or anticipated transient without scram (ATWS) analysis. Since the NuScale design has Type B and Type C variables, as shown in Tier 2, Table 7.1-7 and Tier 2, Figure 7.1-2, all PAM Type B and Type C variables are monitored by the MPS and are displayed on the SDIS.

Table 2: ITAAC Related to Critical Safety Function and Fission Product Barrier Status Standardized Design Feature Associated NuScale ITAAC Number and ITAAC Number Verified Description 02.05.25 PAM B and Type C Verifies PAM Type B and Type C displays I22 displays and alarms. are retrieved and displayed on the SDIS displays in the MCR.

Table 3 Introduction Tier 2, Section 18.6.3 describes two important human actions (IHA) identified from the human reliability analysis for beyond design basis events. Both IHAs are conducted from the main control room.

The first IHA is for the operator to un-isolate the containment and initiate injection of coolant inventory into the reactor vessel using the chemical and volume control system following incomplete emergency core cooling system actuation during a loss of coolant inside containment, or a loss of coolant outside containment in conjunction with the failure of the associated containment isolation valves.

The second IHA is for the operator to un-isolate the containment and initiate injection of coolant inventory into the containment vessel using the containment flooding and drain system if the chemical and volume control system is unavailable during a loss of coolant outside containment in conjunction with the failure of the associated containment isolation valves.

Tier 1, Table 2.5-6: describes the IHA Controls.

NuScale Nonproprietary

Table 3: ITAAC Related to Important Human Actions (for Beyond Design Bases Events)

Standardized ITAAC Design Feature Associated NuScale ITAAC Number and Number Verified Description 02.05.26 I23 IHA controls Verifies the MCR controls that implement IHAs.

Summary ITAAC are not designed to address all aspects of design, including the remote shutdown station (RSS) HSI. Tier 2, Section 7.2.13.3, states there is no manual control of safety-related equipment from the RSS HSI. In addition, there are no IHAs performed from the RSS. The RSS contains MCS and PCS displays as well as MCS and PCS controls identical to the main control room MCS and PCS displays and controls which do not control safety-related equipment. The RSS displays and provides an alternate location for the operator to monitor the plant operation if evacuation of the MCR is required.

An MCR evacuation occurrence is not postulated to occur simultaneously with any DBE, nor does it cause fuel damage, or result in consequential loss of function of the reactor coolant pressure boundary or primary containment barriers. As described in Section 7.1.1.2.3, at the onset of an MCR evacuation, the operators trip the reactors and initiate decay heat removal and containment isolation for each reactor prior to leaving the MCR. These actions place and maintain the NPM in a safe state. Following evacuation of the MCR, the ability to isolate the MPS manual actuation switches to prevent spurious actuations is provided in the RSS, as described in Section 7.2.12. The location of these switches is verified by ITAAC 02.05.29.

On the basis of the above, there are no ITAAC for RSS HSI displays, alarms, or controls.

Impact on DCA:

There are no impacts to the DCA as a result of this response.

NuScale Nonproprietary