ML20006G700

Proposed Recommendation for ACRS Review of NuScale Power, LLC, Design Certification Application - Safety Evaluation with No Open Items for Chapter 12, Radiation Protection

ML20006G700
Person / Time
Site:	NuScale
Issue date:	12/19/2019
From:	David Petti Advisory Committee on Reactor Safeguards
To:	Riccardella P Advisory Committee on Reactor Safeguards
Snodderly, M, ACRS
Shared Package
ML20006G325	List: ML20006G420 ML20006G489 ML20006G575 ML20006G700
References
Download: ML20006G700 (4)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION ADVISORY COMMITTEE ON REACTOR SAFEGUARDS WASHINGTON, DC 20555 - 0001 December 19, 2019 MEMORANDUM TO: Peter Riccardella, Chairman Advisory Committee on Reactor Safeguards FROM: David Petti, Member /RA/

NuScale Subcommittee Advisory Committee on Reactor Safeguards

SUBJECT:

PROPOSED RECOMMENDATION FOR ACRS REVIEW OF NUSCALE POWER, LLC, DESIGN CERTIFICATION APPLICATION - SAFETY EVALUATION WITH NO OPEN ITEMS FOR CHAPTER 12, RADIATION PROTECTION In response to the Committees request, I have reviewed the NRC staffs safety evaluation report (SER) with no open items for Chapter 12, Radiation Protection, dated November 15, 2019 (ML19318E303). This memo documents my recommended course of action concerning further review of this chapter of the design certification application (DCA) and the staffs associated safety evaluation.

SER Phase 4 Summary Chapter 12 of the SER documents the staffs review of Revision 2 of Chapter 12, Radiation Protection, of the NuScale DCA , Part 2, Final Safety Analysis Report (ML18310A326).

Chapter 12 discusses four aspects of radiation protection: 1) assuring that occupational radiation exposures are as low as reasonably achievable; 2) determining projected radiation sources during normal operations, anticipated operational occurrences, and accident conditions; 3) establishing radiation protection design features (shielding, ventilation, radioactivity monitoring systems, and contamination controls); and 4) providing the basis for the dose assessment for normal operation and post-accident sampling and analysis. Operational considerations on the implementation of a radiation protection program are also included but outside the scope of the DCA review and will be addressed by a combined license (COL) applicant.

The Phase 2 SER for this chapter (ML19015A137) identified open items which NuScale has addressed through information submitted on the docket. All the open items have been satisfactorily closed. In addition, the Phase 2 SER for this chapter identified confirmatory items with proposed changes submitted on the docket, which the staff found acceptable.

D. Petti In several cases, NuScale stated that they did not intend to revise Tier 1 Chapter 4 of the application to include design interface items or to complete the design. Therefore, the NRC staff has recommended that the Commission include language in the proposed rule clarifying that the NRC is not making a finding on the adequacy of those parts of the design to achieve the safety function of limiting offsite and onsite dose. Specifically, these items are:

• Radiation shielding for the Nuclear Power Module (NPM) to Reactor Building Steam Gallery penetrations; and

• Design features and analysis for leakage of systems outside of containment (containment evacuation system, containment flood and drain system, and post-accident sampling system) used for combustible gas monitoring, that may have highly radioactive fluid following an accident.

If adopted by the Commission, these items will need to be addressed by a future combined license (COL) applicant.

Applicable Concerns from ACRS Phase 3 Letter Report Our letter noted there are potentially risk-significant items in the NuScale design that are not yet fully developed and recommended that requirements be included in the DCA to ensure that the licensed NuScale plant will perform as credited. We observed that there are numerous COL Items identified in Chapter 12 and we stated that it is important that NuScale provide sufficient information regarding how such requirements should be met.

We observed that this is particularly important when the DCA credits such design features.

Our letter also identified several issues, such as post-shutdown crud burst; resin transfer piping sizes; RCS flow rate changes; radiation fields around the top of the containment vessel; source term and related information during degasifying reactors for shutdown; and ultimate heat sink pool temperature assumptions for airborne activity source terms.

Many of these issues were addressed by the applicant in subsequent interactions with the staff. As noted above, the staff did not make a finding about the adequacy of the design on several items for which additional information was not provided.

We pointed out that the source term analyses used in this Chapter depended on the NuScale source term methodology. This methodology was documented in Topical Report, TR-0915-17565, Revision 3, Accident Source Term Methodology, and reviewed by the ACRS in our source term focus area meeting.

Staff Response to ACRS Letter Report The staff response to our initial conclusion indicated that they expected further enhancement of the DCA descriptions in risk-significant areas, consistent with the objectives of the design certification process. As noted above, the staff did not make a finding about the adequacy of the plant in areas where additional design information was not provided.

D. Petti Open Items from Phase 3 Requiring Further ACRS Review There were numerous open items that were closed in Phase 4. I have reviewed how these items were addressed in the staff Phase 4 SER, and I do not recommend further ACRS review.

Recommendation Many of the Chapter 12 issues that we identified in our Phase 3 letter report were addressed by the applicant in subsequent interactions with the staff. In cases where the applicant did not provide additional design information, the staff did not make a finding about the adequacy of the plant and proposed that these items be identified by the Commission in the final rule on the NuScale design. These design features are addressed in our source term focus area review.

As lead reviewer for NuScale DCA Chapter 12, I recommend that the Committee not perform any additional Phase 5 review of this chapter.

D. Petti December 19, 2019

SUBJECT:

PROPOSED RECOMMENDATION FOR ACRS REVIEW OF NUSCALE POWER, LLC, DESIGN CERTIFICATION APPLICATION - SAFETY EVALUATION WITH NO OPEN ITEMS FOR CHAPTER 12, RADIATION PROTECTION Package No.: ML20006G700 Accession No: ML20006G325 Publicly Available Y Sensitive N Viewing Rights: NRC Users or ACRS Only or See Restricted distribution *via email OFFICE ACRS/TSB SUNSI Review ACRS/TSB ACRS NAME MSnodderly MSnodderly LBurkhart DPetti (LBurkhart for)

DATE 12/19/2019 12/19/2019 12/19/2019 12/19/2019 OFFICIAL RECORD COPY