ML18298A112

LLC Supplemental Response to NRC Request for Additional Information No. 489 (Erai No. 9534) on the NuScale Design Certification Application

ML18298A112
Person / Time
Site:	NuScale
Issue date:	10/25/2018
From:	Wike J NuScale
To:	Document Control Desk, Office of New Reactors
References
RAIO-1018-62242
Download: ML18298A112 (6)

Text

RAIO-1018-62242 October 25, 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 Supplemental Response to NRC Request for Additional Information No. 489 (eRAI No. 9534) on the NuScale Design Certification Application

REFERENCES:

1. U.S. Nuclear Regulatory Commission, "Request for Additional Information No. 489 (eRAI No. 9534)," dated June 15, 2018

2. NuScale Power, LLC Response to NRC "Request for Additional Information No. 489 (eRAI No.9534)," dated August 30, 2018 The purpose of this letter is to provide the NuScale Power, LLC (NuScale) supplemental response to the referenced NRC Request for Additional Information (RAI).

The Enclosure to this letter contains NuScale's supplemental response to the following RAI Question from NRC eRAI No. 9534:

• 06.04-5 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 Carrie Fosaaen at 541-452-7126 or at cfosaaen@nuscalepower.com.

JenJtta~

Sincerely, Manager, Licensing NuScale Power, LLC Distribution: Gregory Cranston, NRC, OWFN-8G9A Omid Tabatabai, NRC, OWFN-8G9A Samuel Lee, NRC, OWFN-8G9A Enclosure 1: NuScale Supplemental Response to NRC Request for Additional Information eRAI No. 9534 NuScale Power, LLC 1100 NE Circle Blvd. , Suite 200 Corvalis, Oregon 97330 , Office: 541.360.0500 , Fax: 541.207.3928 www.nuscalepower.com

RAIO-1018-62242 :

NuScale Supplemental Response to NRC Request for Additional Information eRAI No. 9534 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.: 9534 Date of RAI Issue: 06/15/2018 NRC Question No.: 06.04-5 Regulatory Basis:

10 CFR 52.47(a)(2) requires that a standard design certification application include an 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 that a control room be provided with adequate radiation protection to permit access and occupancy of the control room under accident conditions without the personnel receiving radiation exposures in excess of 0.05 Sv (5 rem)

TEDE for the duration of the accident.

10 CFR Part 20 Subpart C Occupational Dose Limits, states in part that the licensee shall control the occupational dose to individual adults, except for planned special exposures under § 20.1206, to the following dose limits. (1) An annual limit, which is the more limiting of:

The total effective dose equivalent being equal to 5 rems (0.05 Sv); or The sum of the deep-dose equivalent and the committed dose equivalent to any individual organ or tissue other than the lens of the eye being equal to 50 rems (0.5 Sv).

10 CFR Part 20 Subpart C Occupational Dose Limits, requires consideration dose resulting from external radiation sources and dose due to the inhalation of radionuclides.

10 CFR Part 20 Subpart H Respiratory Protection and Controls to Restrict Internal Exposure in Restricted Areas, states that if the licensee assigns or permits the use of respiratory protection equipment to limit the intake of radioactive material, that the licensee will implement a respiratory protection program that includes the following elements:

NuScale Nonproprietary

Supervision and training of respirator users; Fit testing; Determination by a physician that the individual user is medically fit to use respiratory protection equipment:

o Before the initial fitting of a face sealing respirator; o Either every 12 months thereafter, or periodically at a frequency determined by a physician.

Question :

In response to RAI 9079, question (e), the applicant states that as added protection against radiation overexposure, if the area radiation monitor radiation level exceeds a limit (to be set by the licensee), the operators would trip any operating reactors, initiate decay heat removal and containment isolation, and vacate the control room. In their application, NuScale has also identified that the presence of toxic gas may result in a condition where the Main Control Room (MCR) operators may need to vacate the MCR.

In implementing its statutory authority under the Atomic Energy Act, the NRC preempts the application of the Occupational Safety and Health Act for working conditions that involve radioactive materials. That is, the training, medical, fit test, etc. requirements are provided by the NRC in 10 CFR Part 20 Subpart H. However, a Memorandum of Understanding (MOU) between the Occupational Safety and Health Administration and the NRC, states that if an NRC licensee is using respiratory protection to protect workers against non-radiological hazards (i.e.,

toxic gas), the OSHA requirements apply.

Since the action of the operators to leave the confines of the MCR would potentially expose the operators to concentrations of radiological contaminants or toxic gases, that could result in the operators exceeding the regulatory limits in the short time required to reach the alternate safe location for the MCR operators, the MCR operators need to be able to wear the appropriate respiratory protection device. The applicant has identified in COL item 6.4-1 that the COL applicant has the responsibility to ensure that the MCR operators are able to use respiratory protection equipment, which should include consideration of radiological contaminants as well as toxic gases. The NuScale FSAR does not state that respiratory protection equipment (e.g.,

self-contained breathing apparatus (SCBA)) would be staged in the control room as a backup if the control room becomes uninhabitable. COL item 6.4-1 tells the COL applicant to comply with RG 1.78, Evaluating the Habitability of a Nuclear Power Plant Control Room During a Postulated Hazardous Chemical Release, to evaluate control room habitability for hazardous chemical releases. RG 1.78 discusses use of respiratory protection equipment for hazardous NuScale Nonproprietary

chemical releases, but does not explicitly discuss respiratory protection for radiological releases.

Therefore, the staff requires the following information in order to complete its review:

Provide a COL Item requiring the applicant to provide a storage location for SCBAs that allows the MCR operators to access, don, place the facility in a safe condition and move to a safe location without exceeding the radiation exposure limits of 10 CFR Part 20, and the exposure to toxic substance guidance in RG 1.78, in the event that both MCR ventilation systems do not function. Or provide reasoning (1) why an alternative method would be acceptable, or (2) why SCBA would not be needed.

NuScale Response:

Background:

NuScale agreed to submit a supplemental response during a meeting on October 3rd, 2018 to discuss RAI 6.4-5, specifically the description of the role of the COL emergency response organization with respect to radiation protection equipment for control room operators. The original RAI response has been superseded to reflect discussed clarifications as shown below.

Supplemental Response:

The simultaneous failure of the normal control room HVAC system (CRVS) and the control room habitability system (CRHS) coincident with a design basis event is not considered credible.

After 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> of CRHS operation, the normal control room ventilation system would be available for use, except after a seismic event. After a seismic event the normal control room ventilation system may not be available for use but dose consequences are not applicable because mitigating SSCs are Seismic Category I and capable of performing their safety-related and nonsafety-related functions during and following the event. Therefore a COL Item requiring a storage location for SCBA in the event that both MCR ventilation systems do not function is not needed.

In addition, as described in the response to RAI 9079 (NuScale letter RAIO-1017-56676 dated October 18, 2017, ML17291A672 ), the design specifications for the Main Control Room Ventilation systems and accompanying COL Items e.g., 6.4-1, 6.4-5 and 9.4-1, provide a high degree of system reliability as well as chemical and radiation protection for control room personnel under accident conditions. A significant beyond design basis event would be required to defeat the current design.

NuScale Nonproprietary

Impact on DCA:

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

NuScale Nonproprietary