ML20062K575

Responds to 931126 Request for Addl Info Re Simplified BWR Design

ML20062K575
Person / Time
Site:	05200004
Issue date:	12/13/1993
From:	Leatherman J GENERAL ELECTRIC CO.
To:	Borchardt R NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation
References
MFN-226-93, NUDOCS 9312230003
Download: ML20062K575 (5)

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- GENuclear Energy Geresmeme Comany 11b Curtner Avenue. kn h e, CA 35125 December 13,1993 MFN No. 226-93 Docket STN 52-004 Document Control Desk U.S. Nuclear Regulatory Commission Washington DC 20555 Attention: Richard Borchardt, Director Standardization Project Directorate

Subject:

Transmittal of Responses to NRC Questions

References:

1. MFN No.199-93, Docket STN 52-004

2. Letter, M. Malloy to P. W. Marriott," Request for Additional Information (RAI) Regarding the Simplified Boiling Water Reactor (SBWR) Design", November 26,1993 GE's responses to the questions and comments received from the Staff during the October 6, 1993, telecon were transmitted in Reference 1. Subsequent to that transmittal, Reference 2, containing different phrasing of some questions previously responded to and some questions not previously responded to, was received. The purpose of this letter is to respond to the Reference 2 letter. Attachment 1 to this letter: (a) reiterates previously transmitted responses within the Staff's numbering system for convenient identification and (b) provides responses to questions not previously answered.

Sincerely, L < >

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J. E. Leatherman SBWR Certification Manager MC-781, (408)925-2023 cc: M. Malloy, Project Manager (NRC) (2 attachments)  !

Fat Eng (NRC) (1 attachment) l Gregg Galletti (NRC) (1 attachment)  ;

R. Hasselberg, Project Manager (NRC) (1 attachment) l 21005.; -

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Attachment 1 to MFN No. 226-93 i 620.1 Questions: During a conference call between Nuclear Regulatory Commission and GE Nuclear Energy (GE) staffs on October 6,1993, GE indicated that it ,

intended to submit complete revisions of Section 13.2, " Training", Section 13.5,  ;

" Plant Procedures" and Chapter 18, " Human Factors Engineering", of the  :

SBWR Standard Safety Analysis Report (SSAR by the first week of November,  ;

193. The revised submittal is expected to be very similar to the information provided in Amendment 32 of the Advanced Boiling Water Reactor (ABWR) i SSAR. Provide the SSAR revisions and include in the submittal the additional e information (detailed in Ouestions 620.2 through 620.9, below) as agreed  ;

during the call.

Response: Preparation of the subject SSAR section revisions is being finalized - l and they will be transmitted in the near future. Responses to Questions 620.2 through 620.9 are listed below.

620.2 Question: In SECY-91-272," Role of Personnel and Advanced Control Rooms  !

in Future Nuclear Power Plants", dated August 27,1991, the staff stated that it  !

believed that the role of the operator in the passive plant control rooms would  ;

he significantly different than that of operators in evolutionary plants.

Specifically, operators will use non-safety-related control systems before safety .

systems in responding to a plant event. Based on the differences in approach i to system usage, the staff believes that a fully integrated control room prototype will be needed. Please explain, in detail, why no prototype is  :

proposed for the SBWR design. t Response: The NRC position taken in SECY 91-272 is that the role of the operator in the passive plant control room will be significantly different than  :

that the role proposed for the operator in evolutionary plants. This position is  :

based upon the tenets that (1) in the passive plants,- the operators will use non-safety-related control systems and " investment protection" systems before safety systems in responding to an event, (2) the safety systems in the passive plants are significantly different from current or evolutionary plant safety ,

systems, (3) passive plants have increased automation compared to ,

evolutionary plants and (4) passive plants have greater use of advanced ,

technology than evolutionary plants.  ;

GE believes that the roles of the plant operators in the 73V/R and ABWR are essentially identical. In each type of plant, the operators will be required to monitor and control plant process parameters using non-safety-related and ,

safety-related systems to respond to transients and accidents. Each of the points raised by the Staff above will be considered below.

(1) Certain non-safety and investment protection systems are used in both .

, conventional BWRs and the ABWR before safety systems in responding to an event. For example, the Reactor Water Cleanup, Reactor Building HVAC, i Condensate Makeup Water and non-safety portions of the Residual Heat Removal systems are used during the mitigation of different events in these plants. The use of these systems in SBWR is comparable to conventional -

BWRs and the ABWR. >

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l (2) The passive safety systems in the SBWR are different from the safety >

systems in ABWR and conventional plants in that the passive systems are ,

inherently more reliable due to their utilization of natural physical principles.

Ilowever, the passive systems are automatically initiated under certain ,

conditions and can be manually initiated under other conditions just as do the ~i conventional safety systems. The difference between the passive safety systems  :

and the conventional safety systems is largely invisible to the operator. ,

Furthermore, the symptomatic emergency procedure guidelines (Appendix  ;

18A) do not make any distinction in the use of safety-related vs.

non-safety-related systems, as is the case for any BWR. The operators will be I trained and instructed in the use of these proceduresjust as in presently operating BWRs. The 72-hour no operator action is a design capability, only, ,

and does not imply that the operators will take no actions for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> after initiation of an accident event. To the contray, operators will follow the ,

SBWR EOPs as soon as EOP entry conditions occur.  :

(3) The degrees of automation of plant operations in the ABWR and SBWR are essentially identical. ,

(4) The SBWR does not have any advance technology which is not used in the ABWR.

4 620.3 Question: GE stated during the conference call on October 6,1993, that it -

intended to incorporate the standard features used for the ABWR design on -

the SBWR. Justify, in detail, why the use of each standard feature previously identified for an evolutionary plant is acceptable for a passive plant, given the .

staff's position as stated in SECY-91-272. '!

Response: The standard features of the evolutionag plant main control room were developed to meet the human-system interface (HSI) design bases j described in Section 18.2 of the ABWR SSAR. The design bases for the SBWR main control room HSI (Section 18.2 of the SBWR SSAR) are identical ,

to those for the ABWR. Therefore, it is appropriate to utilize the same  ;

standard HSI features. Also, refer to the response to Question 620.2. t i

620.4 Question: If computerized procedures will be implemented as part of the  ;

SFWR control room design, provide as part of the SSAR, a section which includes the technical basis for selection of computerized procedures, as well as a detailed description of the planned development and verification and i validation procedures required to develop these procedures and the digital  :

interface.

Resp <mse: Computerized EOPs are not discussed in the SSAR. In general, i the subjects of procedures and training are handled similarly in the SBWR SSAR as for ABWR. The inclusion of computerized EOPs in the final HSI .

desi;n t is an issue which will be dealt with by each COL applicant.

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, i Attachment 1 to MFN No. 226-93 620.5 Question: Explain the differences in operating philosophy between active plant design which utilizes active components, such as, pumps, to mitigate an accident and a passive plant design which utilizes natural forces to mitigate an accident. Discuss how these differences will affect operator cognitive tasks and design of the human-system interfaces.

Response: GE's intent is that there be no significant difference in the operating philosophy between the ABWR and the SBWR. In both designs, the  !

high degree of automation provides for enhanced operability and improved  !

capacity factor, relative to conventional BWR designs. However, the extent of automation implemented in both the ABWR and SBWR has been carefully selected to ensure that the primary control of plant operations remains with ,

the control room operators. GE agrees with EPRI that the difference in the roles of the operators in the two plants is limited to the details and timing of the actions taken by them.  ;

620.6 Question: Provide the task analysis used to derive the minimtun inventory of controls, displays and alarms contained in SSAR Appendix 18F.

i Response: The task analysis performed to support the development of the  ;

SSAR minimum inventory consisted of completing the same fourteen point analysis agreed upon between the Staff and GE and performed to support the development of the ABWR minimum inventorylist. He results of the SBWR task analysis are available in San Jose for review.

620.7 Question: Three critical operator actions are identified in the Emergency Procedures Guidelines (EPGs). Please provide specific references to the EPG steps covering the Probabilistic Risk Assessment (PRA)-based actions, a i discussion of how the actions were identified and state whether the PRA included an analysis of Level 1,2 and 3 events. '

Response: No critical operator action were identified in the SBWR PRA. The  :

SSAR discussion (Section 18F.1) of critical operator actions identified in the 3 PRA is being updated in the revised Chapter 18 the DRAFT of which will be .l fonvarded shortly. .

620.8 Question: GE has stated that the minimum set of controls, displays and alarms described in SSAR Appendix 18F includes visual display unit (VDU) and ,

divisional VDU-based items. Is it GE's intent to include only those items '

designated as " fixed-position" in the SBWR Tier 1 Design Document; i.e., in .,

the inspections, tests, analyses and acceptance criteria (ITAAC); or will the j entire minimum inventory be included in the ITAAC?  !

Response: The controls, displays and alarms listed in the SBWR Tier 1 Design i Document will include only those designated as " fixed-position" in SBWR SSAR Appendix 18F. This follows the convention agreed upon between the j NRC and GE for the ABWR Tier 1 Design Document. l i

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I 620.9 Question: Identify the technical contact for the SBWR EPGs and indicate i whether the EPGs are based on Revision 4 of the BWR Owners Group ,

Guidelines.  ;

t Response: The current technical lead for the SBWR EPGs is Cal Tang. Yes,  ;

the SBWR EPGs are based upon Rev. 4 of the BWR Owners Group  !

Guidelines. l 620.10 Question: Discuss what control barriers there will be between passive safety feature actuation and operator intervention.

i Resp <mse: Design details such as control barriers are not described in the .

SSAR. This issue of what type of barrier to implement on controls for passive safety systems will be dealt with during the detailed human-system interface  ;

(HSI) design implementation process described in Appendix 18E of the SSAR. ,

62.0.11 Question: Describe the provisions for control room habitability during the i 72-hour period immediately following a design-basis accident. ,

Response: The topic of control room habitability is discussed in SSAR Section r 6.4 and the radiation exposure aspect of control room habitability is discussed ,

in the SSAR Subsection 15.6.5. For more information on this topic please i contact Earl Nichols (408-925-4288). t i

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