ML20154H918

Summary of ACRS Advanced Reactors Subcommittee 860130 Meeting W/Nrc,Doe,Ga Co,Gas Cooled Reactor Assoc,Ieal,S&W, ORNL,C-E & Bechtel in Washington,Dc to Review DOE HTGR Design

ML20154H918
Person / Time
Issue date:	02/12/1986
From:	Advisory Committee on Reactor Safeguards
To:	Advisory Committee on Reactor Safeguards
References
ACRS-2394, NUDOCS 8603100404
Download: ML20154H918 (6)

Text

[)d R 6 - 23 9(/

s PDA0303GG fIW Tg DATE ISSUED: 2/12/86 2/a/e.

PR0 POSED MINUTES /

SUMMARY

OF THE ACRS ADVANCED REACTORS SUBCOMMITTEE MEETING JANUARY 30, 1986 WASHINGTON, DC Purpose The purpose of the meeting was to review the HTGR design that was submitted to the NRC Staff by DOE and to detennine the bases for select-ing the design basis events.

Meeting Attendees:

ACRS NRC Staff M. W. Carbon, Chairman T. King J. C. Mark, Member P. Williams C. P. Siess, Member M. El-Zeftawy, Staff Others F. Silady, GA DOE A. Kelley, Jr., GCRA A. Millunzi A. Neylan, GA G. Sherwood J. Fuoto, IEAL A. Mehner L. Walker, SWEC R. Ng W. Sheridan, SWEC P. Kasten, ORNL S. Caspersson, CE fgj31ggg4060212 T. Henry, CE 23n m A. Sweency, Bechtel Highlights, Agreements, and Requests

1. T. King, Safety Program Evaluation Branch /NRR, overviewed the status of NRR's interactions with DOE on the advanced HTGR program.

The overall review plan consists of:

C 'IC'iE: J 0,w; g,gr,

.Catstgya 3,,

Advanced Reactors Meeting January 30, 1986

a. Review conceptual design and key issues over the next cwo years. This includes:

• Agree on Criteria

• Assess Potential of the design for satisfying these criteria

• Assess R&D programs supporting the design

• Issue SER and licensability statement

b. Identify additional steps NRC must take to be ready to process an HTGR application.

2. Messrs. A. Millunzi (00E), A. Kelley, Jr. (GCPA), W. Sheridan (SWEC),A.Neylan(GA),andF.Silady(GA)presentedtheHTGR concept for wide range of applications in support of Consnercial/

User interests in safety and higher temperature characteristics of these plants.

3. DOE developed the HTGR plant design ut.ing a systems engineering methodology called the " Integrated Approach". One element of the Integrated Approach is the functional analysis, a technique used to derive the relationships between functions which a plant performs and related requirements and to develop the bases and justification for design selections supporting an overall objective.

4. DOE developed a plan of interactions with the NRC Staff regarding the HTGR's design and licensability. The plan consists of four areas: a procedural approach, a technical approach, a de-sign / technology familiarization, and a design / technology review.

The procedural approach was submitted and has been completed.

d Advanced Reactors Meeting January 30, 1986

5. The technical approach interaction includes the submittal of top-level criteria. The top-level criteria are defined as the standards for judging licensability that directly specify accept-able limits for protection of the public health and safety. The top-level criteria combined with the Integrated Approach methodolo-gy were used to derive the lower-level design requirements.

6. The Integrated approach will be used to provide a systematic orderf.ng of the functions and requirements necessary to achieve four comprehensive goals which are:

• Maintain safe plant operation

• Maintain plant protection

• Maintain control of radionuclide release

• Maintain emergency preparedness

7. The sources used for development of the top-level regulatory criteria are:

• NUREG-0880 - Safety Goals for Nuclear Power Plant operation.

• 10 CFR 20 - Permissible dose levels and activity concen-trations in unrestricted areas.

• 10 CFR 50, Appendix I - Numerical dose guidelines for meeting the criterion, "As Low As Is Reasonably Achievable," for power reactor effluents.

'i

Advanced Reactors Meeting January 30, 1986

• 10 CFR 100 - Numerical dose guidelines for detemining the exclusion area boundary, low population zone, and population center distance.

• EPA-520/1-75-001 - Protection Action Guide Doses for Protec- ,

tive Actions for Nuclear Incidents.

8. DOE started out with over 16 HTGR design concepts and after careful evaluation of the economic and technical feasibility through interactions with the NRC staff, it decided on one smaller sized HTGR design concept.

9. In March 1985, the side-by-side steel vessel concept was selected as the reference oesign to be further developed. The concept was studied with two types of fuel, pebble bed and prismatic. In August 1985, the concept using prismatic fuel was selected for further development in FY 1986. The fuel (LEU /Th-Uranium TRISO coated particles) is arranged in an annular pattern with control rods located in both the central and side reflector regicns.

The prismatic fuel option uses four modular, steel vessel reactors in the side-by-side configuration, each operating at a power level of 350 h t and supplying steam to two turbine generators. The net plant electrical output is 558 N e.

10. The reactor is housed in an uninsulated steel vessel about the size of a BWR reactor vessel. The reactor vessel is contained in an underground concrete silo or cavity which is designed as a heat removal system of last resort. The nuclear island portion consists of four reactor enclosures and adjacent structures that house fuel handling, helium processing, and other essential reactor service systems. A common control room is used to operate all four reac-tors and the turbine plant.

4 Advanced Reactors Meeting January 30, 1986

11. Normal decay heat removal is accomplished by forced circulation of helium and removal of heat through the steam generator or through a small auxiliary system cooler. Passive means are provided as a backup.

12. The design has no containment. A confinement system is used in the design.

13. DOE claims that radiation releases, including the release that could come from a core heatup during the passive decay heat rejection mode, result in public doses that are well below statutory limits. In addition, doses will be below the EPA Protective Action Guidelines (PAG) dose of less than 1 rem whole body and 5 rem thyroid, indicating that a public evacuation plan should not be required.

14. The portion of the plant that the NRC staff is planning to review at the conceptual design stage is the nuclear island. This will include all safety related systems. The review of other plant systems (turbine, steam /feedwater system, etc.) will be mainly of the functions and interface requirements associated with these. It is a goal of this concept to concentrate all safety related functions into the nuclear island and thus have the option in the balance of plant (BOP) to build to different standards.

Future Actions Dr. Carbon will brief the full ACRS in February 1986 regarding the HTGR design. DOE and the NRC staff will be prepared to give a complete presentation at the March 1986 full ACRS meeting regarding both the HTGR and LMRs designs.

i .

Advanced Reactors Meeting January 30, 1986 NOTE: Additional meeting details can be obtained from a transcript of this meeting available in the NRC Public Document Room, 1717 H Street, NW, Washington, DC, or can be purchased from ACE-Federal Reporters, 444 North Capitol Street, Washington, DC 20001 (202) 347-3700, t

i r

s

_ _ _ ,