SMART Standard Design Approval inspection result July. 4 th

Transcription

1 SMART Standard Design Approval inspection result July. 4 th

2 Content Ⅰ. Inspection outline. 1 Ⅱ. Inspection proceedings 2 Ⅲ. SMART Standard Design features. 3 Ⅳ. Standard Design inspection result 5 Ⅴ. Comprehensive inspection result.. 12

3 1. Inspection outline SMART outline Applicant: Korea Atomic Research Institute (KAERI)/Korea Electric Power Corporation (KEPCO) Reactor type: integral pressurized water reactor Design life: 60 years Features: integral type, pressurizer and steam generator are installed inside the reactor. Standard Design Approval application: 30 th of Dec Approval standard (section 12 of [Nuclear Safety Act], reactor facility technological standard regulations) Location, structure, facility and performance should meet the technological standards stipulated in the committee regulations. Should meet the standard to prevent harmscaused by radioactive materials on human being in terms of health and environment. SMART Standard Design Approval inspection key points Soundness assessment of reactor vessel s internal structure featuring integral reactor type. Verify the performance and safety of new facilities such as the passive residual heat removal system and review the applicability of safety analysis code. Additionally review follow up measures of Japan s Fukushima nuclear disaster.

4 2. Inspection proceedings After KAERI and KEPCO applied for SMART Standard Design Approval (Dec. 2010), KINS inspected the application documents for around 17 months (Jan ~ May 2012) according to section 111 of the [Nuclear Safety Act] (entrusted right) to check whether they meet the approval standards stipulated in the [Nuclear Safety Act]. SMART Standard Design Approval application (30 th of Dec. 2010) * Application document (section 12 of Nuclear Safety Act): standard design description, standard design safety analysis report, explanation of the purpose of using the reactor, explanation of technological capacity as for the reactor design, emergency operational procedure plan, articles of corporation. Review the appropriateness of submitted document (Jan ~ Feb. 2011) * Supplement 175 submitted documents. SMART Standard Design Approval inspection (Feb ~ May 2012) * Supplement 1,513 data for three times and review questions and answers. Review applying improvements after the Fukushima nuclear disaster (Aug ~ May 2012) * Submit the implementation report draft regarding design improvement since the Fukushima nuclear disaster (31 st of Jan. 2012) and submit final measures (8 th of May 2012). * Review the appropriateness of matters reflected in the follow up measure of Fukushima nuclear disaster.

5 3. SMART Standard Design features [compared with the existing PWR] Integral reactor vessel, excluded large-scale coolant loss accident in the design * Installed steam generator, coolant pump and pressurizer inside the reactor vessel and removed large-scale piping. Removed safety injection tank and simplified the safety injection system. * As large-scale piping is removed, only the refueling water tank can be used as water source of the safety injection system. Adopted once-through helical steam generator * Steam generators (8 units) are designed as helical type and are highly resistant to tube rupture. As it is module type, it can be easily replaced.

6 Passive Residual Heat Removal (PRHR) system. * Passive residual heat removal system replaces the existing supplementary water supply system of the secondary system of light water reactor. * When steam generator is damaged, reactor coolant is only injected into the passive residual heat removal system in the secondary system. Maintenance space determines the size of reactor s containment building [Upper structure storage place] [CSB storage place] [Reactor cover assembly storage place] [Refueling device] [Flow mixing assembly storage place] OPR-1000 SMART Remarks (compared OPR-1000) Caliber 43.8m 36.0m 82.2% Height 81.0m 68.4m 84.4% Volume 89,576m 3 56,390m % Wall thickness 1.2m 1.4m* 117% to *Consider airline collision load.

7 4. SMART Standard Design inspection result A. Standard Design description inspection result Design content as for the structure, system and device of SMART described in the Standard Design description was describedin a way that the design features and performance coincided with the design content in the standard design safety analysis report. SMART s design, construction and performance verification plan suggests appropriate method (inspection, testing, analysis) to check key design features and performance defined in the design content. Permissible standard is appropriately set in line with the design features and functional features of structure, system and device. Design content as for key matters in terms of safety required in the Standard Design description is explained, and the relevant design, construction and performance verification plan is appropriately suggested. B. Explanation of the purpose of using the reactor inspection result SMART reactor has the purpose of producing 330 MWt thermal output and 100 MWe electrical output, and that purpose is appropriate. Confirmed that the reactor applies to the power generating reactor and relevant facilities which can be under Standard Design Approval.

8 C. Explanation of technical capacity as for the reactor design inspection result. KAERI and KEPCO jointly applied for SMART Standard Design Approval. These applicants are assessed to have design and quality assurance capacity securing relevant organization and personnel and also experiences in domestic nuclear power industry. SMART Standard Design Approval applicants turns out to haveappropriate technological capacity as for SMART design securing design technological capacity and quality assurance capacity through personnel, operational system and design and construction experiences. D. Standard design safety analysis report inspection result Site safety - As for the site condition, rock ground and 9 types of soft ground were considered to include domestic sites. Safe shutdown earthquake is set at peak ground acceleration 0.3g, and response spectrum* embraces the standard response spectrum according to NSSC notification** (adapting U.S. Reg. Guide). * 25~50 HZ region of standard response spectrum is conservatively amplified to be used as the design spectrum. ** Notification No of NSSC. (Technological standard as for the location of reactor facilities).

9 Integral reactor system - (Fuel system design) Design standard is set in a way to prevent damage in the fuel system under anticipated operational occurrence (AOO), and the standard is designed as to maintain core cooling capacity without causing damage with the extent that can interfere the insert of reed switch under postulated accident condition. - (Structural soundness) Earthquake-proof analysis and dynamic analysis were conducted on internal structure of reactor vessel, and the result showed that it is designed to maintain structural soundness and functions. Comprehensive vibration evaluation plan including internal structure s vibration/stress and fatigue analysis, vibration measurement, inspection and result analysis turned out to be appropriate. - (Steam generator) Once-through helical steam generator is designed to be separately installed and separated for replacement. Design standard on normal and abnormal conditions such as blowdown load caused by vibration and nozzle damage reflected. - (Applicability of inspection during operational condition) As it is an integral type with complicated internal structure, accessibility for inspection was checked, and the result showed that accessibility on reactor vessel, pressurizer, steam generator, reactor coolant pump and safety grade piping were secured in the designing. - (Overpressure protection) Overpressure protection of reactor coolant system and steam generator is implemented by pressurizer s safety valve and reactor protection system. Result turned out to be appropriate as the pressure is designed to be maintained* within 110% (18.7Mpa) of the design pressure. * Peak pressure of reactor coolant system: normal feedwater 17.27Mpa, feedwater system pipe break 17.43Mpa.

10 - (Reactor vessel) Estimated maximum neutron fluence(1.1x10 14 n/cm 2 ) at the core intine of end of life (60 years) reactor vessel is up till the monitoring test implementation standard (1.0 x n/cm 2 ). * Standard reactor fluence: 6.3 x n/cm 2,40 years of design life. Safe facility in terms of engineering - (Safety of reactor s containment building) As large-scale containment building is adopted which is larger than thermal output, design pressure (35psig) of the containment building secures more than 10% margin compared to the peak pressure (20.33psig) during design basis event. 6 Passive Autocatalytic Recombiner (PAR) is installed to secure hydrogen control capacity. - (Safe injection system) Integral design led to the exclusion of large-scale coolant loss event resulting in simplified safe injection system which consists of physically independent 4 train safety injection pump, pipe and valve. It is designed in a way to respond to coolant loss event even under single failure condition. Therefore, core exposure doesn t occur and it meets long-term cooling standard. - (Passive residual heat removal system) It consists of 4 trains where each train secures 50% volume. It is designed in a way that, using 2 trains, the reactor can be cooled within 36 hours from when the reactor coolant pump is shutdown, until the time when shutdown cooling system starts operation (200 ). Therefore, it meets system s functional requirement.

11 Power conversion system - (Main steam system) Overpressure protection of main steam system is implemented by passive residual heat removal system s pressure relief valve. This system is designed as for the main steam isolation valve to isolate the main steam system within 20 seconds in the case of main steam line break so that safety functions can be carried out. The system meets needed requirements. - (Turbine/power generator and auxiliary system) As for the secondary system including condenser, condensed water and feedwater system, concept design is applied where the size of pump and pipe is not established. Still, it is assessed as having secured safety because the design and functions are the same as existing commercial nuclear operators. Severe event responding design - (Containment building s hydrogen control capacity) 8 passive autocatalytic recombiner (PAR) to deal with severe events are installed to secure hydrogen control capacity in the case of severe event, and hydrogen discharged from the reactor vessel is discharged to reactor drain tank* by reactor depressurization system, preventing the possibility of hydrogen explosion in refueling canal tank inside the containment building and also at the containment building. * Reactor drain tank has an environmental condition of no ignition (maintains 55% or more moisture). - (Reactor joint design) Reactor joint floor area and reactor joint flooding system design assessment result showed that they are appropriately designed; even when no separate measures are taken under the condition that all safety facilities in terms of engineering are not being operated, containment building floor liner does not melt through for around 91 hours (standard 24 hours) after damage occurs in the core.

12 - (Long-term overpressure protection of containment building) Adopted containment building which is larger than thermal output so that even when the spray system doesn t work, overpressure protection of containment building is possible for 72 hours (standard 24 hours) after damage occurs in the core. Restricted area establishment - When postulated accident (coolant loss) occurs at the 300m border of the established restricted area, exposure dose stays within or below the permissive level. Therefore, restricted area establishment is appropriately carried out. * Radiation dose of Thyroid 42.4mSv (permissive level 3,000mSv), radiation dose of total body 10.1mSv (permissive level 250mSv). ** As for the estimated exposure dose at restricted area border during normal operation, the environment of actual construction site needs to be considered, so close review is needed at the construction and operational license inspection stage. Comprehensive site considered in the design includes features of all domestic construction sites, and the standard design of major device and facilities are appropriately designed in terms of output capacity and design life, and safety facilities and severe event responding design is installed to secure core protection capacity in cases of events, proving that it has secured safety. E. Emergency operation procedure plan inspection result. Emergency operation procedure plan was developed based on the emergency operation procedure development plan of existing standard reactor, proving that it is appropriate. Standard measures after reactor shutdown, diagnostic measures during event occurrence, restoration measures for each design basis event and restoration measures in cases of excessive steam release and loss of feedwater safetystated in the emergency operation procedure plan proved to be appropriately stated.

13 F. Fukushima follow up measures inspection result Among 50 measures, 34 SMART items were subject to inspection, and the result showed that improvement measures of 1o items that need to be applied at the standard design stage were appropriately reflected in the standard safety analysis report. - Inspection result showed that 24 improvement items including improvement of alternative emergency diesel power generator design basis and flood prevention measures for ultimate heat sink facilities can all be improved at the construction and operational license stage (after site selection and device purchase). - Items in the U.S. Nuclear Regulatory Commission s safety strengthening measures that were not included in improvement measures after safety inspection of domestic reactors were all included. (Installation of safety grade temperature measuring device at spent fuel storage pool). Confirmed that safety improvement measures at home and abroad established after Japan s Fukushima nuclear disaster are appropriately reflected in SMART standard design. G. Total inspection result SMART Standard Design meets the standard for approval in sub-section 5 of section 12 in the [Nuclear Safety Act]. - Reactor s location (comprehensive site), structure, facilitiesand performance meet the technological standards stipulated in NSSC regulations, and - no harm to human health or environment is expected from radioactive materials occurred by these facilities. As for specific matters which are not subject to standard design approval according to section 24 in the enforcement decree of Nuclear Safety Act such as matters which can be confirmed at purchase, installation and construction stages, their appropriateness should be checked at reactor s construction license and operational license inspection stages by referring to SMART standard design.