ML20197F442
| ML20197F442 | |
| Person / Time | |
|---|---|
| Site: | 05200003 |
| Issue date: | 12/18/1997 |
| From: | Scaletti D NRC (Affiliation Not Assigned) |
| To: | Liparulo N WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP. |
| References | |
| NUDOCS 9712300218 | |
| Download: ML20197F442 (7) | |
Text
.
Decemb:r '18, 1997 Md Nicholas J.' Liparuto, Manager.
Nuclear Safety and Regulatory Analysis Nuclear and Advanced Technology Division Westinghouse Electric Corporation P.O. Box 355 Pittsburgh, PA 15230 SUBJECT : REQUEST FOR ADDITIONAL INFORMATION RELATIVE TO OPEN ITEMS IN THE i
AP600 DESIGN CERTIFICATION REVIEW
Dear Mr. Liparulo:
As a result of the staff's continuing review of the AP600 design certification application, the Plant Systems Branch has prepared the final safety evaluation report (FSER) of Section 9.4, "Alr-Conditioning, Heating, Cooling, and Ventilation System" of the AP600 Standard Safety Analysis Report (SSAR). -The FSER identifies 21 open items needing resolution by.
Westinghouse before the staff can complete its review of this SSAR Esction. The open items are identified in the enclosure.
If you have any questions regarding this request, please contact me at (301) 415-1104,
(
Sincerely, original signed by:
Dino C. Scaletti, Project Manager Standardization Project Directorate Division of Reactor Program Management Office of Nuclear Reactor Regulation
. Docket No.52-003
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Enclosure:
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e Mr. Nicholas J. Liparuto Docket No.52-003 Westinghouse Electric Corporation AP600 cc:
Mr. B. A. McIntyre Mr. Russ Bell j
Advanced Plant Safety & Licensing Senior Project Manager, Programs Westinghouse Electric Corporation Nuclear Energy Institute -
Energy Systems Business Unit 1776 l Street, NW -
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P.O.~ Box 355 Suite 300 i
Pittsburgh, PA 15230 Washington, DC 20006-3706 Ms. Cindy L. Haag Ms. Lynn Connor Advanced Plant Safety & Licensing Doc-Search Associates Westinghouse Electric Corporation Post Office Box 34 Energy Systems Business Unit Cabin John, MD 20818 Box 355 Pittsburgh, PA 15230 Dr. Craig D. Sawyer, Manager Advanced Reactor Programs Mr. Sterling Franks GE Nuclear Energy U.S. Department of Energy 175 Curtner Avenue, MC-754 NE 50 San Jose, CA 95125 19901 Germantown Road Germantown, MD 20874 Mr. Robert H. Buchholz GE Nuclear Energy Mr. Frank A. Ross 175 Curtner Avenue, MC-781 U.S. Department of Energy, NE-42 San Jose, CA 95125 Office of LWR Safety and Technology 19901 Germantown Road Barton Z. Cowan, Esq.
Germantown, MD 20874 Eckert Seamans Cherin & Mellott 600 Grant Street 42nd Floor Mr. Charles Thompson, Nuclear Engineer Pittsburgh, PA 15219 AP600 Certification NE 50 Mr. Ed Rodwell, Manager 19901 Germantown Road PWR Design Certification Germantown, MD 20874 Electric Power Research Institute 3412 Hillview Avenue Mr. Robert Maiers, P.E.
Palo Alto, CA 94303 Pennsylvania Depa:tment of Environmental Protection
- Bureau of Radiation Protection Rachel Carson State Office Buildlag P.O. Box 8469 Harrisburg, PA 17105-8469
-i r e n Air conditionine, Heating, Cooling, and Ventilation System 1Open items 410.415F; The AP600 Standard Safety Analysis Report (SSAR) Sections 9.4.1,9.4.2,.9.4.3,
. 9.4.6,9.4.7,9.4.8,9.4.9,9.4.10, an:19.4.11 represent the heating, ventilating, _
. and air conditioning (HVAC) systems the nuclear island nonradioactive !
ventilation system (VBS), the annex / auxiliary buildings non radioactive HVAC_
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system (VX8), the radiologically controlled area ventilation system (VAS), the
_ containment recirculation cooling system (VCS), the containment air filtration
- system (VF8), the redweste building HVAC system (VRS), the turbine building ventilation system (VTS), the diesel generator building heating and ventilation system (VZ8), and the health physics and hot machine shop HVAC system (VHS)
Each of the identified sections provides a description of applicable instrumentation. However, the location of the instrumentation is not provided. For -
example, the pressure indications and high differential pressure alarms for the system filters and unit coolers are provided; the airflow indication and alarms are :
provided to monitor operation of the supply and exhaust fans; but Westinghouse F
needs to clarify, in each HVAC system write up, where the information is provided.'
is the information provided locally, or in the main control room (MCR), or is it provided in both places?
410.416F:
SSAR figures for the VAS, VBS, VCS, VFS, VXS, and VZS are derived from.
AP600 piping and instrumentation diagrams (P&lDs), However, these figures do not accurately represent the details of the P&lDs, or the PODS and figures are not updated to reflect design changes. Additionally, figures for other HVAC systems such as VHS, VRS, and VTS are not provided, in order for the NRC staff to complete its review of all the HVAC systems, Westinghouse must provide
. updated P&lDs and SSAR figures representing the current design, including major system instrumentation and system interactions, where applicable, such as supply
- s.
of the chilled and hot water being provided from the central chilled water system and the plant hot water system.
- 410.417F:
Westinghouse provided a partial response, without an SSAR update, to the staff's request for additional information (RAl) 410.241 concoming the tabulated flow and pressure data in SSAR Section 9.4 related to the VAS, VBS, VHS, and VRS which maintain their served areas at certain positive or negative pressures with respect to the surrounding spaces and outdoor atmosphere. _ In addition, the VFS should be included in the above HVAC systems list since it maintains the isolated zone of l --
the fuel handling area and auxiliary and annex buildings at a negative pressure
. with respect to the clean areas when high airbome activity or high differential pressure is detected in these areas and VAS exhaust is diverted to the VFS.
Therefore, Westinghouse must provide the flow and pressure data in SSAR Section g.4 for the above HVAC systems. Negative or positive pressure should be in units ofinches water gauge.
-410.418F:
In order to demonstrate compliance with Position C.2 of Regulatory Guide (RG) 1.29, Westinghouse must state in the applicable SSAR sections for each -
HVAC system (VAS, VBS, VCS, VFS, VHS, VRS, VTS, VXS, and VZS) that the W
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L. equipment, ductwork, supports, and accessories are designed and constructed in accordance with the requirements of seismic Category ll, or provide an altemative to preclude them from r ollapsing onto safety-related structures, systems, and components during an safe shutdown earthquake (SSE).
410.419F:
1.
SSAR Section 9.4.1.1.1 states that those portions of the VBS which i
penetrate the MCR envelope are safety-related and tiesigned as seismic l
Category I to provide isolation of the MCR envelope from the surrounding areas and outside environment in the event of a DBA. Therefore, SSAR Figure 9.4.1 1 must be revised to show the piping separation with the required piping and component classifications including safety-related pipe sizes.
2.
SSAR Section 9.4.1.1.2 states that the VBS maintains main control room and technical support center (TSC) areas at a slight positive pressure with respect to the adjacent rooms and outside environment during normal operation to prevent infiltration of unmonitored air into these areas. However, Westinghouse needs to state exactly what negative pressure b required to be maintained in these areas with respect to the outside environment and Ldjacent clean plant areas.
410.420F:
Westinghouse needs to revise SSAR Section 9.4.1.2.2 to state that the isolation dampers are tested in accordance with N510-1989," Testing of Nuclear Alr.
Cleaning Systems, Standards "
410.421F:
Westinghouse needs to revise SSAR Section 9.4.1.2.2 to s' ate that the MCR envelope isolation valves, isolation test valves, and penetration test valves are AGME Section lil-Class 3.
410.422F:
Westinghouse needs to reference the RG 1.140-1979, Revision 1, in SSAR Section 9.4.13 and provide the same reference in all HVAC subsections including 9.4.1 and 9.4.7.
410.423F:
Westinghouse needs to revise SSAR Section 9.4.1.4 under " Abnormal Plant Operation," and state that a representative charcoal sample, used or new, is laboratory tested to verify a minimum charcoal efficiency of 90 percent in accordance with RG 1.140 and conforms to ASME N510-1989 for test procedures and test frequency.
410.424F:
The acceptable location of the single control room outside air intake serving the VBS conforms to the guidance of Section 6.4 of the Standard Review Plan and RG 1.95 and was based on a previous SSAR figure (Figure 1.2-10) showing its location at elevation 153'-0" and previous SSAR Figure 1.2-17 which showed that it was located 35,1 m (115 ft) laterally and 26.2 m (86 ft) vertically below th* plant vent discharge point. However, for the current design Westinghouse needs to verify the location and provide an appropriate figure for the air intake's with appropriate details as indicated here.
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3 410.425F:
As shown in SSAR Figure g.4.1-1 ' the fresh air supply from an air intake is automatically isolatable by a fail-closed, electro-hydraulic operated isolation damper at the inlet of each air filtration train. Normally, ons VBS air filtration unit train isolation damper is opened, and the other air filtration unit train isolation damper is closed. There are two fail-closed isolation dampers in series in the -
common outside silr supply to each of the normal air handling units. The radiation monitors and outside air isolation dampers are shown on Figure g.4.1 1 of the SSAR. The outside air is continuously monitored by redundant smoke monitors at the outside air intake. Redundant safety-related radiation monitors are located in the main control room envelope (MCRE) upstream of the supply air isolation valves. As described in SSAR Section g.4.1.2.3.1, these monitors initiate operation of the non-safety-related supplemental air filtration units on "high" gr.:eous radioactivity concentrations and isolate the MCR from the VBS on "high-high" particulate or iodine radioactivity concentrations. However, SSAR Section g.4.1.2.1.1 Indicates that these monitors initiate operation of the non safety-related supplemental air filtration units on high gaseous radioacJvity concentrations ar.d isolate the MCR from the VBS on high particulate or iodine radioactivity concentrations. Westinghouse needs to clarify the above discrepancy.
410.426F:
la order to be in compliance with the requirements of GDC ig Westinghouse should state in SSAR Section g.4.1 that provisions for redundant toxic gas monitoring is site specific, and that onsite and offsite toxic releases will be evaluated by the COL applicant, as stated in SSAR Section 6.4.7. Additionally, the MCR/TSC HVAC subustem's description must include the subsystem's recirculation mode durin.
.c emergencies, it should describe how subsystem equipment isolates and operates.
410.427F:
In responsa to a question concoming compliance of the VBS with defense in depth criteria, Westinghouse provided a response (OITS No. 28g7) which stated that the system is located in the auxiliary building and equipment will be procured with the appropriate environmental qualification and as with the other equipment of the Nuclear Island, it is protected frr,m defined natural phenomena. However, l
Westinghouse needs to be specific, and provide details describing what requirements of environmental qualification are met when procuring VBS p
equipment for protection against natural phenomena.- Westinghouse needs to state in the SSAR Section g 4.1 that VBS is classified as a defense in depth system.
410.428F: -
The normal outside makeup air is prcvided to the subsystem through an outside air intake duct that is protected by an intake enclosure.' The outside supply air intake enclosure for the MCR/TSC HVAC subsystem is common for the A and C Class 1E electrical room HVAC subsystem air intakes located on the roof of the -
auxiliary building at Elevation 153'-0". However, Westinghouse needs to clarify -
whether this is a seismic Category I enclosure. If it is not, inen provide.
l
. Justification for it not being seismic Category I since the enclosure provides the
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vital function of maintaining the MCR envelope at a s!!ght (provide specific data)
L positive pressure during normal operations and at least.03kPa (1/8 inch water
~ gauge) positive pressure when a high gaseous radioactivity concentration is detected in the MCR supply air duct.
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410.42gF:
Each supplemental air filtration unit includes a high efficiency filter bank, an electric heating coil, charcoal adsorber with upstream high-efficiency particulate air (HEPA) filter bank and a downstream bank, and a fan. Both redundant trains L of supplemental filtration units and the one train of supply air handling unit (AHU) -
- are located in the MCR mechanical equipment room at Elevation 135' 3" of the auxiliary building. The other supply AHU is located in the MCR mechanical equipment room at Elevation 135' 3" of the annex building. The MCR toilet exhaust fan is located at Elevation 135'1" of the auxdiary building. However, Westingnouse needs to clarify whether the filtration unit's housings are located outside the MCRE and designed for positive pressure (provide specific pressure data).-
410.430F:
To verify the Westinghouse assertion, the staff pedormed independent
- radiological consequence calculations for personnel in the main control room and technical support center following a design basis LOCA. The staff finds that the system design as bounded by the control room atmospheric relative concentrations proposed by Westinghouse is capable o controlling radioactivity r
following a design basis LOCA to meet the dose criteria specified in GDC ig of
- Appendix A to 10 CFR Part 50 (as applied to the AP600 design: 5 rem total-effective dose equivalent (TEDE)). However, the system is not designed as a post accident engineered safety feature atmospheric cleanup system. The VBS has no safety grade source of power; therefore, it was not credited in evaluating conformance with GDC ig. The major assumptions used by the staff and the resulting radiological consequence analyses are provided in Table 15.10 of this report.
410.431F:
During abnormal operation, when high gaseous radioactivity (HIGH) is detected in the MCR supply air duct and the MCR/TSC HVAC subsystem is operable, both supplemental air filtration units automatically starts to pressurize the MCR/TSC areas to at least 0.03 kPa (1/8 in water gauge) using filtered makeup. One of the supplemental filtration units is manually shutdown, the normal outside air makeup duct and the MCR and TSC toilet exhaust duct isolation valves close; and the smokelpurge isolation dampers close,if open. The subsystem AHU continues to provide coe:ing in the recirculation mode by maintaltsing the MCRE passive heat sink below its initial ambient air design temperature and maintaining the MCR/TSC areas within their design temperature. The supplemental filtration pressurizes the combined volume of the MCR and TSC concurrently with filtered air. A portion of the rocirculated air from the MCR and TSC is also filtered for
- cleanup of airbome radioactivity. However, Westinghouse needs to provide the following:
1, State that the positive pressurization of 0.03 kPa (1/8 in. water gauge) is
- "with respect to the adjacent rooms and outside environment" and revise the SSAR Section g.4.1.2.3.1 accordingly.-
2.
The portion (percentage) of the recirculated air from the MCR and TSC that is filtered for cleanup of airbome radioactivity.
- 410.432F:
During abnormal operation, if ac power is unavailable for more than a short period or "high-high" particulate or lodine radioactivity is detected in the MCR supply air
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t 5-duct, which would lead to exceeding GDC ig operator dose limits, the plant safety monitoting system automatically isolates the MCR envelope from the normal MCR/TSC HVAC subsystem by closing the supply, retum, and toilet exhaust isolation valves. The VES safety-related supply isolation valves in each train opens automatically to protect the MCR occupants from a potential radiation release, because the radiation monitors are effective only when there is air flow through the VBS ductwork. Section 6.4 of this report discusses the emergency mode of operatior. However, Westinghouse needs to state exactly what is *a short period" when power is unavailable during abnormal operation.
- 410.433F:
During abnormal operation, if ac power is unavailable for more than a short period or "high-high" particulate or lodine radioactivity is detected in the MCR supply air duct, which would lead to exceeding GDC ig operator dose limits, the plant safety monitoring system automatically isolates the MCR envelope from the normal MCR/TSC HVAC subsystem by closing the supply, retum, and toilet exhaust isolation valves. The VES safety related supply isolation valves in each train opens automatically to protect the MCR occupants from a potential radiation release, because the radiation monitors are effective only when there is air flew through the VBS ductwork. Section 6.4 of this report discusses the emergency mode of operation. However, Westinghouse needs to state exactly what is "a short period" when power is unavailable during abnormal operation.
410.434F:
When complete ac power is lost and the outside air is acceptable based on compliance with GDC ig requirements conceming the MCR operator doses and toxic releases, MCR envelope habitability is maintained by operating one of the two MCR ancillary fans to supply outside air to ihe MCR envelope. The outside air supply pathways to the ancillary fans and warm air vent pathways are described in SSAR Section g.4.1.2.3.1. Power to the ancillary fans is from the respective division B or C regulating transformers which receive power from the ancillary diesel generators. The ancillary fans flow paths are located within the auxiliary building which is a seismic Category I structure. Once the normal ventilation is restered, the ancillary fan circuits are disabled manually.
Westinghour,e states that the ancillary fan capacity and air flow rate maintain the MCR envelope environment near the daily average outdoor air temperature.
However, Westinghouse needs to provide ancillary fan capacity and flow rate data for the staff's review.
410.435F:
During normal operation, one of the redundant supply AHus, retum fans, and battery room exhaust fans operate continuously to maintain acceptable environmental conditions, maintain the Class 1E electrical room emergency passive heat sink below its initial ambient air temperature, and prevent a hydrogen gas buildup in the Class 1E battery roms. The battery exhaust is vented directly to the turbine building vent to limit the hydrogen gas concentration to less than 2 percent by volume in accordance with RG 1.128, Revision 1, " Installation Design and installation of Large Lead Storage Batteries for Nuclear Power Plants."
However, Westinghouse needs to reference the RG 1.128, Revision 1, in SSAR Sections g.4.1 and 9.4.13.
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