enertech support capabilities for fukushima response

8/2/2019 Enertech support capabilities for Fukushima response

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Enertech supportcapabilities forFukushima response

Enertech business unit of CWFC

Deane C. Beck


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Fukushima response

References:

1. USNRC Generic Letter 89-16, September 1, 1989Installation of Hardened Wetwell Vent

2. Boston Edison Letter to USNRC doc. 88-125,

August 18, 1988 Safety Enhancement Program

3. USNRC Near Term Task Force July 12, 2011Recommendations for Enhancing Reactor Safety in the21st Century

USNRC Notifications


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Fukushima response

A hard pipe vent and vent valves capable of withstandingthe anticipated severe accident pressure loadings would

eliminate the problems with operating the vent systemduring a severe accident. The vent isolation valves shouldbe remotely operable from the control room and shouldbe provided with a power supply independent of normal

or emergency AC power. Other changes, such as raisingthe RCIC turbine back-pressure setpoint, may also bedesirable and could be considered. Venting capability, inconjunction with proper operating procedures and other

improvements discussed in this item, would greatlyreduce the probability of core-melt due to station blackoutsequences.

USNRC Generic Safety Issue 157 and Generic Letter 89-16


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Fukushima response

GE BWR containment evolution


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GE BWR Mark I Containment


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GE BWR Mark I Hardened Containment Vent


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Fukushima response

GE BWR Mark I Containment combustible gas control


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GE BWR Mark II Containment


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Fukushima response

GE BWR Mark II Containment combustible gas control


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GE BWR Mark III Containment combustible gas control


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Fukushima response

USNRC accepted Hardened Wet well Vent modification (Pilgrim)


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USNRC accepted Hardened Wetwell Vent modification (Pilgrim)


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US BWR Mark I upgrades with dates


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Fukushima response

Other modifications made to BWR Mark I Containments include:

Quenchers were installed to distribute the steam bubbles in order toproduce rapid condensation and to reduce loads on the unit. In a reactor,exhaust steam is piped into a suppression chamber, which is known as thetorus and is a large, rounded suppression pool that sits next to the reactorcore. It is used to remove heat when large quantities of steam are releasedfrom the reactor. In the torus, the steam bubbles go under water. With themodification to the Mark I, the quenchers, which are also underwater, make

steam bubbles smaller by breaking up the larger bubbles. This in turnreduces pressure.

Another modification is the installation of deflectors inside the torus. Whenthat steam goes in, the water level rises. The deflectors that were addedbreak up the pressure wave that is produced and help relieve pressure on

the torus.

A further modification was made to the saddles on which the torus sits basically the series of leg-like structures that support it. The construction wasfortified, as was the steel, to accommodate the loads that are generated.

US BWR Mark I upgrades (other)


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Fukushima response

The current condition of the Unit 1, 2, and 3 reactors isrelatively static, but those units have yet to achieve a

stable, cold shutdown condition. Units 1, 2, 3, and 4 alsoexperienced explosions further damaging the facilitiesand primary and secondary containment structures. TheUnit 1, 2, and 3 explosions were caused by the buildup of

hydrogen gas within primary containment producedduring fuel damage in the reactor and subsequentmovement of that hydrogen gas from the drywell into thesecondary containment. The source of the explosivegases causing the Unit 4 explosion remains unclear. Inaddition, the operators were unable to monitor thecondition of and restore normal cooling flow to the Unit 1,2, 3, and 4 spent fuel pools.

USNRC Near Term Task Force Report summary July 12, 2011


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Fukushima response

The 8-hour coping strategy should also ensure that containmentintegrity can be established if needed, including the capability tooperate wetwell vents for BWR facilities with Mark I and Mark II

containments, and one train of hydrogen igniters at BWR facilitieswith Mark III containments and at PWR facilities with ice condensercontainments.

In BWRs with a Mark II containment design, the containment volume

could be approximately 25 percent larger than the volume of Mark Icontainments. In the resolution of GSI157, ContainmentPerformance, the staff concluded that that the need for hardenedvents at BWRs with Mark II containments should be evaluated on aplant-specific basis through the IPE program. Eight BWR units in the

United States have Mark II containment designs. Three of these unitshave installed hardened vents, and the remaining five units at threesites have not installed hardened vents.

USNRC Near Term Task Force observations July 12, 2011


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USNRC Near Term Task Force observations July 12, 2011


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Recommendation 5

The Task Force recommends requiring reliable hardened vent designsin BWR facilities with Mark I and Mark II containments.

The Task Force recommends that the Commission directthe staff to take the following actions to ensure theeffectiveness of hardened vents:

5.1 Order licensees to include a reliable hardened vent inBWR Mark I and Mark II containments.

This order should include performance objectives for the

design of hardened vents to ensure reliable operation andease of use (both opening and closing) during aprolonged SBO

USNRC Near Term Task Force recommendations July 12, 2011


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Fukushima response

Recommendation 7

The Task Force recommends enhancing spent fuel pool makeup capability andinstrumentation for the spent fuel pool.

The Task Force recommends that the Commission direct the staff to do the following:

7.1 Order licensees to provide sufficient safety-related instrumentation, able towithstand design-basis natural phenomena, to monitor key spent fuel pool parameters(i.e., water level, temperature, and area radiation levels) from the control room.

7.2 Order licensees to provide safety-related ac electrical power for the spent fuel poolmakeup system.

7.3 Order licensees to revise their technical specifications to address requirements tohave one train of onsite emergency electrical power operable for spent fuel poolmakeup and spent fuel pool instrumentation when there is irradiated fuel in the spent

fuel pool, regardless of the operational mode of the reactor. 7.4 Order licensees to have an installed seismically qualified means to spray water into

the spent fuel pools, including an easily accessible connection to supply the water(e.g., using a portable pump or pumper truck) at grade outside the building.

7.5 Initiate rulemaking or licensing activities or both to require the actions related to the

spent fuel pool described in detailed recommendations 7.17.4.

USNRC Near Term Task Force recommendations July 12, 2011


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Initiate rulemaking to revise 10 CFR 50.63 to requireeach operating and new reactor licensee to (1) establish

a minimum coping time of 8 hours for a loss of all acpower, (2) establish the equipment, procedures, andtraining necessary to implement an extended loss of allac coping time of 72 hours for core and spent fuel poolcooling and for reactor coolant system and primarycontainment integrity as needed,

USNRC Near Term Task Force proposed Rulemaking changes


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USNRC staff prioritization , Tier 1 actions without delay


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USNRC proposal for SFP instrumentation criteria


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USNRC proposal for SFP instrumentation reliability


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Spent Fuel Pool Cooling Class 1 Level Instrument upgrades(IEEE AC w/potential for DC)- FCI

Spent Fuel Pool Fire Protection and Inventory Control SprayValves- DC Powered Target Rock Solenoid Isolation Valves

Spent Fuel Pool Heat Transfer upgrade- Compact Alfa-LavalPlate and Frame Heat Exchanger, Goulds Pumps, 3L Filters

Hardened Containment Vent Butterfly Valves, Actuators andduct work upgrades

Enertech extended mission 72 hour DC battery operated gasspring EHO upgrades for SBO Hardened Vent Valve cycling

BWR Mark III and PWR IC passive Hydrogen Recombiners(no power supply needed during SBO)- CCI Thermal

Tornado Dampers upgrades

Enertech capabilities

Fukushima response


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Fukushima response

Stored energy, gas spring diversified

Enertech gas spring EH actuator for prolonged station black out

actuator for extended mission 72 hour

cycling of hardened vent valve duringprolonged SBO (without AC power).Will survive and operate followingrestoration of essential AC power.

Low power consumption DC solenoidvalves


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Fukushima response

Enertech gas spring EH actuator for prolonged station black out


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Fukushima response

FCI IEEE Qualified SPF instrumentation

Monitor tank level and temperature simultaneously

Remote calibration minimizes exposure in high radiationenvironments

Remote diagnostics reduce maintenance

Calibrate only when required

No moving parts to wear out

Fewer replacements

60 year qualified life


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FCI dual function SFP instrumentation (level/temperature)


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FCI dual function SFP instrumentation (level/temperature)


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Target Rock DC solenoid operated valves for SFP cooling and spray control


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3L Filters Engineered Filtration Systems

CCI Thermal Technologies

Filter Housings, Media and Cartridges

Strainers and Strainer BasketsAutomatic Self Cleaning Debris Strainers

Engineered Products & Skid Packages Ion Exchange Columns with Resins

Filter DemineralizersOil Water Separators

Emergency Generator Fuel Conditioning Skids

Section III Nuclear Design

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enertech support capabilities for fukushima response

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