CN103852094B - The determination methods of a kind of transient high temperature on instrument impact - Google Patents

Abstract

The invention belongs to nuclear power technology field, specifically disclose the determination methods of a kind of transient high temperature on instrument impact. The principle of transmitting based on heat, by determining the heat stagnation time, then determine transient temperature raise time t, by the transient temperature duration in instrument heat stagnation time and containment on recently judging the quick-fried impact on instrument of hydrogen, passed judgment on the availability of instrument under major accident condition. Adopt after this method, the test that does not need the instrument to be correlated with just can be judged the impact on instrument of transient temperature rise under major accident, the method has versatility for the instrument of different size simultaneously, as long as the material of clear and definite meter case and electronic unit are apart from the installation site of shell, just can be by calculating accordingly the heat stagnation time of instrument, greatly having saved test funds, is that one judges under major accident condition, the effective ways of transient high temperature on instrument impact judgement.

Description

The determination methods of a kind of transient high temperature on instrument impact

Technical field

The invention belongs to nuclear power technology field, be specifically related to the definite technology of a kind of transient high temperature on instrument impact.

Background technology

Along with the generation of Three Mile Island accident and Fukushima event, the research to major accident has all been strengthened in countries in the worldDynamics and formulated corresponding severe accident relieving measure, wherein explicitly calls in order to submit necessary informationGive operator, part still needs available under major accident for the instrument of measuring important parameter, continueCarry out its measurement function.

Under major accident condition, other metal material and high in zirconium cladding material and heap in core melt progressionThe water and steam of temperature occurs can produce a large amount of hydrogen after violent chemical reaction, when the concentration of these hydrogenReach after certain proportion, under applicable external condition, may cause blast, have the possibility of hydrogen detonationProperty. Temperature in containment can raise and then fall after rise rapidly within the extremely short time in this case, orContinue to raise, fall after rise repeatedly, form the environmental condition that a transient temperature raises, although the temperature of this transient stateThe degree rising duration is very short, but its peak temperature is very high, and peak can reach thousands of degrees Celsius.

Because the instrument that power plant is used is now all the qualification through benchmark accident, do not pass through similar hydrogenThe qualification of quick-fried condition, and for build and built power plant do not possess yet instrument is re-started relevantHow the condition of testing under major accident, therefore judge that instrument is under the transient high temperature environmental condition of the quick-fried generation of hydrogenWhether can be affected is a crucial technical problem, the at present research of determination methods be mainly concentrate on logicalOvertesting obtains corresponding conclusion, but due to problems such as experimental condition are difficult to imitate, and test cost is hugeMake slow progress at present, therefore adopt a kind of new method to judge that transient high temperature is very must on the impact of instrumentWant.

Summary of the invention

The object of the present invention is to provide one simple, reliable, can improve npp safety and warp simultaneouslyThe determination methods of the transient high temperature of Ji property on instrument impact.

Realize technical scheme of the present invention as follows:

The determination methods of transient high temperature on instrument impact, the method comprises the steps:

1) determine instrument heat stagnation time τ, heat from gauge external high temperature be delivered to internal electrical components timeBetween, its method is as follows:

A) utilize following formula to determine complete wet several Bi of meter body

$\mathrm{Bi}=\frac{h}{\mathrm{\λR}}$

Wherein: h is convection transfer rate, λ is meter case thermal conductivity factor, and R is that meter case is cylindricalRadius;

B) the complete wet several Bi by meter body withIn nomogram, drawFunctional value, utilizes following formulaDraw final excess enthalpy temperature θ_wWith center excess enthalpy temperature θ_mRatio;

$\frac{{\mathrm{\θ}}_w}{{\mathrm{\θ}}_m}=f(\mathrm{Bi},\frac{r}{R})$

Wherein, r is the distance of electronic unit apart from outer surface, θ_wFor final excess enthalpy temperature, θ_mCentered by excess enthalpyTemperature;

C) utilize following formula to obtain the final excess enthalpy temperature θ of instrument_wWith initial excess enthalpy temperature θ₀Ratio;

$\frac{{\mathrm{\θ}}_w}{{\mathrm{\θ}}_0}=\frac{t_{\max }-t_{\∞}}{t_0-t_{\∞}}$

Wherein, t_maxThe maximum temperature that while qualification for instrument, its electronic unit bears, t_∞Environment maximum temperature, t₀For instrument initial temperature;

D) utilize following formula to determine center excess enthalpy temperature θ_mWith initial excess enthalpy temperature θ₀Ratio;

$\frac{{\mathrm{\θ}}_m}{{\mathrm{\θ}}_0}=\frac{{\mathrm{\θ}}_w}{{\mathrm{\θ}}_0}/\frac{{\mathrm{\θ}}_{\mathrm{\θ}}}{{\mathrm{\θ}}_m}$

E) the complete wet several Bi by meter body withIn nomogram, check inUtilize following formula to drawHeat stagnation time τ;

$\mathrm{\τ}=f(\mathrm{Bi},\frac{{\mathrm{\θ}}_m}{{\mathrm{\θ}}_0})\frac{R^2}{\mathrm{\α}}$

Wherein, a is thermal diffusivity;

2) determine transient temperature rising time t, the moment that transient temperature raises rises, and recovers to transient temperatureThe normal moment, time apart between these two moment;

3) quick-fried to instrument to recently judging hydrogen by the transient temperature duration in instrument heat stagnation time and containmentThe impact of table;

If τ is more than or equal to t, the temperature of transient state raises does not affect instrument, can not affect the function of instrument;

If τ is less than t, the temperature of transient state raises and may impact instrument, and instrument exists disabledRisk.

The obtained beneficial effect of the present invention is as follows: the principle of transmitting based on heat, and by determining the heat stagnation timeJudge that whether the transient high temperature that hydrogen detonation burning produces can exert an influence to the performance of instrument, has passed judgment on instrument and has existedAvailability under major accident condition, adopts after this method, does not need the test that instrument is correlated with just canImpact with the transient temperature rise under judgement major accident on instrument, the method is for the instrument of different size simultaneouslyThere is versatility, as long as the material of clear and definite meter case and electronic unit are apart from the installation site of shell, just canWith the heat stagnation time by calculating accordingly instrument, greatly save test funds, be that a kind of judgement is tightUnder heavy emergency conditions, the effective ways of transient high temperature on instrument impact judgement.

Brief description of the drawings

Fig. 1 is the structure chart of pressure inverting instruments and meters;

Fig. 2 is the interior temperature variation of containment under a kind of typical major accident condition;

In figure: 1. cylindrical stainless steel casing; 2. internal electrical components.

Detailed description of the invention

Below in conjunction with the drawings and specific embodiments, the present invention is described in detail.

The structure chart of pressure inverting instrument as shown in Figure 1, pressure transmitter is by stainless steel casing and insideElectronic unit forms, and wherein the high temperature of the quick-fried generation of hydrogen is mainly the electronic unit affecting in involucrum.

According to the principle of thermal conduction study, the heat transfer model of instrument is reduced to endless cylinder here and considers. FigureIn 1, the R of mark is cylindrical radius, and r is the distance of electronic unit apart from outer surface.

1) determine instrument heat stagnation time τ, heat is delivered to the time of internal electrical components from gauge external,Its method is as follows:

A) utilize following formula to determine complete wet several Bi of meter body

$\mathrm{Bi}=\frac{h}{\mathrm{\λR}}$

Wherein: h is convection transfer rate, λ is meter case thermal conductivity factor, and R is that meter case is cylindricalRadius, h and λ can be according to the acquisitions of tabling look-up of different convection types and meter case material.

B) the complete wet several Bi by meter body withIn nomogram, drawFunctional value, utilizes following formulaDraw final excess enthalpy temperature θ_wWith center excess enthalpy temperature θ_mRatio;

$\frac{{\mathrm{\θ}}_w}{{\mathrm{\θ}}_m}=f(\mathrm{Bi},\frac{r}{R})$

Wherein, r is the distance of electronic unit apart from outer surface, θ_wFor final excess enthalpy temperature, θ_mCentered by excess enthalpyTemperature;

C) utilize following formula to obtain the final excess enthalpy temperature θ of instrument_wWith initial excess enthalpy temperature θ₀Ratio;

$\frac{{\mathrm{\θ}}_w}{{\mathrm{\θ}}_0}=\frac{t_{\max }-t_{\∞}}{t_0-t_{\∞}}$

Wherein, t_maxThe maximum temperature that while qualification for instrument, its electronic unit bears, t_∞Environment maximum temperature, t₀For instrument initial temperature;

D) utilize following formula to determine center excess enthalpy temperature θ_mWith initial excess enthalpy temperature θ₀Ratio;

$\frac{{\mathrm{\θ}}_m}{{\mathrm{\θ}}_0}=\frac{{\mathrm{\θ}}_w}{{\mathrm{\θ}}_0}/\frac{{\mathrm{\θ}}_{\mathrm{\θ}}}{{\mathrm{\θ}}_m}$

E) the complete wet several Bi by meter body withIn nomogram, check inUtilize following formula to drawHeat stagnation time τ;

$\mathrm{\τ}=f(\mathrm{Bi},\frac{{\mathrm{\θ}}_m}{{\mathrm{\θ}}_0})\frac{R^2}{\mathrm{\α}}$

Wherein, a is thermal diffusivity, and heat stagnation time τ is now on the electrical component temperature at instrument radius r placeBe raised to t_maxThe required time.

2) after drawing the heat stagnation time, then determine transient temperature rising time t, transient temperature raisesMoment rises, and recovers the normal moment to transient temperature, time apart between these two moment;

Under major accident condition, in containment, may produce the situation that transient temperature raises, Fig. 2 is oneUnder typical major accident condition, temperature variation in containment, can determine continuing of transient temperature by this figureTime, the time period of starting point and the transient temperature that transient temperature is raise between recovering is normally defined as t, notUnder same emergency conditions, can draw corresponding t according to temperature variation in its containment.

3) quick-fried to instrument to recently judging hydrogen by the transient temperature duration in instrument heat stagnation time and containmentThe impact of table;

Determine according to step 1) the maximum (t that gauge internal circuit board rising instrument can bear_max) heatStagnant time, step 2) determine the duration t that in containment, transient temperature raises. It is apparent thus,If τ is more than or equal to t, illustrate that appliance circuit plate institute bearing temperature not yet reaches instrument under major accident conditionWhile identifying the maximum temperature of bearing, in containment, temperature obviously declines, and therefore can specify this winkThe temperature of state raises not to be affected instrument, can not affect the function of instrument, instrument under this emergency conditions stillAvailable. If τ is less than t, the temperature of the transient state under this environmental condition raises and may impact instrument,There is disabled risk in instrument.

Obviously, those skilled in the art can carry out various changes and modification and not depart from this present inventionBright spirit and scope. If these amendments and modification belong to the model of the claims in the present invention and equivalent technologies thereofWithin enclosing, the present invention be also intended to comprise these change and modification interior.

Claims (1)

1. the determination methods of transient high temperature on instrument impact, is characterized in that, the method comprises following stepRapid:

1) determine instrument heat stagnation time τ, heat is delivered to the time of internal electrical components from gauge external,Its method is as follows:

A) utilize following formula to determine complete wet several Bi of meter body

$Bi=\frac{h}{\mathrm{\λ}R}$

Wherein: h is convection transfer rate, λ is meter case thermal conductivity factor, and R is that meter case is cylindricalRadius;

B) the complete wet several Bi by meter body withIn nomogram, drawFunctional value, utilizes following formulaDraw final excess enthalpy temperature θ_wWith center excess enthalpy temperature θ_mRatio;

$\frac{{\mathrm{\θ}}_w}{{\mathrm{\θ}}_m}=f(Bi,\frac{r}{R})$

Wherein, r is the distance of electronic unit apart from outer surface, θ_wFor final excess enthalpy temperature, θ_mCentered by excess enthalpyTemperature;

C) utilize following formula to obtain the final excess enthalpy temperature θ of instrument_wWith initial excess enthalpy temperature θ₀Ratio;

$\frac{{\mathrm{\θ}}_w}{{\mathrm{\θ}}_0}=\frac{t_{max}-t_{\mathrm{\∞}}}{t_0-t_{\mathrm{\∞}}}$

Wherein, t_maxThe maximum temperature that while qualification for instrument, its electronic unit bears, t_∞For environment maximum temperature,t₀For instrument initial temperature;

D) utilize following formula to determine center excess enthalpy temperature θ_mWith initial excess enthalpy temperature θ₀Ratio;

$\frac{{\mathrm{\θ}}_m}{{\mathrm{\θ}}_0}=\frac{{\mathrm{\θ}}_w}{{\mathrm{\θ}}_0}/\frac{{\mathrm{\θ}}_w}{{\mathrm{\θ}}_m}$

E) the complete wet several Bi by meter body withIn nomogram, check inUtilize following formula to drawHeat stagnation time τ;

$\mathrm{\τ}=f(Bi,\frac{{\mathrm{\θ}}_m}{{\mathrm{\θ}}_0})\frac{R^2}{\mathrm{\α}}$

Wherein, a is thermal diffusivity;

2) determine transient temperature rising time t, the moment that transient temperature raises rises, and recovers to transient temperatureThe normal moment, time apart between these two moment;

3) quick-fried to instrument to recently judging hydrogen by the transient temperature duration in instrument heat stagnation time and containmentThe impact of table;

If τ is more than or equal to t, the temperature of transient state raises does not affect instrument, can not affect the function of instrument;

If τ is less than t, the temperature of transient state raises and may impact instrument, and instrument exists disabledRisk.