Into Unscientific Chapter 587

  Chapter 587 The authority is really wrong!

  “.The authority is wrong?”

   This underground secret room.

   Following Xu Yun's words.

   This time.

   It was no longer Lao Guo who was astonished, but

  All members of the project team gathered around the table, including Lu Guangda, the two men who were at war before, and others.

  There is no other reason.

  Gein Xu Yun's words are really...too impactful.

   Was the theory devised by Norris Bradbury wrong?

How can this be?

To know.

   Norris Bradbury is the director of the Manhattan Project whom Oppenheimer personally ordered. He personally assembled the plutonium detonator at the center of the first atomic bomb test in human history.

It can be said like this.

  No one, except Oppenheimer, understood the atomic bomb theory better than Norris Bradbury.

   This is a big guy who is bound to be recorded in the history of human science.

  He is like a big mountain in front of everyone, and any pedestrian who sees this peak will only sigh with admiration—even for Lao Guo and Lu Guangda.

   At least for now.

   The result was unexpected.

  Xu Yun, the 'Foolish Old Man' suddenly jumped out, pointed to the mountain and said that its location is wrong, it should not be there.

   This is obviously quite an astonishing statement.

  At this time, Xu Yun seemed to be in a vague posture of not being surprised and dying. Facing the astonished crowd, he continued to speak:

   "Guo Gong, Director Lu, why can't authority be wrong?"

   "It is true that Norris Bradbury and Oppenheimer have completed the Trinity and the Manhattan Project, and there is no doubt about their ability."

   "But don't forget that this steady-state critical state model is just the frontier theory of atomic bomb research, and it has not been implemented technically."

   "So theoretically, why couldn't Norris Bradbury be wrong?"

"even."

   Speaking of which.

  Xu Yun deliberately paused, and looked around:

   "Is there a possibility that the theory on the other side of the sea cannot be iterated in application, because some of the links are actually problematic? So it can't be adapted in reality?"

   Xu Yun finished speaking.

  The edge of the table became instantly audible.

   This silence forms an extremely delicate picture under the contrast of the abacus and the discussion sound in the distance.

   After a long time.

  Lu Guangda had just recovered from his astonishment, and he and Lao Guo looked at each other.

   It is not an exaggeration to say.

  Xu Yun's words were so impactful that they even shook their cognition.

But on the other hand.

   Undeniable.

   Although Xu Yun's words are difficult to accept cognitively, they are indeed logically possible.

  According to the information voluntarily disclosed by the sea.

  The Manhattan Project adopted an approximate solution for the neutron transport equation, that is, a parallel SN algorithm in a two-dimensional spherical coordinate system.

  This solution uses a combination of region decomposition and parallel pipeline to calculate the degree of parallelism in the space-angle direction, and the parallel efficiency is about 52%.

  At the same time, this method has a high error rate. The higher the magnitude, the more likely errors will occur, and it is bound to be eliminated.

   So it is the same as choosing the more difficult to develop uranium bomb over the plutonium bomb.

  The theoretical group led by Lu Guangda rejected this parallel algorithm, and prepared to recreate a set of theories that can be used for a long time.

   By the way.

  Later, Gaul did not raise the white flag in this regard, and also gave up the parallel SN algorithm—but John Bull took a trick and continued to use this method.

   Then a while later.

  Lu Guangda took a deep breath, forced himself to calm down, and asked Xu Yun:

   "Comrade Han Li, since you think there is a problem with this model, can you find out what went wrong?"

  "After all, there is no evidence for what you say, and everything must be based on evidence."

  Xu Yun pondered for a moment when he heard the words, and finally shook his head lightly:

   "Director Lu, I'm sorry, due to the limited time, I will definitely not be able to find out the core error for you."

   "After all, I am not an omniscient and omnipotent **** or a time traveler from the future, so I can know everything in advance."

   "But I'm sure. At least there must be something wrong here."

   Say it.

  Xu Yun stretched out his index finger and lightly pointed to a certain area on the calculation paper.

   Lu Guangda subconsciously poked his head over for a few glances, and was slightly taken aback:

   "High compression thermonuclear fusion region?"

  Xu Yun nodded, picked up a pen and drew a horizontal line on a parameter, and began to explain:

   "Look here, the flow density of the collapsed density is 1.533, right?"

  Old Guo nodded.

  Xu Yun wrote again:

   "Look, let's first define a transport mean free path, insert the mean scattering angle cosine, neutrons will have an extrapolation distance d=2λtr/3."

   "The root of the reciprocal of the characteristic coefficient, let alone the specific value, the number of extrapolated neutrons must be smaller than the number of divergent neutrons in the center A area, so how can the calculated number be greater than 1?"

   "So obviously Norris Bradbury must be undercounting. Some divergence scenario."

   Lu Guangda's pupils shrank suddenly.

   Mentioned earlier.

   Since this framework was calculated by Norris Bradbury.

  So after getting the document and translating it, Lu Guangda and the others simply checked it once and used it directly.

  After all, this document has promoted the progress of many stuck projects before, and it cannot be something that has been tampered with like a gas exchange membrane.

  This approach is like you want to use a computer to design a physical model, and one day you happen to get a host.

  This host has passed preliminary testing, and there are no problems with running points, starting, surfing the Internet, and downloading videos.

  So although you are curious about its internal structure, because the design of the physical model is important, you don't care about the specific parts and use it directly.

   And the link that Xu Yun pointed out now is equivalent to telling them:

  Dear, there is a problem with a certain thread of the CPU of this computer—it's not that someone deliberately tampered with it, but that the manufacturer made a mistake in the production process, and the manufacturer may not even know it~

  Think here.

  Lu Guangda couldn't help picking up the manuscript paper and pen in front of Xu Yun, and looked at it seriously.

   Well known.

   The framework of the neutron transport equation is very broad, but there are not many particularly important concepts in it, only a dozen or so.

   And in these concepts.

   Logarithmic reduction is undoubtedly a very important concept.

  It refers to the energy loss rate when neutrons move in matter, and the expression is u=lnE0/E.

   Among them, E0 is the energy before neutron scattering, E is the energy after neutron scattering, and u is the logarithmic energy drop.

  After having the concept of being able to drop.

   Then you can define the average logarithmic energy drop of a certain substance.

   is the average energy drop produced by each scattering of neutrons and such atoms:

  ξ=Δu≈2/(2/3).

  This is an approximate calculation formula for the average energy drop, which can be used for atoms with atomic weight A greater than 10.

   In this way, it can be calculated how many times neutrons need to be scattered on average to drop from E0 to the specified E when a material made of a certain atom is used as the bullseye:

  Nc=u, ξ=lnE0lnEξ.

for example.

   The neutron slows down from 2MeV (the average energy of fission neutrons) to the energy drop of 0.0253eV, which is u=lnE1/E2=18.1856.

Of course.

  The concept of energy reduction has also undergone some conceptual iterations in later generations, and is more widely used in the field of reactors.

  However, this concept is still very mainstream in this era, and the version will not be updated until the 80th century, both at home and abroad.

  And for a de-energized neutron.

  Its "lifetime" will go through two processes of slowing down and diffusion.

   Among them, the average time of slowing down is called the slowing time, and the average time of diffusion is called the diffusion time.

  Neutron lifetime can be expressed as slowing time plus diffusion time—this should be regarded as the addition of the difficulty of the first grade of elementary school.

   In other words.

  The time that neutrons exist in a nuclear reaction can be obtained by dividing the free path by the moving speed, that is, integrating the average energy drop.

   Wait until this step.

  A crucial concept emerges.

   This is also a concept that appears widely in quantum mechanics, fluid mechanics, and electrodynamics:

  Flow density, j=ρv.

  The so-called current density refers to a quantity that can be used to describe the change of physical quantity in the system.

   You can see its meaning from its appearance:

   Density times velocity.

  Density represents microelements, while velocity is perpendicular to the system boundary, which represents microelements leaving or entering the system.

   In nuclear engineering.

   Taking neutron density as n, then there is neutron flux density, which is also neutron flux density neutron=nv neutron/(ms).

   is the number of neutrons passing through a unit area per second.

  Since the neutron flux density can measure the change of the neutron level in the system, combined with the macroscopic cross-section Σ has the physical meaning of the reaction probability, so the nuclear reaction rate R neutron R=Σneutron/(ms) can be defined.

  This represents the probability of a nuclear reaction, that is, how many neutrons are reacted per unit time per unit volume.

  This concept is very simple and easy to understand.

  What Xu Yun pointed out is that the contrast difference of neutron density in the two steps is abnormal.

   Still give an inaccurate but easier-to-understand example to describe this situation:

  Suppose your name is Li Ziming, and you study in the second class of the third grade in an elementary school.

  Your class is on the third floor of the teaching building. There are dozens of identical classrooms in the whole teaching building, and there is only one entrance on the first floor.

   Then the steps for everyone to go to the class must be like this:

  Pass through the entrance on the first floor, go up the stairs to the respective floors, and then enter your own class.

   That is.

  A certain period of time.

  The number of people entering the classroom of Class 2 of the third year must be much smaller than the total number of people entering the teaching building from the first floor.

   In other words.

  The ratio of the two is not to say a few to a few, it must be less than or far less than 1-a class is counted as 50 students, and there are at least hundreds of people who walk into the teaching building.

   But the framework calculated by Norris Bradbury is different.

  It shows that the ratio is greater than 1, which is equivalent to more people entering the class than the teaching building, so this is obviously something wrong.

   "n(r,t/)t=S(r,t)Σa(r,t)J(r,t

   "Add a steady state situation/t=0, then there will be d2(r)dr2+2rd(r)dr(r)L2=0"

   "Introduce Fick's law. So take the neutron flux density (r, t) as the function to be found, rewrite the continuity equation as 1/v/t=SΣD4"

   Write here.

  Lu Guangda's pen tip suddenly exerted force, piercing a hole in the calculation paper.

  But Lu Guangda, who is extremely frugal on weekdays, did not show the slightest distressed expression this time, but stared at the formula he had calculated.

  1/v(/t)=SΣD4.

   This formula may seem strange at first glance.

  But if the 4 in the last [4] is removed, many smart students will recognize it.

   That's right!

   This is the starting point of all nuclear engineering, one of the most important equations in nuclear engineering physics

   Neutron diffusion equation.

  It describes the variation of the neutron flux density distribution, and it is a second-order differential equation in space, and in some cases it can be transformed into the Helmholtz equation to make a wave solution.

  At the same time, it is a first-order differential equation in time, and the monotonic development in time can be obtained.

  Generally speaking.

  For any complete framework, you can deduce the correct expression of this formula from it.

but

  Currently, the result released by Lu Guangda has an extra 4!

   There are more than 4 in the differential equation, and this concept will be sprayed with water if it is explained again.

all in all.

   This is an impossible situation anyway!

To know.

  These derivations of the theoretical department are not all mathematical calculations. Many of the parameters they calculate come from the experimental team in the application zone—otherwise, the rabbits would not need to build a detonation laboratory.

  For example, Lu Guangda and the others used the parameters this time.

  Some of these parameters come from the files sent back across the sea, and the files originally belonged to some national-level experimental institutions.

   Some of them come from the materials they brought back when they went to Maozi for further study seven or eight years ago, such as the Petrov reactor.

   There are also some from the neutron physics laboratory of the No. 7 Branch Factory, which is in the workshop next to Lu Guangda and the others.

  Many of these data are parameters of real nuclear explosions, that is, facts that have already happened—no matter how bad they are, they are cold explosion data.

  There is a problem with the results of the inversion of these facts, and it is obviously impossible to be the fault of the data.

   That is to say

   Norris Bradbury's framework does have some mistakes!

  These bigwigs on the scene are all top domestic elites, so they soon realized this one after another.

  See this scenario.

   There is no need for Xu Yun to remind again.

  Lu Guangda looked at the crowd, showing his decisive side, and quickly gave various instructions:

   "Hi Lai, now you lead the second group to retest the cosine of the average scattering angle!"

   "Comrade Chen Rui, you are responsible for verifying the dimension of the diffusion length."

   "Old Hua, go and calculate whether the superposition state of the eigenwave is continuous—well, don't try to introduce an effective multiplication coefficient."

   "Lao An, you take Xiao Gao and the others."

  Seeing Lu Guangda who quickly entered the state, Xu Yun couldn't help feeling a little emotional.

  As expected of the leader of the theory department.

To know.

   To avoid exposing too many exceptions.

  Xu Yun this time just gave a mistake that seems obvious at first glance, but actually involves a lot of mistakes.

   There are at least 20 or 30 calculation modules for the radiation of this error point. In addition to the complexity, the number alone far exceeds the number of teams in this room.

   The result was unexpected.

  Lu Guangda unexpectedly made arrangements so quickly, and the directions mentioned are at least 80% correct!

   This is purely in the category of professional instinct, and requires a solid and strong accumulation of knowledge to achieve this step.

  Even in the world at this time, there are not many people with this strategic instinct.

   There must be five fingers, but not necessarily ten fingers.

   Soon after.

  The entire laboratory was quickly mobilized.

   Among them, the most exciting performance is undoubtedly the two big bosses who had quarreled before and their team members.

   That is, Hua Yun, who was the leader of the second group of the theoretical department at that time, and Ma Ruiping, who was the leader of the third group at the time.

  Hua Yun is currently one of the few leaders in China who has obtained a Ph.D. in theoretical physics and functional analysis at the same time. Although he is not a member of the academic department, he is very capable.

   In terms of functional analysis, he can even be said to be the base. Even the first person in China!

  Ma Ruiping is an applied mathematics expert who graduated from Michigan State University. Due to his solid oral and written English skills, he is now mainly responsible for the translation of foreign language journals.

  Although Ma Ruiping of the later generations was not rated as an academician, he was only an ordinary deputy senior title until he retired, and it was not even officially declassified until 2022.

  However, in the entire 596 project, his translation of foreign language documents accounted for as high as 70%, which can be described as an outstanding contribution.

  Because the problem was not found before.

  Hua Yun, Ma Ruiping and the group behind them all received a lot of pressure—otherwise they wouldn't have questioned each other.

   This kind of doubt is based on the confidence in one's own ability, and secondly, because the analysis of this document is too important, no one wants to take the blame.

   Now that the culprit who caused them to be hacked is discovered, how can they not be excited?

   So fast.

  The entire project team stopped their work and began to do calculations.

"Ci(r, t) t=βik∞Σa(r, t)λiCi(r, t)i=1, 2, 3, ., m Brother Wang, please give me the files of group 3 on Maoxiong's side !"

"Everyone, the space part is the Helmholtz equation, and the general solution is the superposition of a series of standing waves, that is, the superposition state of a series of eigenwaves, so if we want to ignore it and study the change in time, it is equivalent to assuming that the whole process The neutron flux density constitutes an overall wave, and each point changes synchronously, then we should"

   "Xiao Zhao, do you want to go to the bathroom together later?"

   "0.557, 0.559, 8.322, report, there is an obvious bulge in the calculation process!"

   "Good, what is the density vector?"

   "There is only an approximate interval, it should be around 18.5-19.7!"

   "Abaa aba."

   Watching the scene in full swing.

  Xu Yun couldn't help but focus on the piece of paper in front of Lu Guangda again.

   That is.

  Record has an English facsimile by Norris Bradbury.

to be honest.

  In 2023 of the hereafter.

  Xu Yun did not know the existence of this document, which is the steady-state subcritical state model designed by Norris Bradbury.

   This is actually quite normal.

  After all, there are too many twists and turns and stories in the development of nuclear weapons. Many things have not been declassified even by 2023—some may have been declassified, but they have not been fully disclosed, and it is very complicated to inquire.

  What Xu Yun can know is only the surface of these things, that is, many comrades sacrificed their precious lives to protect those foreign periodicals from being shipped back to China smoothly.

   As for the general content of these periodicals, it is impossible for him to fully understand them.

But on the other hand.

  According to some of the later achievements of the rabbits, Xu Yun can roughly compare certain situations.

   For example, the correction of the well-known supercritical amplification effect.

  Xu Yun didn't know which incident this was the result of, and he couldn't even remember who the team leader who corrected it was.

  But if one day encounters an event related to the critical adjustment error of the group parameter, then this event must be related to the correction of the supercritical amplification effect.

It's like one day you traveled to a certain era, and you didn't know anything about the surrounding scenery and characters, but someone next to you said to you [Marshal, Huanggutun is ahead], you can definitely guess how many times it is. several years.

  The same is true now.

   Although Xu Yun did not know the critical state model of the stationary state designed by Norris Bradbury in advance.

   But from this point of error, it is not difficult to judge that this error must be related to that incident.

   And if that's the case

  Think here.

  Xu Yun's heart suddenly beat rapidly.

etc!

  If the conditions are right.

   It seems that maybe maybe maybe I can take the opportunity to make another big deal?

  If that can be done.

   The help to the rabbits may not be inferior to that of defeating U2!

  Afterwards, Xu Yun carefully thought about the information learned by later generations, and felt more and more that there was something to this matter.

Of course.

  This matter is of great importance, involving many aspects, and the difficulty is no less than that of the later generation Xu Yun.

   So how to operate it still needs to be carefully considered.

At least

   From the current point of view.

  Even including the fact that Lu Guangda and the others are verifying, this idea still lacks a piece of the puzzle.

   Two hours later.

   Hua Yun not far away suddenly raised his head and shouted to Lu Guangda:

   "Director Lu, I have found the cause of the problem!"

  Lu Guangda straightened his expression immediately, and quickly asked:

"what reason?"

  Hua Yun quickly brought the result calculated by his team to Lu Guangda, and slapped it heavily on the table:

   "Director Lu, look!"

   "The steady-state critical state model designed by Norris Bradbury is a weak field approximation, which can only achieve a good description effect in the region where (r, t) changes slowly."

   "But look at these three data sets, they are the experimental results of Mao Xiong, Dian Dian Hai and our own."

   "These results show that the source. That is, S(r, t) interacts nonlinearly with the neutron flux density (r, t)."

   "In addition, in the area very close to the source, there are also areas where (r, t) changes drastically such as near the control rod, and the change is essentially nonlinear!"

   "That is to say. Norris Bradbury across the sea used a linear equation to describe a nonlinear situation!"

   "Authority. Something went wrong!"

Note:

  I replaced part of the process with the reactor principle, and everyone understands the reason.

  (end of this chapter)

Chapter end