It gives the idea about propulsion used in space for faster travel with high propellant efficiency

1. A Seminar on
NUCLEAR THERMAL PROPULSION IN SPACE
Prepared by, Under the Guidance,
Thorat sandip p. Prof:Kadlag R.U.
(Seat no:T120100966)
DEPARTMENT OF MECHANICAL ENGINEERING
AMRUTVAHINI COLLEGE OF ENGINEERING,SANGAMNER
2016-17

2. CONTENTS
1.Introduction
2.Why Nuclear thermal propulsion in space
3.Literature Review
4.Basics of Nuclear Propulsion
I. Basic Nuclear Physics
II. Nuclear Reactor & It’s components
5.Working principle
6.Types of Nuclear Rockets
I. Solid Core Nuclear Thermal Rocket
II. Gas Core Nuclear Thermal Rocket
III. Nuclear powered Electric Rocket
IV. Nuclear Pulse Rocket
7.A Case Study
8.Specific Impulse
9.Advantages and Disadvantages
10.Applications
11.Conclusion
12.References

3. 1. INTRODUCTION
 Nuclear rocket systems include Nuclear thermal propulsion (“NTP”) systems, nuclear electric
propulsion (“NEP”) systems, hybrid NTP/NEP concepts, and nuclear pulse rockets that are propelled
by the force of nuclear explosions.
 Provide thrust through heating of liquid hydrogen propellant by nuclear fission.
 Several designs of nuclear thermal rockets solid, liquid, and gas core nuclear rockets.
 Solid core nuclear rockets operate by pumping the liquid hydrogen propellant through narrow
channels in a solid nuclear reactor.
 As liquid hydrogen moves through the channels, it is heated by the reactor into a high temperature
gas, and then ejected from the exhaust nozzle of the rocket at high speeds.

4. Fig 1.1 Schematic diagram of Nuclear Thermal Rocket
 Liquid and gas core nuclear rockets operate according to a similar principle, but, instead of using a
solid fuel core to heat the hydrogen propellant, they use a liquid or gaseous nuclear fuel,
respectively.

5. 2.WHY NUCLEAR THERMAL PROPULSION IN SPACE
 Can provide electricity, heat and propulsion for future space mission
 Due to high propellant efficiency
 Fast travel method foe human solar system mission
 Reduce fuel consumption and increases payload carrying capacity

6. Sr.no Paper & Author
Name/publication
Year
Description Conclusion
1
“Design of a new
moderated reactor
utilizing an LEU fuel
for space nuclear
thermal
propulsion”:(Feb
2016) Seung Hyun
Nam and etal
Nuclear Thermal Rocket (NTR) propulsion
is option for human exploration into deep-
space because of its high thrust, improved
specific impulse, well established
technology, bimodal capability, and
enhanced mission safety and reliability.
The result indicates that the innovative
reactor concept implement the use of an
LEU fuel and to create comparable rocket
performance, compared to the existing
HEU-NTR designs.
2 “Nuclear Thermal
Rocket Utilizing A
New Moderated
Reactor ”(August
2015):Paolo Venneri
and etal
They gives discussion on a new NTR design
of the second design philosophy, Korea
Advanced Nuclear Thermal Engine Rocket
(KANUTER), for future space applications.
In particular, compared with the LEU-NTR
concept, the thermalized EHTGR of
KANUTER and its low impact of engine
mass increase on rocket performance.
3.LITERATURE REVIEW

7. Sr.no Paper & Author
Name/publication
Year
Description Conclusion
3
“Z-Pinch Fusion
Based Nuclear
Propulsion”(March
2012):J. Miernik and
etal
They have discussed on the conceptual
design of Z-pinch Magneto Inertial
Fusion(MIF) propulsion system.
Fusion-based nuclear propulsion has the
potential to enable fast interplanetary
transportation. The large size of an
interplanetary vehicle dictates that it will be
assembled in space.
4 “Review Of Thermal
Propulsion
System”(September
2015): Roland
Antonius Gabrielli &
Georg Herdrich
This paper gives the past efforts in the
development of Nuclear Thermal Propulsion
systems for space transportation.
Propellant is directly heated by a power
source prior to being expanded which
creates a thrusting force on the rocket.
NTP concepts can be classified with respect
to the underlying process, and with respect
to the design of the heat core.

8. 5.BASICS OF NUCLEAR PROPULSION
 Basic Nuclear physics
Nuclear physics is the field of physics that studies the constituents and interactions of atomic nuclei.
The nucleus is composed of protons and neutrons and has a positive electrical charge.
 Positive protons
 Neutral neutrons
 Bond together by the strong nuclear force stronger than the electrostatic force binding electrons to the nucleus
or repelling protons from one another.
 Fission
Fission is the nuclear process in which heavy nucleous split into two smaller nuclei.
The Fission Products (FP) can be in any combination (with a given probability) so long as the number of protons
and neutrons in the products sum up to those in the initial fissioning nucleus .

9.  Nuclear Reactor
It is an apparatus in which heat is produced due nuclear fission chain reaction.Nuclear reactors are used at
nuclear power plants for electricity generation, propulsion of ships and also in nuclear thermal Rocket Propulsion
system.
 Components of Nuclear reactor
1. Reflector
• Reflects neutrons produced in the
reaction back into the core.
• Prevents neutron leakage.
• Maintains reaction balance.
2.Shielding
• Shielding is required to protect the
working men from the harmful effects
of the radiation.

10. 3. Moderator
• To slow down neutrons from high velocities and hence high energy level which they have on being
released from fission process so that probability of neutron to hit the fuel rods increases.
• Main moderator used:
1.Water H2O.
2.Heavy water D2O(Deuterium oxide).
3.Graphite.
4.Beryllium.
4. Fuel Element
• Contains the fissile fuel.
• Usually Uranium or Plutonium.
• Contains the propellant flow channels.
5. Control Rods
• Contains material that absorbs neutrons.
• Decreases and controls neutron production.
• Controls reaction rate.
• When fully inserted, they can shut down the reactor.
• Examples- Cadmium, lead etc.
Fig 2.2. Nuclear reactor

11. 5.WORKING PRINCIPLE OF NUCLEAR THERMAL PROPULSION
Fig. Working principle of nuclear thermal propulsion
 Stored H2 drawn through pump.
 Supplied to secondary reactor
components.
 Extraction of heat from nuclear
reactor.
 H2 flows primary fuel zone of
reactor core.
 Exhaust through nozzle.

12. Fig.5.1Solid Core Nuclear Thermal Rocket
Fig.5.2 Gas Core Nuclear Thermal Rocket
6. TYPES OF NUCLEAR ROCKETS
1. Solid Core Nuclear Thermal Rocket
 Uses conventional nuclear reactor
 Working fluid is in the solid form
 High temperature heat the working fluid
2. Gas Core Nuclear Thermal Rocket
 Core of NTR is in gaseous form.
 Uses gases fuel.
 Low molecular weight of fuel.

13. 3.Nuclear Powered Electric Rocket
 Also called as Ion Engine
 Nuclear power conversion into electric power
 Low thrust
 Low payload carrying capacity
4.Nuclear Pulse Rocket
 Also known as Orion Engine
 Uses nuclear explosions for thrust
 High thrust
Fig5.3.Nuclear Powered Electric Rocket
Fig5.4.Nuclear Pulse Rocket

14. 7.A CASE STUDY
 Small Nuclear Thermal Rocket Utilizing A New Moderated
Reactor
 Design for Korea Advanced Nuclear Thermal Engine
Rocket(KANUTER).
 Consists of Extremely High Temperature Gas Cooled
Reactor utilizing hydrogen propellant.
 Use of small nuclear thermal rocket gives high thrust, high
propellant efficiency.
 Bimodal Operation Propulsion Mode.
Fig.Schematic View of Korea Advanced nuclear thermal engine rocket

15.  Thermohydrulic Design Features:
Fig. Thermohydraulic analysis models for the
square lattice assembly, fuel wafer thickness;
square flow channels.
Fig.Temperature states as a function of the fuel
wafer thickness in the extremely high
temperature gas cooled reactor.

16. Fig. Thrust estimation as a function of the fuel wafer
thickness of the Korea advanced nuclear thermal engine
rocket.
Fig. Pressure states as a function of the fuel wafer thickness
in the extremely high temperature gas cooled reactor.

17. Fig.Specific impulse and Thrust/Weight estimation as a function of the fuel wafer
thickness of the Korea advanced nuclear thermal engine rocket.
Resultant Discussion:
 By using Extremely high temperature gas cooled reactor in nuclear thermal rocket better propellant
efficiency and high thrust can be obtained.
 For maintaining high thrust the size of square flow channel must be kept minimum.

18. 8. SPECIFIC IMPULSE
 Measure the efficiency of rocket and jet engines
 Impulse delivered /propellant consumed or Thrust generated /propellant flow rate
 Inversely proportional to fuel consumption
 Fthrust=g.ISP.m
where:
Fthrust =thrust obtained from the engine in newtons
g = acceleration due to gravity in m/s2
ISP =specific impulse measured in seconds,
m = mass flow rate in kg/s

19. 9.ADVANTAGES AND DISADVANTAGE OF NUCLEAR PROPULSION
8.1 Advantages
High Isp (2-10x that of chemical systems)
Low Specific Mass (kg/kW)
High Power Allows High Thrust
Use of Any Propellant
Reduced Radiation for Some Missions
8.2Disadvantages
Social Issues
Low Technology Readiness Level (Maturity)
Radiation issues (Shielding)
High Reactor development cost

20. 10.APPLICATIONS
Fig.Nuclear propulsion in car
engine(ford)
Fig.Nuclear propulsion in Rockets Fig.Nuclear propulsion in submarines

21. 11.CONCLUSION
 The nuclear thermal propulsion in rocket gives specific impulse higher than chemical propulsion
system and high thrust/weight comparable to the chemical engines.
 Nuclear thermal designs allow for greater efficiencies in terms of specific impulse, as well as
simpler overall vehicle configurations. The nuclear propulsion system also have the ability of
sustaining large thrust-to-weight ratios, ranging from 5:1 – 35:1.
 The high efficiencies and thrust-to-weight ratios attest that the system can satisfy most mission
requirements, while also decreasing mission lengths by half.

22. 11.REFERENCES
1.Seung Hyun Nam & etal“Innovative concept for an ultra-small nuclear thermal rocket utilizing a new moderated
reactor”(August 2015)
2.Roland Antonius Gabrielli & etal “Review of Nuclear Thermal Propulsion System” (September 2015).
3.C.Bruno & C.Dujarric“In-Space nuclear propulsion” (2013)
4.Seung Hyun & etal “Preliminary conceptual design of a new moderated reactor utilizing an LEU Fuel for space nuclear
thermal propulsion” (Feb 2016)
5. J.Miernik & etal“Z-pinch fusion based nuclear propulsion” (March 2012)
6.https://en.wikipedia.org/wiki/Nuclear_propulsion
7.www.grc.nasa.gov