Military & Aerospace

Nuclear Submarine Ahoy: Whither Bound?
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Issue Vol. 35.4 Oct-Dec 2020 | Date : 15 Jan , 2021

The idea of nuclear propulsion for ships and aircraft for India was first mooted by Dr Homi Bhabha in 1954. In 1965, he sought assistance from US Atomic Energy Commission for developing nuclear propulsion technology. This was turned down. This should have been no surprise – as at the time, the US was unwilling to share this technology even with its close NATO ally, France. In 1968, the idea remerged, when the Prime Minister, Indira Gandhi assigned to the Committee on Science and Technology (COST) – the task of identifying cutting edge technology areas in the field of S&T. She emphasised the priority being given to defence-oriented technologies. The Director of Marine Engineering (DME) NHQ chose to propose nuclear propulsion for submarines (s/m) as one of the thrust areas. At that stage, officially no specific platform i.e. Nuclear Attack s/m (SSN) / SSGN or Ballistic Missile s/m (SSBN) was projected except that it was for s/m propulsion. The understanding was that the Indian Navy (IN) along with Bhabha Atomic Research Centre (BARC) would start work on a feasibility study. The strategic difference between the sea control role and strategic deterrence role was none of their concern, at that stage.

There is a common belief that the genesis of a nuclear powered s/m for the IN was laid in 1968, when the Soviet Defence Minister (DM) Marshal Grechkov and Admiral Goroshkov on a visit to India gave Prime Minister Indira Gandhi the impression that the USSR was willing to assist India in acquiring a nuclear powered s/m fleet. It is claimed that a note verbale to this effect was submitted to the – Prime Minister1, but she was non committal at this stage2.

Advanced Technology Vessel Programme (ATVP)

By 1971, the environment had become even more favourable. Admiral Goroshkov had clearly demonstrated that the mere presence of just one Soviet SSN in the Indian Ocean was able to compel the US carrier battle group to withdraw from the Bay of Bengal from threatening Indian action in the Bangladesh liberation movement. As far as the Prime Minister was concerned, this was presumably the prime factor that convinced her of the importance of a nuclear submarine for the security of the nation.3 The following events gave further impetus to the proposal:

  • The Indo-Soviet Treaty of Peace, Friendship and Cooperation was signed on 09 August 1971.
  • On 25 February 1972, the Soviet DM Marshal Grechko is reported to have boasted to Field Marshal Manekshaw during his visit to Moscow, that, “If we have an alliance, I shall earmark 50 Inter Continental Ballistic Missiles (ICBM) to your defence against China.”4
  • In parallel, the potential silo keepers for the nuclear war-heads programme were, advocating restraint to the Prime Minister – primarily, impressing upon her the fact that without all the other elements that are needed for completing the deterrence system – merely carrying out one nuclear explosion would achieve nothing.5
  • On 15 November 1972, Prime Minister Indira Gandhi declared to the Parliament the decision to conduct a Peaceful Nuclear Explosion (PNE) and that nuclear propulsion design for s/m was under examination.
  • In 1974, the People’s Liberation Army Navy unveiled its SSN.
  • Pokhran I PNE was conducted on 08 May 1974.
  • Civil nuclear cooperation with USSR was initiated in 1976.
  • On 22 January 1976, the financial allocation for the Pressure Water Reactor (PWR) project was steered through the Planning Commission by V Admiral Tandon the Chief of Material (COM) NHQ.6
  • In October 1979, in Moscow, Secretary Defence Production K Subrahmanyam broached the subject of seeking Soviet technical assistance on the nuclear s/m. Admiral Goroshkov is believed to have given a positive response.7
  • It is reported that in May 1981, Marshal Ogarkov the Soviet Chief of General Staff, enunciated to Prime Minister and Raksha Mantri (RM) – the Ogarkov Principle8, indicating the extent of Soviet assistance that was feasible on nuclear s/m.
  • The Integrated Guided Missile Defence Project (IGMDP) and Advanced Technology Vessel Programme (ATVP) were launched in July 1983 and April 1984 respectively.

A Debate on Choice of SSN vs SSBN for India

Till the 1990s, there does not seem to be any evidence to show that there was any formal directive calling for SSBN. The formulation of the technical assignment for S2 in 1982 could be considered as the first indication – leading to a strong school of thought that perceives that the primary objective indeed was to fulfil the strategic deterrence role. And that the official stand of choosing the sea denial role, was merely a subterfuge, a front and a stepping stone at that. In the Indian context, taking precedence into account, a parallel could be drawn with the way issues like, the nuclear tests, biological warfare material stockpile creation, its ultimate destruction and the SSBN, were handled with least publicity or institutional military participation.

The evolution of SSBN is a progressive process commensurate with the actual development in the respective silos. As would be shown later, working in four semi-autonomous silos linked horizontally under the Prime Minister’s Apex authority for each – was the order of the day. Presumably, declaration of intent was accordingly tutored in unison with the developing scenario.

As a devil’s advocate, the other arguments in favour of a contrarian point of view are as follows:–

    • With data unearthed from archives across the globe and interviews with erstwhile, senior scientists and naval officers, some scholars have argued in favour of the SSN9  option. That only gives the official front of the respective establishment at the time.
    • A few have written in favour of SSBN.10,11,12 The jury is still out on the bottom line.
    • Also, nearer home, operationally the IN was genuinely concerned with acquiring sea control / denial capability in the Indian Ocean.
    • In any case, that should not have precluded the strategic thinkers from strategising over the need for an SSBN and Submarine Launched Ballistic Missile (SLBM) to deal with a future China (PRC) scenario with SSBN. The PRC’s roadmap was unambiguous and is backed by the US intelligence reports13 at the time.
    • From the very beginning, the Personal Private Secretary to the Prime Minister, PN Haksar14 was an advocate for taking the SSBN route. Both for domestic and geo-political reasons such a decision if and when taken, could not have been made public.
    • If Haksar15 a civil servant in the 1960s, could visualise the need for a sea-based nuclear deterrence requirement then imagining that such a thought would not have crossed the minds of naval strategists is being naive.
    • It would be recalled that in the context of initiating a nuclear weapons programme itself, there was intense dialogue within the PMO even in the 1970s. At that stage, to expect publicising of a SSBN programme was out of question.
    • So much more the reason, to give due credit to the top political leadership for having taken such a bold plunge
    • It would be observed that Chiefs of Staff Committee (COSC) report of 198216 had given an assessment that mere possession of nuclear weapons is not good enough unless an appropriate means of delivery are also available. This does not preclude the SLBM.
    • With the meagre naval budget, the IN could hardly be expected to be able to support even a one standard carrier battle group. In those circumstances, vocalising the need for a SSBN/SSN would have been a pipe dream.
    • In that context, the Chief of the Naval Staff(CNS) Admiral Pereira’s stand17 in 1981/1982, opposing the timing for inducting a SSN into the IN, is to be seen in that light. His apprehensions were accentuated by the to and fro throwing of the ball between DAE and MOD on who will pay even for the Marine Engineering Reactor Project on the floor of the Planning Commission meeting earlier.
    • The appreciation would have been totally different had the then Government unambiguously declared, at that point of time, to at least the top Naval leadership, that this was a National Project of strategic importance and would be delinked from the naval budget for perpetuity. Similarly, it is difficult to imagine that a government, which not so long ago, was being adamant in not providing the IN with a conventional s/m for even ASW training purposes, would suddenly propagate investment in a multi-billion dollar nuclear s/m project dedicated to merely giving the IN a sea control/denial capability. That too, against the wishes of the incumbent CNS.
    • Unless the final objective was a much higher national strategic goal which could not be disclosed prematurely.
    • The first time the Parliament was enlightened about the nuances in the role of a nuclear s/m in a sea denial/strategic deterrent role was on 06 December 198318 when the RM is reported to have informed that:
      • “I have already said that we keep our option open in this matter; if necessary, we will go for it.” (This seems to be a similar position taken by Prime Minister Nehru in context of developing a nuclear bomb.19)
      • And explained the nuance between SSN and SSBN.
    • It is considered that the provision of vertical launch capability sought for the s/m was a giveaway of our ultimate intentions. It is claimed that this stipulation was for a cruise missile SSGN. The hidden objective would have been to get access to technology related to under water ejection for a vertical launch SSM system. A clandestine first baby step towards the SLBM objective.20
    • A dispassionate assessment would also lead to the conclusion that such a provision in the Technical Assignment would also mean higher displacement for the boat leading to lower speed limits – not compatible with the ASW/SSK role envisaged for the boat (SSN). This fact about the contradiction in the performance limitations would have subsequently been substantiated – when the time came for conceptualising the real indigenous SSN after meeting the SSBN requirements i.e. in respect of S4 and S5.
    • The simultaneous emergence of IGMDP and ATVP also on identical management models – were not considered to be a mere coincidence.  Silo 3 embryo started forming on 17 February 1976 when Aeronautical & Missile Development Research Board (AMDRB) under chairmanship  of the PM was established. That was followed by the formation of the Missile Policy Committee – which  emerged as the IGDMP. Further, the weaponisation of the PNE being progressed in a different silo fitted into the master jigsaw plan – falling into place, at the appropriate time.
    • The absence of a mention of the triad in General Sunderjee’s report in 1985, is another reason assumed by some of the scholars – for SSBN/SLBM not being on the card. At the time – even Agni series was nowhere in sight. Could one on that basis conclude that India had no intention of developing an ICBM?
    • The 11 May 1998 – Pokran II – Shakti exercise was being pursued in yet another silo. Soon thereafter, Prime Minister Vajpayee had formally proclaimed, while inspecting progress of Prototype Training Centre (PTC) at Kalpakam – of the SSBN role for S2.21
    • In 1998 – the reality started becoming palpable globally.22 The process, of going from Sagarika the cruise Sub-surface to Surface Missile (SSM) (K15) to K5 > K6 and adding a plug to extend the hull to accommodate larger numbers/size SLBMs, had begun.
    • The genuine indigenous SSN design also started taking shape.
    • After all – PTC and S2 (Arihant) were both originally conceived as a technology demonstrator in their respective silos.
    • The nuclear s/m programme, in totality, needs to be viewed in four separate parallel silos23 – as illustrated later:
        • Propulsion – PWR (PTC) > S2 >> S5 > S6 > SSN.
        • S/M Platforms – SSGN (S2) >>SSBN (S5)24 > (S6) on to SSNs.
        • Weapon carrier – SSM / SLBM. – (Sagarika) K15 > K4 > K5> K6.
        • Nuclear war heads for K15 > K4 > K5 & >K6 etc along with (MIRV) Multiple Independently targetable Re-entry Vehicle.
  • Each of the silos was programmed to be managed by their respective independent professional teams. Each Project at the apex level was directly responsible to the Prime Minister. Sharing of information horizontally was purely governed by the need-to-know basis.25
  • The Prime Minister provided a closely knit horizontal linkage to eventually provide the composite solution and an integrated programme.
  • The timing of each activity had to be sequentially planned to dove-tail into the micro/macro level PERT network.
  • At the concept design stage of the s/m, if one finds that the IN/DRDO did not seem to have initiated any R&D work on SLBM as yet – did not preclude SSBN being on the card, as the endgame. For that matter, at that point of time, when Silo 1 was initiated – neither had any R&D work on any of the remaining silos been initiated. If one is seeking an answer to these questions – other indicators have to be investigated also.
  • Design/building of a nuclear s/m involves a complex multidisciplinary process. Technology in none of the disciplines concerned existed in the country. For that matter, in early 1967, the Indian Navy had not yet ventured into the realm of even operating a conventional s/m. In every discipline, – we were to begin from scratch. At that stage, to reveal our final strategic objective would have been catastrophic. Even the USSR, would have slammed its door shut had we told them that we were looking for TOT on SSBN. Hence, we had to play the game with our cards close to our chest.
  • If from the inception, the primary objective was SSN/SSGN, then there was nothing preventing India from continuing on that track from S2 (a technology demonstration model) to a genuine SSN/SSGN.
  • Transformation of S2 to S5 (SSBN) entails retention of S2 architecture and inserting a SLBM plug. That replicates the conversion of an Akula SSN hull design into Borey SSBN.26 It is reported that the transformation to Borey resulted in speed loss of about 14 percent.
  • Ultimately, only in February 2015, after the SSBN commitment with S5 and S6 was in sight, the government approved the construction of the genuine SSNs. In February 2020, the Economic Times reported that preliminary design phase for the SSN had been completed by Submarine Design Group.27
  • On completion of the Arihant’s maiden deterrent patrol in November 2018, Prime Minister Modi finally declared that India had achieved its objective of a nuclear triad.

The silo matrix statement presented later28 capsulates the jigsaw puzzle in totality for the period 1969 to 2025 – chronologically, illustrating the horizontal linkages across the four silos and gives full credence to the devil’s advocate hypothesis.

A Comparative Performance Statement

A comparative statement in respect of a projected nuclear s/m programmes for USN and a conventional s/m for the Royal Australian Navy (RAN) planned for execution in the 21st century is presented below.29

RAN SS Arihant
1.            Design duration 15 yrs 20 yrs 15 yrs 14 yrs*
2.            Number of designers at Peak load 3000 1000 NA ~500*
3.            Overall design man hours 30 mm 30 mm + 30% 12 mm NA
4.            Build period 7 yrs 7 yrs 7 yrs 18 yrs*
5.            Total period 22 yrs 27 yrs 22 yrs 32 yrs

Taking into account India’s starting point on the learning curve, the severe technology denial regime in place and comparatively small number of designers employed, the overall performance is considered laudable. A total period of 32 years taken by the Arihant with around 500 designers as opposed to 27 years allotted to the US Variant B with 1,000 designers is considered reasonable.

On hind sight, had we from the beginning exercised the Spaasky option for the PWR and SDG accepted unbridled  support from the Consultant’s  Design Bureau, same as resorted to after 2000 – would have resulted in a saving of at least five years. These options were available all along but not availed of due to mis-guided national pride and over confidence in ones design capability.

Fuel Choice Dilemma

On the basis of contemporary practice on nuclear s/m inservice, it was considered that enriched uranium-based plate type fuel package was the optimal choice for s/m PWRs. At the initial stages of the Project, India had serious constraints on ready availability of enriched uranium and BARC had no expertise on production of plate type fuel element. Hence, perforce the rod type of fuel was chosen for the PTC with the expectation that the plate type would be developed for the s/m PWR.

The availability situation for enriched uranium is now quite satisfactory. But thirty-seven odd years down the line, whether due to financial constraints or inadequate pressure from the user, there seems to be no movement towards upgrading to plate type fuel package.

Explanations, such as difficulty in fabrication and it being more susceptible to leaks, are not considered sufficient grounds to abandon the effort to develop a more efficient/safer system. Especially, since we are now venturing into newer domains that require much higher power and re-engineering would be unavoidable. The technology demonstration solutions acceptable then, under severe technology denial regime, cannot be perpetuated forever. DAE should not be permitted to rest on their oars and relax on the s/m safety standards on this count unless globally the technological assessment of the fuel packages itself has now veered away, in favour of the rod type fuel solution.

The above also needs to be looked at along with the offer purported to have been made by the French earlier, against the offset provision of the Scorpene deal.30 Similar possibility could be explored now in respect of acquiring TOT on plate type fuel package for the PWR against the offset clause when negotiating for the Project 75I.31 In case the new DPP 2020 with specific reference to alterations in the off-set clause for strategic partnership model comes in the way – then alternatives such as abinitio single venture / quid pro quo basis would have to be resorted to.

For the larger SSBN on the anvil i.e. S5 and S6, one could standardise on the existing PWR1 and opt for a two PWR solution or for a new larger PWR2. One would recall that the two PWR was an option considered earlier, but rejected on the grounds that such a change mid-stream would result in infructuous re-work that would further lead to high cost/time over runs.32 A post-mortem of that decision would have some lessons also.

Power enhancement could also be achieved by using higher enriched uranium. That would further improve the time between refuelling and the operational availability of the s/m. In any case, for the SSNs, it would be considered necessary to go in for a plate type fuel package option especially to fully satisfy the safety and performance criteria. Even if we can live with poorer performance norms for the SSBNs deployed in the safe bastion modes, such a compromise is considered unacceptable in the case of SSNs where high speed manoeuverability and frequent need for power surges is intrinsic to its mission profile. Any such compromise in performance criteria could mean the difference between success and failure of the mission.

Further, in view of the enhanced projected holding of SSBNs and SSNs likely to be in service, there is a need for the IN to relook at the inventory of enriched fuel for the PWRs in service and to enforce accountability, take charge of the inventory control mechanism giving due consideration to the lifetime requirements and war reserves. Corporate responsibility for technological management of the propulsion system including HRD, should rationally be that of COM and DME. They are the competent authority and professional institutions responsible for the induction in the first instance.


  1. Bharat Karnad – “Nuclear weapon & Indian Security” p. 646: Vivek Preladan on 22 Nov 2016 in the Daily Order refers to CNS and quotes PN Haksar’s articulation of a nuclear triad in 1968.
  2. Ibid, p. 646.
  3. Revi, Indian Defence Review, Vol 27(3) Apr-Jul 2012 p. 53.
  4. Avtar Singh Bhasin, India & Pakistan – neighbors at odd. 2018.
  5. Yogesh Joshi, National archives 24 Apr 1970, PM secretariat File No 56/69/70 – parl.
  6. Yogesh. Doc 13.
  7. Yogesh Samudra, India’s convoluted path to undersea nuclear weapon 2019 ref 43.
  8. Yogesh, Ibid ref: 45; Revi, Indian Defence Review, Vol 31(1) Jan-Mar 2016, p. 84; Indian Defence Review, Vol 32(2) Apr-Jun 2016, p. 17.
  9. Yogesh, Ibid
  10. Bharat Karnad, Ibid
  11. Raj Chengappa – Weapons of peace, p. 228. Ibid, Bharat Karnad argues that much before the draft nuclear doctrine was released in 1999, India had embarked on a “triadic deterrent structure planned 20-30 years earlier,” p. 305.
  12. George Perkovich – India’s bomb: The impact on global nuclear proliferation
  13. Yogesh, NPIHP W6 2015.
  14. Ibid, Doc 2 p. 46.
  15. Vivek Praladan – on 22 Nov 2016 in Daily O refers to a CNS and quotes PN Haksar’s articulation of a nuclear triad in 1968.
  16. General KV Krishna Rao, In the Service of the Nation: Reminiscences, (New Delhi: Viking, 2001), p. 234.
  17. Karnad, Ibid, pp. 648-49; Revi8, Ibid, Jan 2016, p. 84.
  18. Parliament debate: RS Part I – 06 Dec 1983; pp. 11-12.
  19. Yogesh Samudra p. 17; Inder Malhotra: IDSA 12 Oct. 2012 – Nuclear proliferation International Seminar Project.
  20. Revi, Indian Defence Review,8 Mar 2016 p. 84.
  21. Sanyal Surjith Second Strike Para 59.
  22. Press Trust of India, 27 April 1998; SIPRI Yearbook 2002, p. 561; Revi8 p. 84.
  23. Revi,8 Ibid, p. 83.
  24. Revi,8 Ibid, p. 85.
  25. Yogesh 14. Ref 4 & 5.
  26. Revi,8 Ibid, p. 88.
  28. Unnithan India today A peep into India’s top secret ….. nuclear s/m.
  29. Revi, Indian Defence Review, Vol 29(4) Oct-Dec 2014, p. 118.
  30. Karnad Ibid, p. 695 [% p. 38] French offered a package deal – s/m stealth technology & technology for cool launch of SLBM from submerged state using compressed air.
  31. Revi, Indian Defence Review, Vol 27(3) Jul-Sep 2012, p. 55.
  32. Karnad, p. 651.
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