How operational is Yongbyon nuclear site?

Workers inside Yongbyon nuclear facility in 2008 by which time its five-megawatt reactor was inactive

Under Kim Jong-un, nuclear weapons development has been formally adopted as one of North Korea's top policy priorities, along with economic advancement.

Given the importance placed by the leader on demonstrating new achievements in the country's nuclear pursuits, it should come as no surprise that any external commentary questioning the technical sophistication of the country's nuclear and ballistic missile programmes is swiftly and harshly condemned by North Korean media.

On 8 September, satellite imagery analysis published by Johns Hopkins University examined recent activities at North Korea's Yongbyon nuclear complex and questioned the operational status of some of the facilities at the site.

Pyongyang lashed out. On 15 September it released a statement by the director of its Atomic Energy Institute insisting that all of its Yongbyon facilities had "started normal operations".

The statement appears to be carefully timed - and directed - rhetoric.

Doubts about status

In early April 2013, in the midst of a crisis on the Korean Peninsula over US-South Korean joint military exercises, North Korea announced it was "recalibrating" and "restarting" certain nuclear facilities at its Yongbyon complex "without delay".

All available analysis points to North Korea's sincerity in its stated aim, but it remains uncertain as to whether it has managed to restart the facility.

Yongbyon nuclear complex

• North Korea's main nuclear facility, believed to have manufactured material for previous nuclear tests

• Reactor shut down in July 2007 as part of a disarmament-for-aid deal

• International inspectors banned in April 2009 when North Korea pulled out of disarmament talks

• A uranium enrichment facility revealed in 2010

• In 2013, North Korea said it would restart the nuclear reactor

• Experts believe that reactor could make one bomb's worth of plutonium per year

Imagery analysis produced by experts since 2013 notes that characteristic signs of an operational reactor, including steam and hot water discharge, have not always been visible.

They have postulated that maintenance work could explain the intermittent inactivity.

However, these assessments rely upon very limited information - an unavoidable weakness when using open sources to analyse North Korea's nuclear development.

While satellite images may inject doubt about the operational status of the reactor at Yongbyon, they cannot be taken as conclusive proof of the North's dishonesty.

Weapons-grade uranium

Comparable uncertainties exist as to whether facilities relating to uranium enrichment at Yongbyon are operating normally.

The reactor once provided plutonium for Pyongyang's nuclear weapons programme

Both a uranium enrichment facility and an experimental light-water reactor were still under construction as of July 2015, though were rapidly nearing completion.

The former has been under development since 2009, and was initially said by North Korea to be designed to produce low-enriched uranium to fuel the planned experimental light water reactor, which would in turn allow for increased electricity generation in the country.

However, if the enrichment facility is recalibrated as implied by the April 2013 announcement, it would also be able to produce weapons-grade uranium.

One or both of these facilities may have been completed since the last satellite photos were made available in July, and it is therefore possible that they are operational as North Korea alleges.

Convey position of strength

True or not, North Korea's latest statement was not likely intended to reveal new insights into developments at Yongbyon, or settle the ongoing debate about the status of facilities there.

Pyongyang consistently boasts of the advanced stage of its nuclear and missile programmes regardless of the details, and it rarely acknowledges shortcomings in its most prized military programmes, even if such difficulties are actually encountered.

People in South Korea follow the announcements from North Korea with anxiety

Instead, North Korea is currently eager to remind observers of its intention to forge ahead with its nuclear and missile programmes regardless of the objections of the international community and especially its neighbours, including China.

It may also wish to heighten existing nervousness about the prospect of a forthcoming military provocation in order to convey a position of strength.

Tuesday's statement from the Atomic Energy Institute came within hours of another remarkably similar statement from the director of North Korea's National Aerospace and Defence Administration, outlining the achievements of the country's scientists and its intention to exercise its 'right' to launch satellites at a time of its choosing.

For months, South Korean, Japanese, and Western media have cited unnamed officials as saying that North Korea is readying itself to conduct a satellite launch in October, in time for the 70th anniversary of the founding of the Worker's Party of Korea.

Read together, these two statements will only cement fears that another provocation is on the cards.

Andrea Berger is a senior research fellow in nuclear analysis at the Royal United Services Institute. Follow her on Twitter @AndreaRBerger.