다음은 지난 9~13일 북한을 방문해 2000개의 원심분리기를 갖춘 우라늄 농축 시설의 존재를 확인하고 돌아온 지그프리드 헤커 미 스탠퍼드대 국제안보협력센터 소장의 방북 보고서 중 주요 내용이다.
헤커 박사는 이 보고서에서 "우리는 북한이 영변에서 플루토늄 생산을 재개했다는 어떤 증거도 찾을 수 없었다"며 "우라늄 농축 시설은 핵무기 개발이 아닌 민간 전력 생산을 위한 것처럼 보였다"고 말했다.
만약 북한이 핵무기 개발을 의도했다면 우라늄 농축 시설을 짓는 것보다 이미 보유 중인 흑연로 원자로를 재가동하거나 더 큰 규모의 흑연로를 짓는 것이 더 쉽고 빠른 길이라는 설명이다.그러나 헤커 박사는 우라늄농축시설이 핵무기 개발에 전용될 가능성을 우려하면서 이를 막기 위해서는 전쟁이나 대북제재 강화가 아니라 북한과의 협상에 의해 문제를 풀어야 한다고 강조했다.
다음은 이 보고서의 주요 내용이다. (☞ 보고서 전체 원문보기) <편집자>
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요약
스탠퍼드대학교 동료인 존 루이스 교수와 로버트 칼린 연구원과 함께 12일 영변 핵시설을 방문했을 때 25~30 메가와트(MW)급의 경수로 시설이 건설 중인 것을 보았다. 이것은 북한이 경수로를 건설하려는 최초의 시도이다. 북한 관계자들은 이 시설이 고유 기술과 자원으로 지어지고 있으며 2012년 완공을 목표로 하고 있다고 말했으나 그 전망은 지나치게 낙관적으로 보였다.
핵연료 생산시설에서 우리는 현대적인 시설로 안내되었는데 최근 완공된 그곳에는 2000개의 원심분리기를 갖춘 상당 규모의 우라늄 농축 시설이 있었다. 북한 관계자들은 이 시설에서 새로 짓고 있는 (경수로)발전소에서 사용할 핵연료인 저농축 우라늄(LEU)을 생산한다고 말했다. 이전에 방문한 영변의 다른 핵시설과는 달리 우라늄 농축 설비는 초현대적이었고 깔끔했다. 그들은 또한 이 시설 역시 순수한 북한 고유의 기술과 자원으로 건설됐고 운영되고 있다고 말했다.
이 시설들은 민간 핵발전을 위해 설계된 것처럼 보였고 북한의 군사적 핵능력을 강화하기 위한 것처럼 보이지는 않았다. 군사적 핵능력은 (우라늄 농축 시설을 새로 짓기보다는) 가동 중단된 5MWe 급의 흑연로를 재가동하거나, 더 큰 규모의 흑연로를 짓거나, 추가 핵실험을 함으로써 더 신속히 강화될 수 있기 때문이다. 그러나 우리는 북한이 영변에서 플루토늄 생산을 재개했다는 어떤 증거도 찾을 수 없었다. 그럼에도 불구하고 우라늄 농축 설비는 핵무기 생산이 가능한 고농축 우라늄(HEU) 생산으로 전용(轉用)될 수 있고 다른 곳에 추가 시설이 존재할 수도 있으며, 경수로는 폭탄 생산에 적합한 플루토늄 생산을 위해 가동될 수 있다. 하지만 경수로는 북한이 이미 보유한 원자로보다 핵무기 생산에는 훨씬 부적당하다.
이번 방문에서 우리는 북한 핵 정책의 방향에 대한 몇 가지 해답을 얻을 수 있었다. 하지만 이보다 더 많은 의문을 갖고 돌아왔다. 미국과 동맹국들이 이런 핵개발에 대해 어떻게 반응을 해야 북한이 핵무기에 더욱 의존적하기보다는 그들이 경제적 상징적 이유로 간절히 원하는 평화적 원자력 전력 생산으로 방향을 틀게 만들수 있는 것일까?
"우라늄 농축 워크숍"이라고 불리는 북한의 우라늄 농축 설비
연료 생산 설비에서 우리는 우라늄 산화물 생산 건물을 지나 약 100미터 높이의 새로 지어진 것처럼 보이는 건물로 들어갔다. 우리는 후에 그 건물이 지난 2008년 2월 핵시설 불능화를 검증하기 위해 방북했을 때는 금속 핵연료봉을 생산했던 건물이었다는 것을 깨달았다. 우리는 반들반들 윤을 내어 닦은 화강암 계단을 지나 2층의 통제실로 들어갔다. 유리창을 통해 처음 보인 것은 기겁할 만하게 놀라운(stunning) 광경이었다. 북한에 존재할 거라고 믿은 작은 원심분리기 시설 대신 우리는 1000대도 넘는 현대적이고 깨끗한 원심분리기 설비를 보았다. 그 원심분리기들은 비스듬히 줄맞춰 세워져 있었다.
시설 중앙부의 양 측면에는 각각 하나씩의 높은 구역이 있었다. 이 구역은 2층 빌딩 정도의 높이였고 북한 관계자들은 50m 길이라고 말했다. 이 구역의 폭은 12~15m 정도로 보였다. 원심분리기들은 세 줄로 줄맞춰져 좁은 공간을 두고 한 쌍으로 늘어서 있었고 양쪽 벽 끝까지 이어져 있었다. 그들은 우리에게 2009년 4월 이 시설을 짓기 시작해 불과 며칠 전 완성했다고 말했다. 우리 머리 위로는 120m 길이의 푸른 지붕이 펼쳐져 있었다.
원심분리기는 지름이 약 20cm, 높이가 1.82미터 정도로 추산됐다. 그 기계들은 매끄러운 알루미늄으로 둘러싸인 것처럼 보였고 냉각 코일은 보이지 않았다. 이 시설의 수석 엔지니어는 우리에게 이 시설에는 2000개의 원심분리기가 6개의 라인으로 설치돼 있다고 말했다. 양쪽에 1000개의 원심분리기가 3개의 라인으로 설치됐다고 그는 덧붙였다. 그는 기계의 구체적인 치수에 대해서는 언급하지 않았다. 미국도 그런 구체적인 정보는 공개하지 않고 있다고 그는 말했다. 하지만 우리가 그 원심분리기가 P-1모델(구형 파키스탄 모델)이냐고 묻자 그는 아니라고 답했다. 우리가 계속 묻자 그는 그 장치는 철 합금으로 돼 있다고 말했다.
계속된 질문에 대한 응답으로 그 엔지니어는 이 장비는 하나의 송풍구를 갖고 있으며 외부 케이스는 알루미늄 합금으로 제작됐다고 말했다. 그는 모든 기계의 모든 부분은 북한 국내에서 제작됐다고 주장했으나 네덜란드의 알멜로나 일본의 로카쇼무라의 모델을 본따 만들었다고 말했다. 우리는 가장 중요한 세부 정보를 얻어낼 수 있었는데 그것은 우라늄 농측 능력에 관한 것이었다. 그는 1년에 8000kg 분리 작업 단위(SWU : Sepreating Work Unit)의 우라늄을 처리할 수 있으며 평균 농축 수준은 3.5%라고 말했다. 원자로 설계 담당자는 그에게 목표치는 2.2~4%라고 말해 주었다.
수석 엔지니어는 처음에는 우리에게 이 시설을 공개하지 않을 생각이었으나 상부에서 공개를 지시했다고 말했다. 결과적으로 그들은 우리에게 최소한의 부분만을 공개했고 어떤 정보도 자발적으로 제공하지 않았으며 가능한 빨리 우리의 방문 일정을 끝내려 했다.
통제실은 놀랍도록 현대적이었다. 1950년대 미국이나 1980년대 소련의 시설처럼 보였던 (플루토늄)재처리 시설이나 원자로 통제실과는 달리 현대 미국의 처리 시설과 비슷했다. 통제실에는 작동 중인 설비의 변동 상태를 표시하는 LED 출력 장치가 달린 다섯 개의 큰 상황판이 갖춰져 있었고 컴퓨터와 네 대의 평면 모니터가 있었다. 이 모니터는 평양의 김일성대학에서 본 것과 유사했다. 모니터에는 도표와 많은 숫자들이 표시돼 있었으나 관계자들은 우리가 그 내용을 알아보거나 질문을 할 수 없을 정도로 빠르게 그 곳을 지나가도록 했다.
그리고 우리는 추출실로 들어갔는데 그 곳에는 두 대의 교환 장비와 두 대의 상황판, 많은 탱크와 배관들이 있었다. 지상 1층으로 내려가는 계단도 있었고 직류 전원이 연결된 두 개의 철제 계기판과 작은 탱크 뒤에 큰 탱크가 있었다. 우리가 자세히 보지는 못했지만 직경은 1m, 길이는 2m 정도였으며 수평으로 설치돼 있었다.
관계자들은 우리를 최대한 빨리 건물 밖으로 이끌고 싶어했지만 우리는 질문을 계속했다. 나는 그들이 2000개의 원심분리기 설비를 그렇게 빨리 갖춘 데 대해 놀라움을 표시하며 현재 이 시설이 작동 중인지를 다시 한 번 물었다. 그 엔지니어는 '그렇다'고 강조했다. 우리가 육안으로 관찰하는 것만으로는 이 설명이 맞는 것인지 독립적으로 확인할 수는 없었다.
우리는 그 설비가 북한의 자체 기술로 지어진 것이라는 그들의 주장을 검증해 보았다. 예를 들어 설비를 짓기 위한 적절한 장치를 보유하고 있는지, 베어링은 어떤 것을 사용했는지 등을 물어 보았다. 하지만 구체적인 답은 듣지 못했다. 그 엔지니어는 그들이 가스 원심분리기에서 사용하기 위해 '6불화 우라늄'을 생산한다고 말했으나 과거 북한은 이 물질을 생산 중이라는 것을 인정하지 않았다. 그들은 원심분리기 설비에서 이용할 만큼 충분한 양을 처리하고 있다고 말했다.
다른 관계자는 나의 질문에 답하며 '지금 우라늄을 농축하고 있다'고 확인해 주었다. 내가 국제사회는 이 시설이 고농축 우라늄(HEU)을 생산하는 용도로 전용될까봐 우려할 것이라는 점을 지적하자 그 관계자는 '통제실의 모니터를 보면 누구나 (HEU가 아닌) 저농축 우라늄(LEU)을 생산하고 있음을 알 수 있을 것'이라고 말하며 '그들(국제사회)은 하고 싶은 대로 생각할 수 있다'고 덧붙였다.
토론
이번 발견은 북한의 핵개발 방향에 대한 많은 질문에 답을 주었지만 그만큼 혹은 그 이상의 의문을 더 불러일으켰다. 기초적인 분석은 이렇다. 플루토늄 프로그램은 동결됐고 오히려 퇴보한 것으로도 볼 수 있다. 그들은 금속 연료봉 생산 설비를 원심분리기 설비로 교체했고 이는 플루토늄 생산을 더 어렵게 하는 것이다.
경수로를 통해 플루토늄을 생산할 수 있지만 5MWe급 반응로(흑연로)보다 핵폭탄 생산에는 더 부적절하다. 게다가 경수로에서 사용한 핵연료봉을 재처리하기 위해서는 북한이 보유한 (흑연로에 맞게 설계된) 재처리 시설을 (경수로에 맞게) 변형시켜야 한다. 5MWe 흑연로를 통한 북한의 핵무기 생산능력에 대해 나는 이전에 24~42kg이라고 분석한 적이 있다. 이는 4~8개의 기초적 수준의 핵폭탄을 생산하기에 충분한 양이다. 이는 지금도 유효한 분석이다.
북한이 우라늄 농축 프로그램을 갖고 있다는 의혹은 오래 전부터 있어왔다. 나는 북한이 이 프로그램을 이미 1970~1980년대부터 시작했다고 생각하지만 1990년대에 파키스탄의 핵과학자인 A.Q.칸과 거래하기 전까지는 이 프로그램을 본격화하지는 않은 것으로 판단했다. 하지만 (이번 방문에서 확인한) 2000개의 원심분리기를 갖춘 설비는 나와 대다수 분석가들의 예측을 뛰어넘는 것이었다. 우리는 그 설비들이 완전히 가동되는지는 확인할 수 없었다. 보통 그 정도 규모의 설비를 완공하고 완전히 가동시키기 위해서는 더 많은 시간이 필요하다. 그럼에도 불구하고 북한의 주장이 사실이라면 그들은 연간 2t의 LEU를 생산할 수 있을 것이며 만약 HEU 생산으로 전환한다면 1년에 40kg의 HEU를 생산할 수 있을 것이다. LEU 생산능력(2t/년)은 그들이 현재 건설 중인 경수로 발전소가 소모하는 연료 양과 일치한다. 만약 언젠가 북한이 더 큰 규모의 경수로 발전소를 짓는다면 핵연료 생산량도 늘어날 것이다.
북한이 생산하는 것이 LEU인지 HEU인지는 시설 내의 모니터를 통해 쉽게 파악할 수 있는 것으로 보인다. 하지만 가장 우려되는 것은 이 시설과 유사하거나 더 큰 규모를 갖춘 시설이 어딘가에서 HEU를 생산할 가능성이다. 그런 시설이 존재한다 해도 탐지하기 어렵다는 것은 이번에 확인된 시설도 북한이 공개하기 전까지는 알 수 없었다는 것을 보면 알 수 있다. 심지어 이번에 공개된 시설은 영변 한복판에 있었는데 말이다.
북한의 핵능력을 제한할 유일한 요소는 필요한 자재나 장비를 조달하거나 생산할 능력이다. 특수 처리된 강철이나, 고강도의 알루미늄관, 고리모양 자석 같은 것들 말이다. 우리는 이런 물품들을 생산하기 위해 북한이 어느 정도의 기술을 보유했는지 아는 바가 거의 없다. 만약 북한이 자신들의 우라늄 프로그램이 평화적 목적이라고 주장한다면 그 주장을 스스로가 입증할해야 하는부담을 지게 될 것이다(IAEA의 핵사찰을 받아야 하는 등). 북한은 지난 6자회담 기간 동안 이에 대해 계속 부정해 왔다.
가장 알기 어려운 문제는 북한이 어떻게 이 시설을 지었냐는 것이다. 핵군축 싱크탱크인 과학국제안보연구소(ISIS)의 데이비드 올브라이트 소장과 폴 브레넌 수석연구원은 최근 북한의 우라늄 농축 프로그램의 현황을 분석한 바 있다. 이들은 북한이 파키스탄의 칸 연구소에 기술자를 보내는 등 파키스탄과 기술 교환 및 협력을 진행시킨 것 같다고 주장했다. 나는 이전에 북한과 이란이 핵개발에 협력할 가능성을 우려한 바 있다. 하지만 지금은 더 상세한 분석과 재평가가 이루어져야 할 때이다. 상황을 잘 이해해야 북한의 우라늄 농축 능력 현황과 계획에 대해 더 잘 판단할 수 있기 때문이다.
북한의 의도를 파악하는 것은 더욱 어렵다. 이전에 나는 당초 (체제) 안전보장이라는 목적에서 시작된 핵무기 개발은 국내외적으로 어떤 문제를 초래하는가를 분석한 바 있다. 북한은 미국이 적대정책을 계속하는 한 자신들도 하겠다고 핵무기를 보유하겠다고 분명히 말했다. 내가 이번 방북에서 만난 북한 당국자들도 북미관계의 근본적인 변화 없이는 비핵화는 없다고 여러 차례 말했다.
나는 또한 북한이 진정으로 핵개발을 통해 전력 생산을 할 가능성에 대해서도 생각해 보았다. 이는 실용적인 면에서나 상징적인 면에서 의미가 있다. 북한은 경수로가 핵개발에서 더 현대적인 방법이라고 생각하고 있다. 과거 북한은 여러 차례 자신들이 핵(무기 개발)을 포기하는 대신 경수로를 달라고 요구해 왔다. 이번에 우리가 들은 북한의 메시지는 '됐고! 더 이상 기대 안 한다, 우리 손으로 직접 만들겠다'는 것이다. 그들은 우리에게 지난 4월 그들이 스스로 경수로 발전소를 건설하려 했던 것을 상기시키며 "헤커 박사, 당신을 포함해서 아무도 우리를 믿지 않았소"라고 말했다. 그들은 경수로 발전소에서 필수적이라는 것을 근거로 우라늄 농축 시설 보유가 정당하다고 주장할 수도 있다.
그럼에도 나는 이 핵의 평화적 이용 프로그램이 군사적인 것으로 전환될 수도 있다고 생각한다. 북한 정권은 그들이 보유한 몇 개의 플루토늄탄만으로도 이미 적지 않은 정치적 부담을 졌고 미사일에 탑재하기에는 플루토늄탄이 HEU보다 유리하지만 많은 양의 HEU를 생산해 추가로 핵실험을 한다면 그들의 핵군사력은 더 강화될 것이다. 더욱 우려스러운 것은 물질이나 핵 관련 기술을 수출할 가능성이다. 이런 이유로 미국과 북한은 지금처럼 가만히 앉아 있어서는 안 된다.
무엇을 해야 하는가
수많은 물음이 우리 앞에 놓여 있다. 북한은 진정 핵을 이용한 전력 생산을 추구하고 있는가? 만약 그렇다면 외부의 도움 없이 성공할 기회는 무엇인가? 북한은 플루토늄 생산 시설을 포기하거나 동결시킨 상태로 유지할 것인가? HEU를 생산할 수 있는 원심분리기 설비는 추가로 존재하는가? 어떻게 북한은 이렇게 복잡한 수준의 설비를 갖출 수 있었나? 왜 북한은 이 설비를 우리에게 공개하기로 결정했나? 이번 공개 결정이 그들의 전략의 일부인가?
이런 질문들에 대한 답이 나오려면 좀더 많은 시간과 연구인력이 필요하다. 하지만 최소한 하나는 확실하다. 이번 공개조치가 국제정치에서 대격변을 불러올 것이라는 점이다. 어떤 사람들은 '역시 북한은 믿을 수 없다'며 이번 공개조치를 이용할 것이고 어떤 사람들은 2002년 미국이 우라늄 농축 의혹을 제기하며 제네바합의의 이행을 중지한 것을 정당화할 것이다. 중국이나 러시아 같은 국가들은 북한이 핵에너지를 개발할 권리가 있는 주권국임을 주장할 것이다. 이 문제는 원래 핵에너지 자체가 (평화적 이용과 군사적 이용이라는) 양면성을 띠기 때문에 매우 복잡하다.
북한의 우라늄 시설은 기본적으로는 북한의 전력 수요를 충당하기 위해 지어진 것으로 보인다. 하지만 군사적 목적으로 전용될 가능성이 있기 때문에 무척 심각한 사태인 것도 맞다. 6자회담을 통한 합의만이 문제를 해결할 수 있다는 것은 명백하며 군사적 공격은 말도 안 되는 소리다.
마찬가지로 북한에 대한 제재 조치 강화도 별 쓸모가 없다는 것이 드러났다. 특히 (이번 방문에서 그동안의 제재조치에도 불구하고) 북한의 핵개발이 더욱 진전됐으며 평양의 경제적 상황은 오히려 개선된 것으로 확인된 점을 고려하면 더욱 그렇다. 유일한 희망은 협상을 통해 북한을 관리하는 것이다. 미국과 동맹국들은 북한의 이번 핵개발 성과에 반응을 보여 북한이 핵무기 대신 전력 생산으로 방향을 잡도록 유도해야 한다. 북한의 고위당국자는 우리에게 지난 2000년 매들린 올브라이트 당시 미 국무장관의 평양방문을 가져온 북미 공동 코뮤니케를 언급하며 이는 좋은 출발점이 될 것이라고 말했다.
/곽재훈 기자
A Return Trip to North Korea’s Yongbyon Nuclear Complex
Siegfried S. Hecker
Center for International Security and Cooperation, Stanford University
November 20, 2010
Summary
On November 12, during my most recent visit to the Yongbyon Nuclear Complex with Stanford University colleagues John W. Lewis and Robert Carlin, we were shown a 25 to 30 megawatt-electric (MWe) experimental light-water reactor (LWR) in the early stages of construction. It is North Korea’s first attempt at LWR technology and we were told it is proceeding with strictly indigenous resources and talent. The target date for operation was said to be 2012, which appears much too optimistic.
At the fuel fabrication site, we were taken to a new facility that contained a modern, small industrial-scale uranium enrichment facility with 2,000 centrifuges that was recently completed and said to be producing low enriched uranium (LEU) destined
for fuel for the new reactor. Unlike all previously visited Yongbyon nuclear facilities, the uranium enrichment facility was ultra-modern and clean. We were also told that this facility was constructed and operated strictly with indigenous resources and talent.
These facilities appear to be designed primarily for civilian nuclear power, not to boost North Korea’s military capability. That can be accomplished much more expeditiously by restarting the dormant 5 MWe gas-graphite reactor, constructing a new, larger gas-graphite reactor and conducting additional nuclear tests; but we saw no evidence of continued plutonium production at Yongbyon. Nevertheless, the uranium enrichment facilities could be readily converted to produce highly-enriched uranium (HEU) bomb fuel (or parallel facilities could exist elsewhere) and the LWR could be run in a mode to produce plutonium potentially suitable for bombs, but much less suitable
than that from their current reactor.
This visit allowed us to answer some questions about Pyongyang’s nuclear directions; but it also raised many more. How the United States and its partners respond to these developments may help to shape whether Pyongyang will rely more on the bomb or begin a shift toward nuclear electricity, which it wants both for economic and symbolic reasons.
Yongbyon Nuclear Scientific Research Center
This was my fourth trip to the Yongbyon nuclear complex. During my first visit in January 2004, they showed me a sample of plutonium metal that was reprocessed from the spent fuel rods that had been stored since 1994 as part of the Agreed Framework and subsequently used as bomb fuel for its nuclear test. During all six of my previous trips to North Korea, government officials and technical specialists denied the existence of any uranium enrichment activities. Following the 2009 rocket launch and second nuclear test, Pyongyang expelled the U.S. technical team and international inspectors and declared that it would build its own light-water reactor (LWR) and produce its own fuel. For this visit, I requested to see the key nuclear sites to judge their current status and to see the uranium enrichment technology that they announced in September 2009 to have been
2
successful.1 on Nov. 12, we were taken to Yongbyon and shown an LWR construction site and a uranium enrichment centrifuge facility.
At the new three-story Guest House, we were met by a small Yongbyon technical team and representatives of the General Bureau of Atomic Energy. The senior technical official gave the following introduction: “In the 1980s and 1990s, we agreed to give up our reactors for LWRs, 2,000 Megawatt-electric (MWe) by 2003. In the early 1990s we built 50 and 200 MWe reactors (of gas-graphite design). Now they have become ruined concrete structures and iron scrap. We have not been able to contribute to the national demand for electricity. So, we decided to make a new start. For us to survive, we decided to build our own LWR. on April 15, 2009, the Foreign Ministry stated that we will proceed with our own LWR fuel cycle. We have completed the discharge of the 5 MWe spent fuel, reprocessed it and delivered it to the military for weaponization.2 Our nuclear program has not proceeded as expected, we have not delivered electricity and that has impacted the economic condition of our country. We will use our economic resources to solve the electricity problem. We are willing to proceed with the Six-Party Talks and the September 19, 2005 agreement, but we cannot wait for a positive agreement. We are trying our best to solve our own problems. We will convert our center to an LWR and pilot enrichment facility. It is a high priority to develop uranium enrichment. We will have some difficulties with this, but we are proceeding with the LWR fuel cycle. We have designated a site for the LWR and also for uranium enrichment – it is the first stage, so it is first priority. The construction is completed and the facility is operational. You will be the first to see this facility. We showed the LWR construction site to the Korea Economic Institute delegation (Charles L. Pritchard and colleagues).”3 Our hosts had initially targeted our visit to the complex to last 3.5 hours, including lunch. Unlike in my previous visits to Yongbyon, the technical team clearly had instructions to show us only the basics at two facilities and answer a minimum of questions. We were hurried along at every stage. We eventually spent 3.5 hours at the site before lunch.
Experimental 25 to 30 MWe LWR construction
At the 5 MWe reactor site we were taken to a construction site that had been identified previously from overhead imagery.4 The chief engineer of the 5 MWe reactor showed us the site and answered questions, but only when pressed. The large excavated pit was roughly 40 meters by 50 meters by 7 meters deep. A concrete foundation 28 meters square with round concrete preforms for the reactor containment vessel was visible. The containment vessel was about one meter high at the time we saw it. We were told it will be 22 meters diameter, 0.9 meters thick and 40 meters high. It is designed for a power level of 100 MW (thermal). He chose not to specify the electrical power, but said
1 In a September 4, 2009 letter to the President of the UN Security Council, the North Korean permanent representative to the United Nations stated that North Korea’s “experimental uranium enrichment has successfully been conducted to enter into completion phase.” (Korean Central News Agency – KCNA).
2 A reference to North Korean action following the expulsion of the U.S. technical team and international inspectors.
3 This quote is based on our notes of the interpreter’s version of the technical official’s comments.
4 David Albright and Paul Brannan,
3
that the conversion efficiency is typically 30 percent. Therefore, I estimate the electrical power to be roughly 25 to 30 MWe.
This, of course, is much smaller than the two 1,000 MWe LWRs that were being constructed as part of the KEDO project at the Kumho site.5 They explained that the LWR design is different from their experience base of gas-graphite reactors; hence they are building this small prototype first. once they have mastered this technology, they will build a bigger LWR. However, even with the 25 to 30 MWe reactor, they will build two electrical generators that will supply electricity to the local communities and be hooked
into the national grid. The chief engineer said the construction was started on July 31,
2010. He said the target date for operations is 2012 (which is unreasonably optimistic, but
coincides with the centenary of Kim Il-sung’s birth and is the target date for most current
major projects). There were nearly 50 workers on the floor – all of them dressed in dark
blue coveralls and hard hats. We enquired about reactor safety analysis and practices.
They claimed to have excavated down to the bedrock and that they had performed
seismic analysis of the site.
The pressure vessel will be fabricated out of high-strength steel, possibly with a
stainless steel liner. The chief engineer said that they will be able to manufacture it
domestically. They will make all the pumps and other reactor components domestically
and have the requisite welding capabilities. In addition to the standard propaganda signs,
they displayed the following safety sign at the site: “Safety first – not one accident can
occur!” I asked if they have a nuclear regulatory agency. The chief engineer said that the
National Nuclear Safety Commission has oversight. They submitted their plans to the
Commission. They inspect the site. They have nuclear specialists at the Standing
Committee and have inspectors on the site.
The reactor will be fueled with uranium dioxide fuel enriched to 3.5%, typical of
LWR fuel, but very different from the metallic uranium alloy fuel rods used in the gasgraphite
reactor. A full load of fuel is comprised of four tonnes of uranium. In a separate
discussion, they reiterated that they had ample domestic uranium ore resources. They
were not certain what cladding material would be used, stating that they are still working
on many of the details. The reactor design team is a new, young team without reactor
design experience. However, they assured us that they would be mentored by the
experienced gas-graphite reactor designers. The new designers are in their 40s, graduated
from North Korean universities and have spent their careers at Yongbyon. They have not
brought any of the North Korean KEDO LWR team members to Yongbyon at this time,
but may do so for the operational phase.
Uranium enrichment facility – called the “Uranium Enrichment Workshop”
5 The Korean Peninsula Energy Development Organization (KEDO) project was to have the United States
and other parties build two 1,000 MWe LWRs for North Korea at the Kumho site. It was established in
March 1995 as part of the Agreed Framework. The LWR project was terminated in 2006.
http://www.nti.org/e_research/official_docs/inventory/pdfs/kedo.pdf
4
At the fuel fabrication plant we entered what appeared to be a new building about
100 meters long, across from the tall uranium oxide production building. We later
identified it as the former metal fuel rod fabrication building, which I had visited in Feb.
2008 to verify their disablement actions. We walked up polished granite steps to the
second-floor control room and observation area. The first look through the windows of
the observation deck into the two long high-bay areas was stunning. Instead of seeing a
few small cascades of centrifuges, which I believed to exist in North Korea, we saw a
modern, clean centrifuge plant of more than a thousand centrifuges all neatly aligned and
plumbed below us. There were two high-bay areas on each side of the central island. The
high-bay areas were two stories high and we were told 50 meters long each. We
estimated the width of the bays to be 12 to 15 meters. There were three lines of centrifuge
pairs, closely spaced, the entire length of each hall. We were told that they began
construction in April 2009 and completed the operations a few days ago. Overhead
imagery now shows a building with a blue roof about 120 meters long.
We estimated the centrifuges to be about 8 inches (20 cm) in diameter and
approximately 6 feet (1.82 meters) high. They looked like smooth aluminum casings (no
cooling coils visible) with three small stainless steel tubes emanating from the top to the
central plumbing that ran the length of the facility. The highest horizontal line appeared
to be an insulated pipe about 10 cm diameter. The chief process engineer told us (in
response to persistent questioning6) that the facility contained 2,000 centrifuges in six
cascades (one thousand centrifuges and three cascades on each side). He would not
provide us with the physical dimensions, stating that the United States would also not
release such proprietary information. When asked if they were P-1 centrifuges,7 he said
no. When pressed, he said the rotors were made of alloys containing iron.8 In response a
subsequent question, the chief process engineer implied that the rotors had single bellows.
The casings, he said, were made from an aluminum alloy. He claimed all components
were manufactured domestically, but modeled after the centrifuges at Almelo and
Rokkasho-mura. 9 We were able to extract the most important detail, that is, the
enrichment capacity, which he said was 8,000 kg SWU/year.10 The average enrichment
level is 3.5% and the tails are 0.27%. The reactor designers told him to target enrichment
levels from 2.2 to 4%.
The control room was astonishingly modern. Unlike the reprocessing facility and
reactor control room, which looked like 1950s U.S. or 1980s Soviet instrumentation, this
6 The chief process engineer told us at the outset that they did not want to show us this facility, but their
superiors told them to do so. Consequently, they showed us as little as possible, did not volunteer any
information, and hurried us along as much as possible.
7 The P-1 designation refers to the Pakistani design copied from the least advanced URENCO centrifuges.
These contain high-strength aluminum alloy rotors and high-strength aluminum alloy casings.
8 This most likely makes them P-2 centrifuges (which were based on the German G-2, that was developed
by the Germans as part of the URENCO consortium), which typically have high-strength maraging steel
rotors that can by spun much faster than the aluminum rotors, thereby increasing the throughput.
9 URENCO’s enrichment facilities are located in Almelo, Netherlands and Japanese Nuclear Fuels Limited
operates a uranium enrichment facility in Rokkasho-mura.
10 The kg SWU is an acronym for kg of separative work units. It refers to the amount of isotope separation
achieved (separating the fissile U-235 isotope from the non-fissile U-238 isotope).
5
control room would fit into any modern American processing facility. They had five large
panels in the back that had numerous LED displays of operating parameters. They had
computers and four flat-screen monitors (similar to ones we saw at the e-Library at Kim
Il-sung University in Pyongyang). The monitors had flow diagrams and lots of numbers
displayed, but they ushered my past so quickly that I was not able to tell what they
signified.
We went into the recovery room, in which we saw two operators, two flat screen
panels, and lots of tanks and plumbing. There was a set of steps leading down to the
ground floor. There were many small, galvanized steel panels and small tanks, and one
big tank in the back. We did not get a good look, but it may have been about one meter
diameter and two meters long, horizontally positioned. We were ushered outside as
quickly as possible, but continued to ask questions.
I expressed surprise that they were apparently able to get cascades of 2,000
centrifuges working so quickly, and asked again if the facility is actually operating now –
we were given an emphatic, yes. We were not able to independently verify this, although
it was not inconsistent with what we saw. We probed more deeply into their claims of
indigenous fabrication. For example, do they have flow-form machines to make the rotors,
and what about the bearings? We received no concrete answers. He claimed that they
produce uranium hexafluoride, the feed material for gas centrifuges but which they had
never admitted having produced in the past.11 They said they have sufficient throughput
for the size of the centrifuge facility.
I asked again about the fuel – will it be UO2 and how will they make it? He said
the process for learning how to make UO2 had begun. It is difficult and we will have
problems. We cannot get help from the outside, so we have to do it by ourselves. So, he
said, we will get started now. Before being whisked away back to the Guest House for a
late lunch and departure, in response to my question, the senior Yongbyon official
confirmed that they are enriching uranium now in the facility. When I pointed out that the
outside world will be concerned about their ability to convert the facility to make HEU,
he stated that anyone can tell by looking at the monitors in the control room that the
cascades are configured for LEU. Besides, he said, they can think what they want.
Update on status of existing plutonium production facilities
Although we were not specifically taken to the plutonium production facilities,
the facilities that we visited were located in the same areas. The 5 MWe reactor, which is
adjacent to the new LWR construction site, appeared dormant. There were at least two
long barrack-style buildings between the new construction site and the river. We were
told that the 5 MWe reactor is in stand-by status with regular maintenance. We were
reminded that the cooling tower was destroyed (June 2008) but the chief engineer was
confident that they could the reactor should they decide to do so (my previous estimate
11 In spite of prior North Korean denial, the nuclear materials recovered in Libya in 2003 when Col Gadaffi
relinquished his nuclear weapons program were reputed to include a shipment of uranium hexafluoride
from North Korea.
6
was that it would require approximately six months to do so). We were told the fresh fuel,
which could be used to refuel the reactor, was still stored in the same warehouse in which
I last saw it in 2008 (at the fuel fabrication facility). I was told that there was insufficient
time to visit the warehouse.
The 50 MWe reactor, which was near completion in the mid-1990s but abandoned
during the Agreed Framework was being dismantled with large cranes. It looked just like
the senior Yongbyon technical official described it: “a ruined concrete structures and iron
scrap.” No activity was apparent at the reprocessing facility as we drove past it. There are
several new buildings at the fuel fabrication site, including the one containing the
centrifuge cascade halls. That building was previously designated as Building 4, which
housed the uranium metal fuel rod fabrication. Its interior was completely reconstructed
and its exterior appeared freshly renovated.
To summarize the status of the plutonium facilities; the 5 MWe reactor has not
been restarted since it was shut down in July 2007. The spent fuel rods were reprocessed
following North Korea’s termination of the Six-Party talks in April 2009. No new fuel
has been produced and the fresh fuel produced prior to 1994 (sufficient for one more
reactor core) is still in storage. Pyongyang, has apparently decided not to make more
plutonium or plutonium bombs for now. My assessment is that they could resume all
plutonium operations within approximately six months and make one bomb’s worth of
plutonium per year for some time to come.
Discussion
The findings from this trip answer many questions about the North’s nuclear
directions, but they also raise at least as many. I will give a preliminary analysis here.
Clearly much more will have to be done by many more analysts to understand the
implications of these developments in North Korea.
The plutonium program remains frozen, and has perhaps even taken another step
backward. They converted the metal fuel rod fabrication facility into the centrifuge
cascade halls, thereby making it more difficult to make fuel for the plutonium production
reactor. The LWR will produce plutonium, but it is much less suitable for bombs than
that from the 5 MWe reactor. In addition, the reprocessing facility operations would have
to be reconfigured to reprocess the LWR fuel. My previous estimate of the North Korean
plutonium inventory from its 5 MWe reactor of 24 to 42 kilograms (sufficient for four to
eight primitive nuclear weapons) still stands.12
A North Korean uranium enrichment program has long been suspected. I believe
they started early, perhaps in the 1970s or 1980s, but then did not try to accelerate the
effort until their dealings with A.Q. Khan in the 1990s. However, the 2,000-centrifuge
12 Siegfried S. Hecker, “Lessons learned from the North Korean nuclear crises,” Daedalus, Winter 2010, pp.
44-56.
7
capability significantly exceeds my estimates and that of most other analysts.13 We were
not able to confirm that the facility is fully operational. It typically requires much more
time to bring cascades of this size into full operation.14 Nevertheless, they have either
done it as they claim, or are most likely capable of doing so shortly. With the 8,000 kg-
SWU/yr capacity, North Korea could produce up to 2 tonnes of LEU or, if the cascades
are reconfigured, up to 40 kg HEU. The LEU capacity is consistent with the requirements
of the LWR under construction. It would have to be expanded significantly if North
Korea eventually builds a large LWR. Whether LEU or HEU is produced in the facility is
easy to monitor with on-site presence or on-site instrumentation. However, the greatest
concern is that a facility of equal or greater capacity, configured to produce HEU exists
somewhere else. Such a facility would be difficult to detect as demonstrated by the fact
that this facility was undetected in the middle of the Yongbyon fuel fabrication site. The
only factors that would limit North Korea’s ability to build more are the procurement or
production of many of the specialty materials and pieces of equipment – such as
maraging steel, high-strength aluminum alloys, ring magnets, frequency converters,
special bearings, vacuum equipment, flow meters, etc. We have little knowledge of what
the North’s indigenous fabrication capabilities are. If North Korea claims its uranium
program is strictly peaceful, then the burden of proof is on it, especially since they
continued to deny it during the Six-Party negotiations.
One of the most puzzling issues is how they got this far? Albright and Brannan13
recently presented a detailed analysis of the status of North Korea’s uranium enrichment
program. They demonstrate a clear pattern of cooperation and exchange with Pakistan,
including crucial elements such as on-site training of North Korean technical specialists
at the Khan Research Laboratory. They also show troubling procurement scheme,
particularly with commercial entities in China. I have previously stated my concern about
potential cooperation and exchanges in uranium technologies between North Korea and
Iran. However, a detailed analysis and reevaluation taking into account the findings from
this trip is now in order. A better understanding is important because it will help us better
judge the capacity of current and planned North Korean enrichment capacity.
Understanding North Korea’s motivation is even more difficult. In the Daedalus
essay,12 I showed how an initially security-driven motivation for the bomb took on
important domestic and international dimensions. Pyongyang has clearly stated that it
will retain its nuclear weapons as a deterrent so long as U.S. hostile policies persist.
North Korean officials with whom we met on this trip made it abundantly clear that there
will be no denuclearization without a fundamental change in U.S. – North Korean
relations. In the Daedalus article and a subsequent article,15 I make the case that
Pyongyang has seriously pursued nuclear electricity; it has both practical and symbolic
importance. It views LWRs as the modern path to nuclear power. It was prepared several
13 For example, see Hui Zhang, “Assessing North Korea’s uranium enrichment capabilities,” Bulletin of the
Atomic Scientists, 18 June 2009 and David Albright and Paul Brannan, “Taking Stock: North Korea’s
Uranium Enrichment Program,” http://isis-online.org/uploads/isis-reports/documents/ISIS_DPRK_UEP.pdf
14 It took Iran about 20 years to procure, build and operate cascades of this size. Iran has roughly 8,000
centrifuges installed with 4,000 P-1s working for a total capacity of ~ 4,000 kg SWU.
15 Siegfried S. Hecker, Sean C. Lee and Chaim Braun, “North Korea’s Choice: Bombs over Electricity,”
The Bridge, Vol. 40, No. 10, Summer 2010, pp. 5-12.
8
times in the past to trade its bomb-fuel producing reactors for LWRs. This time we were
told, “We have given up; we will do it on our own.” We were reminded that in April
2009 they announced their intention to build an LWR and to make their own fuel,
including enrichment. They said, “no one believed us, including you, Dr. Hecker.” They
can claim with some justification that the uranium enrichment program is an integral step
toward an LWR and nuclear electricity.
I believe that although this peaceful program can be diverted to military ends, the
current revelations do not fundamentally change the security calculus of the United States
or its allies at this time. Pyongyang has gained significant political leverage already from
the few plutonium bombs they have. Building more sophisticated bombs that can be
mounted on a missile is better done with plutonium than HEU. However the production
of large quantities of HEU and additional nuclear tests would allow them to increase the
size of their arsenal. Even more troubling would be the potential of export of fissile
materials or the means of producing them, which now include centrifuge technologies.
For these reasons, the United States and North Korea should not sit by idle.
Where do we go from here?
Is Pyongyang really pursuing a modern nuclear electricity program? If so, what
are its chances of success without outside help? Has Pyongyang decided to abandon its
plutonium production complex (or at least keep it dormant)? Does it have additional
uranium centrifuge facilities that could easily be dedicated to producing HEU bomb fuel?
How did North Korea acquire centrifuge technology at such a level of sophistication and
when? Why did Pyongyang decide to show us the facilities now and how does this fit into
their broader strategy of how to deal with its domestic and international challenges?
These and other questions will take more time and more people to answer. one
thing is certain: these revelations will cause a political firestorm. Some will use them to
prove that Pyongyang can’t be trusted. Some will use them to justify the October 2002
U.S. decision to confront Pyongyang about uranium enrichment, which terminated the
Agreed Framework. Some, most likely China and Russia, will claim that North Korea is
within its sovereign rights to develop nuclear energy. The issue is complicated by the
inherently dual-use nature of nuclear technology. It is possible that Pyonyang’s latest
moves are directed primarily at eventually generating much-needed electricity. Yet, the
military potential of uranium enrichment technology is serious. It is clear that waiting
patiently for Pyongyang to return to the Six-Party talks on terms acceptable to the United
States and its allies will exacerbate the problem. A military attack is out of the question.
Tightening sanctions further is likewise a dead end, particularly given the advances made
in their nuclear program and the economic improvements we saw in general in
Pyongyang. The only hope appears to be engagement. The United States and its partners
should respond to the latest nuclear developments so as to encourage Pyongyang to
finally pursue nuclear electricity in lieu of the bomb. That will require addressing North
Korea’s underlying insecurity. A high-level North Korean government official told us
that the October 2000 Joint Communiqué, which brought Secretary Madeleine Albright to Pyongyang, is a good place to start.