Dr. Mike Weightman, Director, Office for Nuclear Regulation,21st March,2013

21st March,2013

Dr. Mike Weightman,
Director, Office for Nuclear Regulation,
Redgrave Court,
Merton Road,
Bootle, Merseyside. L20 7HS

Dear Dr. Weightman,

Sizewell B Reactor Pressure Vessel: Possibility of Cracks

In reply to your Mr. Colin Patchett’s letter of the 22rd February to mine of the 18th January:

My thanks to Mr. Patchett for enclosing with his letter a hard copy of the Belgian Federal Agency for Nuclear Control’s 63 page document entitled ‘Doel 3 and Tihange 2 reactor pressure vessels provisional evaluation report, dated 3rd Febuary 2013 (the FANC report).

I have carefully read, and re-read this document in its entirety, and, as a retired consulting engineer, am alarmed by what it says, since its conclusions reflect our concerns about the possibility of cracks in the Sizewell B RPV.

From the FANC report I note in particular:

‘Unlike the other components of a reactor uni! there is no provision in the design for the replacement of a reactor pressure vessel… and a major crack or fracture… could lead to a possible core meltdown (a “severe accident”)’ pages 9 & 10.

‘Some uncertainty still exists regarding the capability of in-service inspection techniques to properly detect and characterize all present flaws in reactor pressure vessels’- page 58.

Among the numerous requirements by FANC’the licensee shall demonstrate that no critical hydrogen flake type defects are expected in the non-inspectable areas’- page 59 – and – ‘The licensee shall perform a pressure load test of the reactor pressure vessels…to demonstrate that no unexpected condition is present’ -page 61.

The whole FANC report and, in particular, the above extracts,lead us to reiterate yet again that the precautionary principle demands that action be taken now, to ensure physically that the ‘B’ RPV is free from cracks, and not to wait until the Spring 2016 Periodic Safety Review. Why not at the next B outage – late April, this year?

Your urgent reply to this, our third request is now sought. ‘Better be safe than sorry’.

 

Charles Barnett

Chairman. Shut Down Sizewell Campaign