World Association of Nuclear Operators 
Moscow Centre
WANO – MC
25 Ferganskaya st, Moscow, 109507, Russia
Phone. +7 495 376 15 87
Fax: +7 495 376 08 97
info@wanomc.ru	
REQUEST
to provide technical and organizational information
via WANO

1.	NPP/Organization: Tianwan NPP	
2.	Information request topic: 
Consultation on issues related to the boundary of Tightness Test for primary circuit on VVER units.	
3.	Information request objective: 
Collect information about boundary of Tightness Test for primary circuit on VVER units.	
4.	Problem description: 
According to the relevant operation procedures, the Tightness Test for primary circuit should be performed after the main equipments sealed during the each refueling on Tianwan Units 1-4, which to verify the primary circuit tightness. The design documents and FASR reviewed by us, it was found that the boundary(or range) of the Tightness Test was no specified, only the test pressure  was  provided. At present, the boundary of Tightness Test for primary circuit is set as the boundary of Strength Hydrostatic Test on Tianwan Units 1-4. According to our investigation on other types of units designed according to ASME and RCCM in China, the boundary of the Tightness Test is same to the boundary of normal operation (In other words, the boundary valve state during Tightness Test is same to the valve state during normal operation), whose main purpose is to verify the sealing of the boundary for normal operation, So the boundary (or range) of Tightness Test is more smaller than the Strength Hydrostatic Test.	
5.	Specific questions: 
1. On the design of VVER unit, is there a clear definition for the boundary of Tightness Test for primary circuit? If yes, how is it defined?
2. How about the boundary(or range) of Tightness Test for primary circuit on the VVER unit in Russia? Whether it is also the normal operation boundary of the unit?
3．In addition ,what is the relationship betweenThe Boundary of Tightness Test，The Boundary of the Strength Hydrostatic Test and the Boundary of the Pressure of Primary circuit for VVER	
6.	Organizations proposed for distribution of this request: 
All VVER plants	
7.	Department – request initiator: 
Technical support department	
8.	Contact details of the requester: 
Mr. Shi Chunfeng  email: shicf@cnnp.com.cn	
9.	Request date: 16/08/2021