I
R Generation Group
August 3, 1978
TO: B.A. Karrasch,
Manager, Plant Integration
FROM: D.F. Hallman,
Manager, Plant Performance Services Section (1149)
SUBJECT: Operator Interruption
of High Pressure Injection(HPI)
References:
(1)
B.M. Dunn to J. Taylor, Operator Interruption of High PressureInjection,
9 February 1978
(2)
B.M. Dunn to J. Taylor, Operator Interruption of High Pressure Injection,
16 February 1978
References 1 and 2
(attached) recommend a change in Babcock and Wilcox's philosophy for HPI
system use during low-pressure transients.Basically,
they recommend leaving the HPI pumps on, once HPI has been indicated, until
it can be determined that the hot leg temperature is more than 50~F below
Tsat for the RCS pressure.
Nuclear Service believes
this mode can cause the RCS (including the pressurizer) to be solid.The
pressurizer reliefs will lift, with a water surge through the discharge
piping into the quench tank.
We believe the following
incidents should be evaluated:
If the pressurizer
goes solid with one or more HPI pumps continuing to operate, would there
be a pressure spike before the reliefs open which could cause damage to
the RCS? 2. What damage would the water surge through the relief valve
discharge piping and quench tank cause?
To date, Nuclear Service
has not notified our operating plants to change HPI policy consistent with
References 1 and 2 because of our above-stated questions.Yet,
the references suggest the possibility of uncovering the core if present
HPI policy is continued.We request
that Integration resolve the issue of how the HPI system should be used.We
are available to help as needed.
D.F. Hallman
cc: E.R.
Kane
J.D.
Phinney
B.W.
Street
B.M.
Dunn
J.F. Walters