TO:  B.A. Karacsh, Manager, Plant Integration                    cc: E.R. Kane

J.D. Phinney

FROM:  D.F. Hallman, Manager,      B.W. Street

Plant Performance Services Section (2149)      B.M Dunn

                                                                                       J.F. Walters

CUST:                                                                         File No.

                                                                                    Or Ref.


SUBJ:  Operator Interruption of High Pressure Injection (HPI)


DATE: August 3, 1978


References:  (1) B.M. Dunn to J. Taylor, same subject, February 9, 1978

                     (2) B.M. Dunn to J. Taylor, same subject, February 16, 1978


References 1 and 2 (attached) recommend a change in B&Ws philosophy for HPI system use during low pressure transients.  Basically, they recommend leaving the HPI pumps on, once the HPE has been initiated, until it can be determined that the hot leg temperature is more than 50 F below Tsat for the RCS pressure.


Nuclear Service believe this model can cause the RCS (including the pressurizer) to go solid.  The pressurizer reliefs will life, with a water surge through the discharge piping into the quench tank.


We believe the following incidents should be evaluated:


  1. 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 he relief valve discharge piping and quench tank cause?


To date, Nuclear Service has not notified our operating pants 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.


/s/ _____________________________________

D.F. Hallman