ML20150E145
| ML20150E145 | |
| Person / Time | |
|---|---|
| Site: | Seabrook  |
| Issue date: | 07/08/1988 |
| From: | George Thomas PUBLIC SERVICE CO. OF NEW HAMPSHIRE |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| IEB-88-004, IEB-88-4, NYN-88093, NUDOCS 8807150015 | |
| Download: ML20150E145 (4) | |
Text
- _.
0 G?orge S. Thomas V'ce President Nuclear Production NYN-88093 Put2c Service of New Hampshire July 8, 1988
- N,w Hampshiro Yankee Division United States Nuclear Regulatory Commission Washington, DC 20555 Attention:
Document Control Desk
References:
(a) Facility Operating License NPF-56, Docket No. 50-443 (b) NRC Bulletin 88-04, dated May 5, 1988, ' Potential Safety-Related Pump Loss"
Subject:
Response to NRC Bulletin 88-04 Dear Sir Ia response to R 'erence (b), this letter provides the results of analyses performed to date regarding the applicability or consequences of two design concerns affecting centrifugal pump minimum flow. The first design concern involves the potential for adverse interaction between two or more, safety-related, centrifugal pumps operating in a parallel configuration at minimum flow rates.
The second design concern involves the adequacy of centrifugal pump installed minimum flow capacity. All active, safety-related fluid systems at Seabrook Station have been revisied for the applicability of these two concerns.
In response to the first concern, each safety-related fluid system at Seabrook Station employing multiple centrifugsl pumps capable of operating in parallel was reviewed to determine whether or not the system design configuratior, precludes pump-to-pump interaction during minimum flow operation which could result in dead-heading one or more pumps.
Specifica., reviewed were the Charging (CS), Safety Injection (SI), Residual Heat Remo,
'. RH ),
Emergency Feedwater (EFW), Containment Building Spray (CBS) and Bot Acid Transfer systems.
Of these, only the CES system has a piping config ration that does not preclude the type of pump-to-pump interaction that could result in pump dead-heading.
The CBS system design includes a single recirculation line shared by the two CBS pumps.
The recirculation line configuration provides a discharge cross-connect path between the two CBS pumps which creates the potential for pump-to-pump interaction.
However, this recirculation line is utilized only during surveillance testing; and station procedures specify that during surveillance testing, only one CBS pump shall be operatad at a time. When the CBS system is not under test, but is required to be operable Statica procedures specify a valve alignment which isolates the pump discharge cross-l connect path between CBS pumps and precludes pump-to-pump interaction.
l Therefore, the CBS system piping configuration provides the potential for pump-to-pump interaction, but Station procedures preclude this interaction at all times.
8807150015 830708 l{(
PDR ADOCK 05000443 O
PDC P.O. Box 300. Seabrook. NH 03874. Telephone (603) 474-9574 1-
e
~
s
- 4
_ United States Nuclear Regulatory Commission July 8, 1988 Attention: Document Control Desk Page 2 Each of the other identified systems has a piping configuration which
. precludes pump-to-pump interaction which could lead to pump dead-heading.
Therefore, Seabrook Station safety-related systems that employ centrifugal pumps capable of. operating in_ parallel on minimum-flow are not subjectsto pump-to-pump interaction which could result in the dead-heading of a pump..
The second concern is the adequacy of the installed minimum flow capacity for each safety-related centrifugal pump.
This concern has arisen because the design criteria for establishing the minimum flow rate of a typical centrifugal pump may_have been' based solely upon pumped fluid temperature rise considera-tions without proper accounting for pump internal flow instabilities. lists the currently-installed minimum flow rates for the identified centrifugal pumps. A detailed evaluation of the adequacy of this installed minimum flow capacity has been initiated for each pump.
This evaluation will encompass the considerations delineated in Item #3 under
' Actions Requested
- in the Bulletin. A report on the results of this evaluation will be submitted to the NRC by December 31, 1988.
As explained above, the dead-heading concern is not applicable to safety-related systems at Seabrook Station. The identified centrifugal pumps have
' accumulated a short operating history during pre-operational, hot functional and surveillance testing.
The performance of each pump tv, monitored as required by the ASHE Section XI Pump Testing Program.
To the best of our knowledge, no pump performance degradation attributable to an inadequate minimum flow rate has occurred thus far.
Should you have any questions regarding this information, please contact Mr. Geoffrey Kingston at (603)-474-9574, extension 3371.
Very truly yours,
( Nd GeorgVS. Thomas Enclosure cc Mr. William T. Ruscell Mr. A. C. Cerne Regional Administrator NRC Senior Resident Inspector U. S. Nuclear Regulatory Commission Seabrook Station Region I Seabrook, NH 03875 425 Allendale Road King of Prussia, PA 19406 Mr. Victor Herses, Project Manager Project Directorate I-3 Division of Reactor Projec*.s U. S. Nuclear Regulatory Commission Washington, DC 20555
)
.' ?
United States Nuclear Regulatory Commission July 8, 1988 lq Attention:
Document Control Desk Page 3 STATE OF NEW HAMPSHIRE
'Rockingham, ss.
July 8, 1988 Then personally appeared beft me, the above-named George S. Thomas who, being duly sworn, did state that he is Vice President - Nuclear Production of.
Public Service Company of New Hampshire, that he is duly authorized to execute and file the foregoing information in the name and on the behalf of Public Service Company of New Hampshire, and that the statements therein are true to the best of his knowledge and belief.
01>nbS bcMt Beverly E. dillloway, Notaryjublic My Commission Expires: March 6, 1090 t
.i
-p.
c e
+,w-_-4 2
-.e,-
-.c c<
- T.
G ENCLOSURE 1 TO NYN-88093 Tabulation of Centrifugal Pump Installed Minimum Flow Capacity l
l I
l l
Installed Minimum Flow Capacity l
1 l
l l
I 1
l Pumo l
Gallons per Minute i
Percent of BE2 l
1 I
l l
l Charging (CS) l 66 l
18 l
I I
I l
l Intermediate 1
42 l
10 l
l Head Safety l
l l
l Injection (SI) l l
l i
I l Residual Heat l
590 - 660 1
15 l
l Removal (RH) l l
l L
I l
l l Containment l
1920 - 1935 l
63 l
l Building Spray (CBS)l l
l l
1 l
l l Boric Acid l
10 l
9 l
Transfer l
l l
l 1
l l Emergency l
270 - 290 l
31 l
l l
l l
l Note 1:
Best Efficiency Point Flow (BEP).
Percentages are approximate.