ML20065N738
| ML20065N738 | |
| Person / Time | |
|---|---|
| Site: | Grand Gulf  |
| Issue date: | 04/19/1994 |
| From: | Hutchinson C ENTERGY OPERATIONS, INC. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| GNRO-94-00059, GNRO-94-59, IEB-93-002, IEB-93-2, NUDOCS 9404280057 | |
| Download: ML20065N738 (6) | |
Text
..
'#'ENTERGY l"%"5s?"*" "*' '"*'
Port Gbson.MS 39150 Tel 601437 2600 C. R. Hutchinson April 19,1994 w eet canae Grarx1 G# Nuciear SMton U.S. Nuclear Regulatory Commission Mail Station P1-37 i
Washington, D.C.
20555 Attention:
Document Control Desk
Subject:
Grand Gulf Nuclear. Station Docket No. 50-416 License No. NPF-29 Response to NRC Bu'.letin 93-02 Supplement 1 GNRO-94/00059 Gentlemen:
This submittal provides the Grand Gulf Nuclear Station i
(GGNS) response to NRC Bulletin (NRCB) 93-02 Supplement 1, " Debris Plugging of Emergency Core Cooling Suction i
Strainers".
The Bulletin was issued to inform' licensees about the vulnerability.of ECCS suction strainers, and to-request that licensees take appropriate actions co ensure reliability of the ECCS regarding the vulnerabii.ity of the suction strainers to' clogging.
The attachment is the GGNS response to the requested actions.
]
i This information is being submitted under oath and affirmation in accordance with 10CFR50.54(f). Please contact Brian Blanche at-601-437-6475 should you have any questions or require additional information regarding this matter.
Yours truly, l
W CRH/BJB/bjb attachment: Response to NRC Bulletin 93-02 Supplement 1 l
cc:
(See Next Page) l G9404121.
n 9404290057 940419 hI I
PDR ADOCK 05000416 l
l L
'Q PDR
4 April 19, 1994 GNRO-94/00059 Page 2 of 3 cc:
Mr. R. H. Bernhard (w/a)
Mr.
H. W. Keiser (w/a)
Mr.
R. B. McGehee (w/a)
Mr. N.
S. Reynolds (w/a)
Mr.
H. L. Thomas (w/o)
Mr. Stewart D. Ebneter (w/a)
Regional Administrator U.S. Nuclear Regulatory Commission Region II 101 Marietta St.,
N.W.,
Suite 2900 Atlanta, Georgia 30323 Mr. P. W. O'Connor, Project Manager (w/2)
Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Mail Stop 13H3 Washington, D.C.
20555 I
i I
l G9404121 l
BEFORE THE UNITED STATES NUCLEAR REGULATORY COMMISSION LICENSE NO. NPF DOCKET NO. 50-416 IN THE MATTER OF MISSISSIPPI POWER & LIGHT COMPANY and SYSTEM ENERGY' RESOURCES, INC.
and SOUTH MISSISSIPPI ELECTRIC POWER ASSOCIATION and ENTERGY OPERATIONS, INC.
AFFIRMATION
.j I, D.
L.
Pace, state that I am General Manager, Plant Operations GGNS of Entergy Operations, Inc.; that on behalf of Entergy Operations, Inc., System Energy Resources, Inc.,
j and South Mississippi Electric Power Association I am authorized by Entergy Operations, Inc. to sign and file with the Nuclear Regulatory Commission, this response to NRC Bulletin 93-02, Supplement 1 for the Grand Gulf Nuclear Station; that I signed this application as General Manager, Plant Operations GGNS of Entergy Operations, Inc.; and that the statements made and the matters set forth therein are true and correct to tl.e best of my knowledge, information and belief.
/ l ' ~.L/
D.
L.
Pace-M~N h STATE OF MISSISSIPPI COUNTY OF ELAIBONE Orefs Public, in and SUBSCRIBED AND SWORN TO before me, a Notary / M this day of for nty and Sta ove named,
/-
(SEAL) b
~
Notary Public d
M y s.c o mrg i s s f or3 g.i g e s,:
> m
- 1.. ! FJ s, c ;r. w7 P 17.'-
S U C;G '21 Mia ; ; g -'
G9404121
a
_m o
AttschmEnt 1 to GNRO-94/00059 l
i Response to NRC Bulletin 93-02 Supplement 1 G9404121
4 to GNRO-94/00059 Page 2 of 3 Requested Action 1 Provide training and briefings to apprise operators and other appropriate emergency response personnel of the information contained herein and in the referenced information notices regarding the potential for suppression pool strainer clogging.
Response
Formal training is in progress for licensed and non-licensed Operations Department and appropriate emergency response personnel.
The training focuses on control room indications and operator responses to ECCS strainer clogging, including the implementation of Emergency Operating Procedures.
The BWR Owners' Group letter BWROG-94029 dated March 15, 1994, " Operator Guidance For Potential Blockage Of ECCS Pump Suction Strainers",
was used as a guide for this training.
On-site and industry events describing ECCS suction strainer clogging including the Perry and Barseback events were also presented as part of this training.
Training of Operations and Emergency Response personnel will be completed within 90 days of the date of this bulletin.
Requested Action 2 Assure that the emergency operating procedures make the operator aware of possible indications of ECCS strainer clogging and provide guidance on mitigation.
Response
The GGNS Emergency Operating Procedures provide operator guidance based upon plant symptoms rather than specific events.
Symptomatic procedures do not require the operator to diagnose the event.
With the training which has occurred on strainer clogging recognition, the operator will be aware of another method for potential loss of ECCS and utilize the Emergency Procedure success paths to restore ECCS via alternate water suction paths or implement alternate injection water sources.
B_equested Action 3 Institute procedures and other measures to provide compensatory actions to prevent, delay, or mitigate a loss of available NPSH margin under LOCA conditions.
Such measures should be consistent with providing the design basis emergency system functions for core and containment cooling.
Response
At the end of the last refueling outage, the suppression pool was cleaned to remove any items and debris that could potentially clog the ECCS suppression pool strainers.
As an added measure, due to the heightened awareness of potential for debris which could clog the suppression pool strainers, the drywell vent annulus was also cleaned.
Also, a walk-down of the drywell was G9404121 l
. to GNRO-94/00059 Page 3 of 3 performed to assess insulation integrity and perform repairs on degraded insulation.
The procedure governing plant insulation has been revised to identify and repair any degraded insulation which could be introduced into the suppression pool.
To retain the cleanliness of the suppression pool between refueling outages, signs have been posted notifying personnel entering containment of specific controls on materials that impose potential plugging hazards to the ECCS strainers.
The operator building rounds sheets have been changed to add a step which requires a visual check of accessible areas of the suppression pool and initiation of a work document to remove any identified foreign material.
Other steps have also been taken, such as removal of the fire hose covers inside containment.
The procedure for the fire hose station check has also been revised to provide a periodic verification that fire hose covers have not been replaced inside containment.
Grand Gulf has an installed suppression pool cleanup system designed to maintain water cleanliness consis. tent with Updated Final Safety Analysis standards.
.The procedures governing the control of work on plant equipment and housekeeping will be revised to alert plant personnel to the potential hazards which exist when working inside containment with material that could potentially clog the ECCS suction strainers.
This procedural change will be completed within 90 days of the date of this bulletin.
j GGNS is actively participating in the BWROG ECCS Suction Strainer Committee.
As a result of information received from this group, as well as the heightened awareness of the industry on this issue, a Suppression Pool Task Force was formed to provide recommendations to the GGNS Plant Safety Review Committee.
One of the items recommended by the task force was the analysis of a backflush method for the suppression pool strainers using existing system flow paths.
The analysis of strainer backflush methods is still in progress, and the most promising method (s) will be proceduralized to provide operator guidance on available means for suppression pool strainer backflushing.
This procedural guidance will be completed within 90 days of the date of this bulletin.
G9404121
_