ML19350A424
| ML19350A424 | |
| Person / Time | |
|---|---|
| Site: | Grand Gulf  |
| Issue date: | 03/04/1981 |
| From: | Tedesco R Office of Nuclear Reactor Regulation |
| To: | Mcgaughy J MISSISSIPPI POWER & LIGHT CO. |
| References | |
| NUDOCS 8103160147 | |
| Download: ML19350A424 (3) | |
Text
..
,o.a ** coq'c, UNITED STATES y
y,,
f.,
g NUCLEAR REGULATORY COMMISSION C
WASHINGTON, D. C. 20555
- /sy*
e
,NO /
gp 4 1981 p
f, N Docket Hos.:
50-416/417 2
R$
S g
a 9
Mr. J. P. McGaughy, Jr.
gs Y hjI Assistant Vice President - Nuclear Production f
Mississippi Power and Light Company y
%, y"rfiOf P. O. Box 1640 Jackson, Mississippi 39205
Dear Mr. McGaughy:
SUBJECT:
INTERIM ACTIONS HEEDED FOR PLANT OPERATION PENDING FINAL RESOLUTION OF ANTICIPATED TRANSIENT WITH FAILURE TO SCRAM (ATWS)
GRAND GULF NUCLEAR STATION, UNITS 1 AND 2 In December 1978, the Nuclear Regulatory Commission (NRC) staff issued Volume 3 of NUREG-0460 which described the proposed type of plant modifications the staff believes are necessary to reduce the risk from anticipated transients with failure to scram ( ATWS) to an acceptable level. The NRC's Regulatory Requirements Review Committee completed its review in January 1979, and concurred with the staff's approach described in Volume 3 of NUREG-0460 insofar as it applies to your plant. The staff has issued requests for the industry to supply generic analyses to confrom the ATWS mitigation capacity described in Volume 3 of NUREG-0460. Subsequently, the staff issued Volume 4 of NUREG-0460, in which the staff revised its recommendations and proposed to require certain specific modifications imediately and to impose further requirements after conductino a rulemaking proceeding and issuing a regulation. Currently, the staff is planning to present its recommendations for rulemaking in ATWS to the Commission. The Commission would, by rulemaking, determine the required modifications to resolve ATWS concerns and the required scheduled for the implementation of such modifications. Your plant would, of course, be subject to the Commission's decision in this matter.
l Based on considerations described in pages 42 through 45, Volume 3 of MUREG-0460, the staff generally concluded that plants with operating licenses can continue to operate without undue risk to the health and safety of the public during the estimated 2 to 5 year period needed to implement the necessary modifications.
l However, in addition to our licensing requirertent for a recirculation pump trip to mitigate the short-term consequences of ATWS events, the staff believes the following steps should be taken as a prudent course prior to the issuance of an operating license in order to further reduce the risk from ATWS events during the interim period before the required plant modifications as determined by the Comission are completed.
I i
D03160lN
MAR 4 1981 Mr. J. P. McGaughy, Jr.
-?-
1.
An emergency operating procedure should be developed for an ATWS event, including consideration of scram indicators, rod position indicators, average power range flux monitors, (APRH), reactor vessel level and pressure indicators, relief valve and isolation valve indicators, and containment temperature, pressure and radiation indicators. The emergency operating procedure should be sufficiently simple and unambiguous to permit prompt operator recognition of an ATWS event.
2.
The emergency operating procedure should describe actions to be taken in the event of an ATWS including consideration of manually scraming the reactor by using the manual scram buttons followed by changing the operation mode switch to the shutdown position, stripping the feeder breakers on the reactor protection system power distribution buses, scraming individual control rods from the back of the control room panel, tripping breakers from plant auxiliary power source feeding the reactor protection system, and valving out and bleeding off instrument air to scram solenoid valves. These actions must be taken imediately after detection of an ATWS event. Actions should also include prompt initiation of the residual heat removal system in the suppression pool cooling mode to reduce the severity of the containment conditions; and actuation of the standby if quid control system if a scram cannot be made to occur.
Early operator action as described above, in conjunction with a recirculation pump trip, would provide significant protection for some ATWS events, namely those which occur (1) as a result of comon mode failure in the electrical portion of the scram system and some portions of the drive system, and (2) at low power levels where the existing standby liquid control system capability is sufficient to limit the pool temperature rise to an acceptable level.
l We are currently reviewing your ATWS emergency operating procedure submitted to us by letter dated January 30, 1981. Our review will include a visit to your simulator and plant, to determine the feasibility of implementing your proposed procedures through operator simulation of the steps. Our evaluation must conclude that an acceptable procedure and operator training are completed prior to the issuance of a full power operating license.
Sincerely,
, lff. c.- a. '.
l
~
Robert L. Tedesco, Assistant Director for Licensing Division of Licensing cc: See next page.
l
(
MAR 4 1981 Mr. J. P. McGaughy cc: Robert B. McGehee, Esq.
Wise, Carter, Child, Steen & Caraway P. O. Box 651 Jackson, Mississippi 39205 Troy B. Conner, Jr., Esq.
Conner, Moore & Corber 1747 Pennsylvania Avenue, N. W.
Washington, D. C.
20006 Mr. Adrian Zaccaria, Project Engineer Grand Gulf Nuclear Station Bechtel Power Corporation Gaithersburg, Maryland 20760 Mr. Alan G. Wagner, Resident Inspector P. O. Box 469 Port Gibson, Mississippi 39150 Mr. N. L. Stampley, Sr. Vice President Engineering, Production & Construction P.O. Box 1640 Jackson, Mississippi 39205 Mr. L. F. Dale Nuclear Project Manager P.O. Box 1640 Jackson, Mississippi 39205 Mr. John Richardson P. O. Box 1640 Jackson, Mississippi 39205
-.