ML20215E587
| ML20215E587 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 06/09/1987 |
| From: | Fiedler P GENERAL PUBLIC UTILITIES CORP. |
| To: | Hebdon F NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| NUDOCS 8706220035 | |
| Download: ML20215E587 (7) | |
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i GPU Nuclear Corporation Nuclear
- = = 388 Forked River, New Jersey 08731-0388 609 971-4000 Writer's Direct Dial Number:
June 9,1987 Mr. Frederick J. Hebdon, Acting Chief Reactor Projects Branch No.1 Division of Reactor Projects U.S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, PA 14906 i
Dear Mr. Hebdon:
Subject:
Oyster Creek Nuclear Generating Station Docket No. 50-219 IE Inspection 50-219/86-38 Notice of Violation Enclosed is GPU Nuclear's response to Appendix A of your letter dated March 25, 1987.
This response is submitted in accordance with 10CFR2MI.
An extension of the response period was obtained from Mr. William Bateman, the Senior NRC Resident Inspector at the Oyster Creek site, on April 23, 1987.
GPU Nuclear concurs with the cited procedure violations.
However, GPUN does 'not agree with the statements made in your letter relative to " good, i
conservative operating practices".
GPUN policy and management direction has been and continues to be that safe operation of the plant - is the first priori ty.
The Technical Specifications are based on conservative l
calculations, tests, and engineering judgments by GPUN and the Nuclear Regulatory Commission which assure safe operation of the plant.
The bases of i
the Technical Specifications define the required safety margin (conservatism) which cannot be reduced without review and approval by regulatory authorities (10CFR50.59).
The Nuclear Regulatory Commission has determined, as stated in j
the Operating License, that operation in accordance with the Technical Specification will not be inimical to the health and safety of the public, i
Therefore, such operation provides an appropriate level of conservatism to assure safe operation of the plant while allowing the public to receive the l
benefits of nuclear electrical generation.
j In the past, in relation to the extent and severity of plant operational problems, GPUN management has restricted plant operations in a manner that provided additional conservatism beyond the requirements of the Technical l
Specifications.
These voluntary restrictions were imposed based on due consideration of GPUN's commitment to safety in fulfilling our responsibility l
to the public.
In this particular event, immediate action was taken (a half scram and an i
administrative rod block were inserted) to assure plant safety; after which, cognizant personnel referred to the Technical Specifications to assess what j
options existed -by law-for the plant situation.
Personnel reviewed the i
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'. specific conditions and initiated an evaluation to determine the appropriate course of action.
The plant startup was suspended to allow sufficient time to resolve the IRM deficiencies.
Supervisory personnel were contacted, at home in some cases, while shift personnel continually reviewed and evaluated operational conditions for determining a course of action that was consistent with safe operation and that would avoid unnecessary cycling of the plant to the extent possible.
Plant equipment was not manipulated for the purpose of assuring literal compliance with the Technical Specifications.
Such mani pul ations were made to assure the ability of equipment to accurately reflect actual plant conditions during the period of evaluation.
Specifically, as discussed in the enclosure, LPRMs were bypassed to allow the APRMs to more accurately reflect existing conditions in higher power core regions.
Although it is recognized that procedures were not strictly adhered to, there was no attempt to proceed with the startup at the expense of safety.
Those measures taken were to assure operation in accordance with the Technical Specifications which establish an appropriate level of conservatism to assure safe operation.
l If you should have any questions please contact Mr. George Busch, Oyster Creek Licensing at (609)971-4909.
Very truly yours, i
P' nieRTe Vice President and Director Oyster Creek 1
PBF/GB/dmd Enclosure cc: Mr. William Russell, Administrator Region I U.S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, PA 19406 Mr. Alexander W. Dromerick U.S. Nuclear Regulatory Commission 7920 Norfolk Avenue, Phillips Bldg.
Bethesda, MD 20014 Mail Stop No. 316 NRC Resident Inspector Oyster Creek Nuclear Generating Station Forked River, NJ 08731
ENCLOSURE Violation Technical Specification 6.8.1 requires that written procedures shall be established, implemented, and maintained.
(1 ) Station Procedure 2000-RAP-3024.01, Alarm Response Procedures, Reactor Neutron Monitors, Annunciator Window G-2-e, Rev. 3, requires a plant shutdown if more than one IRM channel per trip system becomes inoperable while in the startup mode.
Contrary to the above, during a plant startup on December 27, 1986, IRMs 16 and 18 on RPS channel 2 were declared inoperable with the mode switch in startup and the plant was not shutdown.
(2) Station Procedure 402.2, IRM Operation During Startup, Rev. 7, requires approximately one decade of overlap between the IRM and APRM nuclear instrumentation to ensure proper response, j
Contrary to the above, during a plant startup on December 27, 1986, APRM instrumentation was used to monitor reactor power without having first achieved approximately one decade of overlap between the IRMs 2
and APRMs.
(3) Station Procedure 312, Reactor Containment Integrity and Atmosphere Control, Rev. 37, requires nitrogen temperature be monitored and maintained at 65*- 80*F during inerting of the drywell and torus.
Contrary to the above, during inerting on December 27,1986 and January 6,1987, nitrogen temperature was maintained between 55*-
60*F.
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Response
GPU Nuclear concurs with the violation.
(1) Violation of Station Procedure 2000-RAP-3024.01 After subsequent investigation it was determined the "Hi-Hi/IN0P II" alarm was actuated, however, the alarm was subsequently cleared (IRM 18 was bypassed and a half scram was inserted).
At this time, the operator was referring to the Technical Specifications to determine required actions due to the bypassing of IRM 18 and the apparent failure of IRM 16. After discussion with the Operations Control Manager, the Shift Technical Advisor, the Group Shift Supervisor, the Group Operations Supervisor, and the Core Engineering Manager (all of whom are currently or previously licensed individuals), supervisory personnel decided tha IRM scram function in the startup mode was not required provided the' APRMs were operable as evidenced by a reading of at least
e 2/150 of full scale.
This decision is in accordance with the Oyster Creek Technical Specifications, Section 3.1, Table 3.1.1.
Note (d) to Table 3.1.1 specifies that "the IRM shall be inserted and operable until the APRMs are operable and reading at least 2/150 full scale."
It should be recognized that notes to Table 3.1.1 provide requirements as specified in Section 3.1. A and therefore exceed the status normally associated with the word " note".
Station procedure 2000-RAP-3024.01 provides a more conservative approach upon receiving the "IRM Hi-Hi/INOP II" alarm (annunciator window G.2.e).
This approach assures the function of the IRM range scram.
Based on the operability of the APRMs and thei r associated scram function, it was decided the IRM scram function was not requi red.
Therefore, the appropriate level of protection was maintained and a plant shutdown due to IRM inoperability was not required.
Although station procedure 2000-ADM-3214.01 would require a more conservative approach, the actions taken were in accordance with the Technical Specifications which also provides a
conservative approach as indicated in the basis of specification 3.1 as follows:
"One IRM channel in each of the two trip systems may be bypassed without compromising the effectiveness of the system.
There are few possible sources of rapid reactivity input to the system in the low power low flow condition.
Effects of increasing pressure at zero or low void content are minor, cold water from sources available during startup is not much colder than that al ready in the system, temperature coefficients are small, and control rod patterns are constrained to be uniform by operating procedures backed up by the rod worth minimizer.
Worth of individual rods is very low in a uni form rod pattern.
Thus, of all possible sources of reactivity input, uniform control rod withdrawal is the most probable cause of significant power rise.
Because the fl ux distribution associated with uniform rod withdrawals does not involve high local peaks, and because several rods must be moved to change power by a significant percentage of rated, the rate of power rise is very slow.
Generally the heat flux is in near equilibrium with the fission rate.
In an assumed uniform rod withdrawal approach to the scram level, the rate of power rise is not more than five percent of rated per minute, and three operable IRM instruments in each trip system would be more than adequate to assure a scram before the power could exceed the safety i
limit.
In many cases, if properly located, a single operable IRM channel in each trip system would suffice."
It should be noted that during the time IRM 18 was bypassed and IRM 16 was declared inoperable an administrative rod block was inserted in addition to a half scram and no attempt to withdraw control rods was made.
The hal f scram was subsequently cleared upon established APRM operability, however, the administrative rod block was maintained to prevent rod withdrawal.
The prime consideration for establishing the nuclear instrumentation configuration at that time was to allow sufficient time for the evaluation of the IRM problems while not allowing further power escal ation.
Subsequently, as discussed in the Inspection Report, it was determined that IRM 16 had been operable during this entire period.
GPU is currently evaluating the IRM operability criteria for consistency with respect to the Technical Specifications and stations procedures.
e
-(2) Violation of Station Procedure 402.2 GPUN concurs with the violation.
Station Procedure 402.2 refers to verifying proper overlap (approximately one decade) prior to entering into the IRM range as well as prior to entry into the APRM range.
In entering the IRM range from the SRM range, this determination is more obvious and clearly defined in station procedure 201.1
(" Approach to Critical") which identifies the required overlap as an IRM reading of 50% of range one (1).
In this event, proper overlap was not established, due to a lack of clear guidance on establishing such an overlap.
The operators relied on establishing APRM operability.
Operability of the APRM instrumentation is defined in the Technical Specifications as the clearing of LPRM downscales with the APRM reading 2/150 percent full scale.
This criteria for APRM operability is reflected in station procedure 402.2 which also states "if downscale LPRM's have cleared, the reactor may be placed in the RUN mode without entering IRM range 10."
The act of bypassing LPRM inputs to the APRMs is a conservative action.
Power level as indicted on the APRMs is an average value based on LPRM inputs from various core regions.
Bypassing of lower reading LPRMs deletes the LPRM signal from the averaging network.
Therefore, LPRMs which sense extremely low levels of neutron flux are prevented from skewing the average (read on the APRMs) toward unrealistic lower levels.
Consequently, the Reactor Protection System is more sensitive to reactor power changes and closer to its trip setpoints due to higher reading APRMs.
APRM operability is further assured by higher indications and changes in the APRM levels coincident with the act of bypassing the lower reading LPRMs.
(3) Violation of Station Procedure 312 i
GPU Nuclesr concurs with the violation.
Station Procedure 312 " Reactor i
Containment Integrity and Atmospheric Control" has been revised to allow operation of the Nitrogen Inerting System under its current configuration and limitations.
GPU Nuclear is currently evaluating the performance of the Nitrogen Inerting System to identify any changes that may be needed.
Should modifications be desirable, GPU Nuclear will implement such changes during the next refueling outage.
Corrective Action i
As stated previously, station procedure 312 has been revised.
{
l GPUN has initiated a review of the procedures pertaining to this event as l
well as other procedures which address nuclear instrumentation operability.
This review has revealed some ambiguity among these procedures and with regard to the Technical Specification requi rements.
These procedures will be revised to clarify the nuclear instrumentation J
overl ap cri teria and the requi red actions in response to instrument l
failures.
i
r Although the actions taken by the operators with regard to nuclear l
instrumentation are considered technically acceptable in assuring plant I
safety, plant procedures were not followed.
This event will be required reading for all operators and incorporated into the operator training program to illustrate the importance of procedural compliance.
Full compliance will be achieved by August 15, 1987.
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