ML20032C689
| ML20032C689 | |
| Person / Time | |
|---|---|
| Site: | Pilgrim |
| Issue date: | 11/04/1981 |
| From: | Howard J BOSTON EDISON CO. |
| To: | Ippolito T Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20032C690 | List: |
| References | |
| 81-257, NUDOCS 8111100743 | |
| Download: ML20032C689 (7) | |
Text
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h, Sta STO N EDISON COMPANY 5D0 BOYLSTON STREET BOSTLN. MASSACHUSETTS O2199 J. EDWARD HOWARD eacs enas otest souctaAs November 4,1981 BECo. Ltr. #81-257
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Proposed 1-09 N{C{ /()
Mr. Thomas A. Ippolito, Chief Operating Reactors Branch #3 E,
Division of Operating Reactors
- NOV0 9 7937, p
""Qu"" m,3, Office of' Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission 1
Washington, D.C.
20555
'<.sy License No.'DPR-35,
Docket No. 50-293 Proposed Change to Technical Specifications on Standby Gas Treatment System and Control Room High Efficiency Air Filtration System Referer.ce:
(1) BECo Ltr. #81-230, dated September 30, 1981 (2) BECo Ltr. #81-232, dated October 2,1981
Dear Sir:
p roduction
/ursuant to Section 50.90 of the Commission's Rules and Regulations, Boston Edison Company hereby proposes the following modification to Appen' dix A of' Operating License No. DPR-35.
Proposed Change The proposed change is applicable to the following Pilgrim Station Limiting Conditions for Operation.
3.7.B.
1.
Standby Gas Treatment System (Page 158)
(AttachmentA) c.
From and after the date that one train of the Standby Gas
/g/r:
Treatment System is made or found to be inoperable for any reason, continued reactor operation or fuel handling is gpoo.co permissible only during the succeeding seven days providing i
that within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> ard daily thereafter, all active components of the other standby gas treatment train shall be demonstrated to be operable.
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BosION, EQtRON COMPANY
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Mr. Thomas A. Ippolito, Chief November 4,1981
.Page 2 3.7.B. 1.
Standby Gas Treatment System (Continued) (Page 158A) (Attachment A) e.
Except as specified. in 3.7.B.1.c, both trains of the standby gas treatment system shall be operable during fuel handling operations.
If the system is not operable fuel movement shall not be started (any fuel assembly movement in progress may be completed).
3.7.B. 2.
Control Room High Efficiency Air Filtration System (Page 1588) (Attachment A)
Except as specified in Specification 3.7.B.2.c below, both a.
trains of the Control Roon High Efficiency Air Filtration System used for the processing of inlet air to the control roon under accident conditions and the diesel generator (s) required for operation of each train of the system shall be operable whenever secondary containment integrity is required 4
and during fuel handling operations.
l 3.7.B. 2.
Control Room High Efficiency Air Filtration System (Continued) (Attachment A)
S Fron and after the date that one train of the Control Room c.
High Efficiency Air Filtration System is made or found to be incapable of. supplying filtered air to the control room for any reason, reactor operation or refueling operations are permissible only during the succeeding 7 days.
If the system is not made fully operable within 7 days, reactor shutdown shall be initiated and the reactor shall be in cold shutdown within the next 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> and irradiated fuel handling operations shall be terminated within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />.
(Fuel handling operations in progress may be completed.)
The proposed change consists of adding a footnote, applicable to each of the above Limiting Conditions of Operation which provides conditional relief from each LC0 for the period November 4, '1981 to November 24, 1981, during which fuel handling operations are in progress.
subject to date of receipt of NRC approval of this change.These dates are based on a 2 t
Reason For Change l
A recent engineering analysis, performed in response to IE Bulletin #80-11, "Masonary Wall Design" has revealed that three masonary walls located on el. 51' i
of the Turbine Building (212.1, 65.19,196.0) will not retain their' structural integrity following certain design basis events: High Energy Pipe Break Outside Containment (pB0C), Tornado Depressurization and Seismic.
Failure of these i
walls would cause loss of certain cables which would,in turn, cause a loss of i
power to portions of the Standby Gas Treatment System (Train A), Control Room High Efficiency Air Filtration System (Train A), RHR Shutdown Cooling (Train A)
.and Standby Liquid Control.
Failure of wall 196.0 could affect operability of Standby Gas Treatment System B; however, current plant practices as discussed i
-further (see seismic) precludes any such concerns.
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E'CTON EDIEON COMPANY.
' Mr. Thomas A. Ippolito, Chief' November 4,1981 Page 3 Corrective design modifications have been developed to restore the wall's design safety margins. All three modifications are presently in the construction phase. The scheduled completion date is December 1,1981.
l During the requested period of conditional relief from the stated sections of Technical Specifications, Boston Edison shall implement the following interim actions to address each design base event of concern:
High Energy Pipe-Break Outside Containment This event has no potential impact upon system operability while the reactor is in the cold shutdown and the refueling mode.
Tornado Depressurization A temporary operating procedure shall be issued which requires termination of irradiated fuel handling operations in the event a Tt.nado Watch is issued for the immediate area.
(A fuel handling operation in progress may be completed.)
Seismic To assure. availability and operability of the non-impacted trains of the Standby Gas Treatment System and Control Room High Efficiency 4
Air Filtration System; these systems shall be continuously operated during all irradiated fuel. handling activities. A temporary procedure.
shall be issued which delineates instructions for-the operating personnel to ascertain system operability and which requires tennination of irradiated fuel handling operations should either of the continually running systems be found or made to be inoperable.
This proposed mode of operations provides an additional level of confidence in the availability of the equipment designed to mitigate the consequences of a fuel drop accident. This conservatism is i
. apparent when compared to Bases 3.7.B.1.
"Only one of the two Standby Gas Treatment Systems (SBGTS) is needed to maintain the secondary containment at a 0.25 inch of water negative pressure upon containment isolation.
If one system is found to be inoperable, there is no imediate threat to the containment system performance and reactor operation or refueling activities may continue while repairs are being made.
In the event one SBGTS is inoperable, the redundant system will be tested daily.
This substantiates the availability of the operable system and justifies conti:.ued reactor or -
i refueling operations."
The specific failures which would render the (RHR) Shutdown Cooling - A 4
inoperable would be the " shorting" of logic control cables for the j
M01001-43A and !91001-43C shutdown cooling suction valves.
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COLTON EDIEON COMPANY.
Mr. Thomas A. Ippolito, Chief November 4, 1981 Page 4 The effect is to cause the appearance of a loss of suction path for each respective RHR pump, thus initiating a pump trip. The pump trip is an equipment protective function. This potential failure mode of Shutdown Cooling Loop A will be compensated for by putting in place a "Special Order" to specify the actions to be implemented by operations personnel following a wall failure which renders the RHR pumps inoperable.
The specific failure that would render the Standby Gas Treatment B inoperable, would be the loss of VEX-210B fan discharge damper (M0-N-113).
However, current plant practice has this outlet damper failed in the open position due to environmental qualification considerations, ie., IE Bulletin #79-01B. This practice will continue to be in effect for the time frame of Tech. Spec. relief.
The failure that would affect the Standby Liquid Control Sys:em, (loss of power to the tank heater), would not prevent the sy: tem from performing its safety function. Although planned contro. *od testing and Technical Specification Section 3.4.A.1 dictate a need for system availability during the requested relief time frame, it should be noted that system operability is not jeopardized through the loss of power to the tank heater as demonstrated below:
Per design bases the SBLC must be capable of delivering at least 3960 gallons of 9.6% sodium pentaborate solution into the reactor. The saturation temperature of this solution is 40 F.
Concentration is directly proportional to temperature. Our normal concentration is 12.4% with a saturation temperature of 54 F.
Tank room temperature is maintained between 65 F and 100 F.
The sodium pentaborate temperature at present is 103 F with room temperature at 85 F.
The SBLC tank heaters are designed to operate between 57 F and 85 F liquid temperature. This indicates an extremely low heat loss across the insulated tank wall and it can be reasonably assumed that liquid temperature will not drop to saturation temperature if room temperature is maintained 65-100 F, as designed. As such, it is concluded that the SBLC system will operate as desired for a minimum of ten hours after the loss of j
power to the tank heater and since the time frame for SBLC injec-tion, if necessary, is of a short duration after the initiating event, no Technical Specification relief is considered necessary.
Safety Considerations The proposed changes have been reviewed and the Safety Evaluation is provided in Attacanent B.
The Safety Evaluation concluded that the proposed change does not represent an unreviewed safety question and there is reasonable assurance that the public health and safety will not be endangered. The proposed change has been reviewed and approved by the Operations Review Committee and reviewed by the Nuclear Safety Review and Audit Committee.
~ CO", TON EDI'lON COMPANY Mr. Thomas A. Ippolito, Chief November 4,1981 Page 5 Schedule of Change Boston Edison Company requests expeditious approval of this proposed Technical Specification in order that it may be put into effect between November 4 and November 24, 1981 or for a period of 20 days from the date of NRC approval.
Fee Consideration In accordance with Section 170.12 of the Commission's Regulations, Boston Edison proposes this license change as Class III. A;cordingly a cteck for Four Thousand Dollars ($4,000) is enclosed.
Your immediate attention to this request would be greatly appreciated.
Very truly yours, 6.
8t1 3 signed originals and 37 copies Commonwealth of Massachusetts)
County of Suffolk
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The'1 personally appeared before me J. Edward Howard, who, being duly sworn, did state that he is'Vice President - Nuclear of Boston Edison Company, the applicant herein, and that he is duly authorized to execute and file the submittal contained herein in the name and rn behalf of Boston Edison Company and that the statements in said submittal are true to the best of his knowledge and belief.
My Commission expires:
// d, /MM
[d Nota'rf Public ~
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ATTACHMENT B SAFETY EVALUATION FOR TECHNICAL SPECIFICATION CHANGE ON THE STANDBY GAS TREATMENT SYSTEM AND THE CONTROL ROOM HIGH EFFICIENCY AIR FILTRATION SYSTEM Pursuant to Section 50.59 of the Commission's Rules and Regulations, Boston Edison has performed a safety evaluation of the proposed change to Appendix A of Operating License No. DPR-35. The following areas of concern were addressed in the performance of the safety evaluation:
Components Which Require Power Restoration In The Event Of Failure Of Block Wall 212.1:
Five (5) safety related systems were identified that would not maintain their intended design function during design based events:
Standby Gas Treatment (SGTS) - Train A (Power)
Control Room Ventilation - Train A (Power)
Residual Heat Removal - Train A Reactor Core Isolation Cooling Standby Liquid Control - Tank Heater 65.19 Three (3) safety related systems were identified that would not maintain their intended design function during design based events:
Control Room Ventilation - Train A (Power)
Standby Liquid Control - (Tank Heater)
Standby Gas Treatment - Train A (Power) 196.0 Three(3) safety related systems were identified that would not maintain their intended design function during design based ever.ts:
Standby Liquid Control (Tank Heater)
Control Room Ventilation - Train A Standby Gas Treatment (SGTS) - Train B By utilizing Appendix G, Station Nuclear Safety Operational Analysis, of the PNPS 1 FSAR, only three (3) of the five (5) systems; namely, Control Room Ventilation, Standby Gas Treatment and Residual Heat Removal - Train A were found to be rt ;uired in the cold shutdown and the refueling modes.
However,-system operability requirements have been obviated through the implementation of special compensatory measures.
The other systems affected by the failure of walls.are either not required for the modes of plant operation anticipated during the duration of the change or are not rendered inoperable.
Page 1 of 2 vee-
Probability Estimate of Fuel Handling Accident in Conjunction with Block Wall Failure The probability of a fuel handling accident due to random failure coincident with block wall failure was not. calculated, as it would reasonably be several orders of magnitude below the probability of common cause failures.
The total probability, P.
f a fuel handling accident at the same time as block T
wall failure is:
P (block wall failure caused by tornado) + P (block wall failure due to P
=
T while handling fuel earthquake while handling fuel) 8.2 x 10-6/ refueling + 2 x 10 / refueling = 1.0 x 10-5/ refueling
-6
=
)
4 The PBOC event is not considered to be a threat, based on the fact that the reactor plant is shutdown, cooled down, depressurized and open to the atmosphere.
Radiological Offsite Effects Of A Refueling Accident Assuming The SGTS Is Inoperable i
The design base Fuel Handling Accident was analyzed assuming that the SGTS is inoperable.
This analyses is consistent with the PNPS-1 Safety Evaluation Report with the i
exception of certain methods and assumptions recommended in Safety Guide 25 and l
Regulatory Guide 1.145 which are more recent than the SER.
4 The results of this analyses indicate that the offsite thyroid dose which would 4
result from a fuel drop at or after 120 hours0.00139 days <br />0.0333 hours <br />1.984127e-4 weeks <br />4.566e-5 months <br /> after shutdown with the SGTS inoperable would result in a site boundary dose of about 32 Rem to the thyroid i
and less than 1 Rem to the whole body or skin. The values are approximately 10% (or less) of the applicable 10CFR100 limits. Therefore, the SGTS would not be required to limit offsite doses resulting from a Fuel Handling Accident, provided fuel movement occurs later than 120 hours0.00139 days <br />0.0333 hours <br />1.984127e-4 weeks <br />4.566e-5 months <br /> after reactor shutdown.
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Based on the above results, in conjunction with the interim operating measures delineated in attached BECo. Letter #81-257, the proposed change does not constitute an unreviewed safety question and, consequently, there is reasonable
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assurance that the public health and safety will not be endangered.
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