CEO-88-002, Application for Proposed Amend 130 to License DPR-54,adding Operating Requirements Designed to Provide Proper Limitations & Conditions on Reactor Bldg Pressure Equalization Operations During Power Operation.Fee Paid
| ML20196A219 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 06/21/1988 |
| From: | Firlit J SACRAMENTO MUNICIPAL UTILITY DISTRICT |
| To: | Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20196A221 | List: |
| References | |
| CEO-88-002, CEO-88-2, NUDOCS 8806290490 | |
| Download: ML20196A219 (11) | |
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'hSMUD SACRAMENTO MUNICIPAL UTILITY DISTRICT O 6201 S Street P.o. Box 15830, Sacramento CA 95852183o,(916) 452 3211 AN ELECTRIC SYSTEM SERVING THE HEART OF CALIFORNIA
'JUN 211989 CE0 88-002 Director of Nuclear Reactor Regulation V. S. Nuclear Regulatory Commission Mail Station Pl-137 Washington, DC 20555 Docket No. 50-312 Rancho Seco Nuclear Generating Station License No. DPR-54 PROPOSED AMENDMENT N0.130
Dear Sir:
In accordance with 10 CFR 50.90, the Sacramento Municipal Utility District proposes to amend Operating License DPR-54 for Rancho Seco and therefore submits Prn sed Amendment No. 130.
By letter da ad December 4, 1984, the Commission issued its SER confirming the ability of the 12-inch equalization valves to close against the buildup of Containment pressure in the event of a DBA/LOCA. Before the Reactor Building pressure equalization valves can be used during power operation, a Technical Specification change is required.
Proposed Amendment No.130 places operating requirements into the Technical Specifications which are designed to provide proper limitations and conditions on Reactor Building pressure equalization operations during power operation.
Proposed Amendment No.130 also modifies an existing purge system operation requi rement.
Attachment I contains the Safety Analysis Report and the No Significant i Hazards Consideration for the changes made by Proposed Amendment No.130. j Attachment II contains the Technical Specification pages affected by Proposed i Amendment No.130. l 00I gBP27pycegg8g;,2 #ch am r
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RANCHO SECO NUCLEAR GENERATING STATION D 1444o Twin Cities Road, Herald, CA 95638 9799;(209) 333 2935
l Director of HRR 1 Pursuant to 10 CFR 50.91(b)(1), the Radiological Health Branch of the California State Department of Health Services has been informed of this proposed ainandment by mailed copy of this submittal.
Enclosed is a check in the amount of $150.00, as required by 10 CFR 170.21, "Schedule of Fees".
Please contact me if you have any questions. Members of your staff with questions requiring additional information or clarification may contact Mr.
Richard Mannheimer at (209) 333-2935, extension 4919.
State of California SS County of Sacramento Joseph F. Firlit, being first duly sworn, deposes and says: that he is Chief Executive Officer, Nuclear, of Sacramento Municipal Utility District (SMUD), the licensee herein; that he has executed the foregoing document; that the statements made in this document are true and correct to the best of his knowledge, information, and belief, and that he is authorized to execute the document on behalf of said licensee.
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Jgseph t . Firlit Chief Executive Officer, Nuclear Subscribed and affirmed to before me this dI day of lu-r h ,
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< g y 4 '/hEb Robin Michell a ,ug g y
, mim .. ,7 Notary Public Attachments cc: A. D' Angelo, NRC, Rancho Seco i J. B. Martin, NRC, Walnut Creek ;
J. S. McGurk, State of California l
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i ATTACHMENT I Safety Analysis Report and No Significant Hazards Consideration 1
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4 PROPOSED AMENDMENT NO. 130 LOG NO. 649 Safety Analysis PAGE 1 of 8 ;
SAFETY ANALYSIS REPORT Descriotion of Change 1 Effect Technical Specification (Tech Spec) changes to address operation of the 12-inch Reactor Building pressure equalization valves when the plant is in the "Power Operation" mode (>2% of rated power as defined by Tech Spec 1.2.5).
Also, effect Tech Spec changes to appropriately define the purge system operation requirements.
Add reference to Reactor Building equalization isola lon in Tech Spec Table 3.5.1-1, Process Instrumentation, item 9.
Remove the "at cold shutdown or refueling" operator action statement in Table 3.5.1-1, Process Instrumentation, item 9, column (c). Modify the action statement to ensure the equalization valves and the purge valves are properly addressed in relation to high-range Containment area monitor operability and provide consistency and proper cross-referencing within the Tech Specs.
Add reference to Reactor Building pressure equalization valves to Tech j Spec 3.6.8.
Decrease the required surveillance interval for the Reactor Building equalization valves from 6 months to 3 months in Tech Spec 4.4.1.2.3(d) and (e).
1 Add reference to Reactor Building equalization and add the term "Vent" to Tech i Spec Table 4.22-1, item B. '
Reason for Change 1
By letter dated December 27, 1983, the District provided information to the NRC which enabled the NRC to complete their review concerning the operability 1 of the 12-inch pressure equalization valves. The District demonstrated the ability of the 12-inch pressure equalization valves to close against the buildup of Containment pressure in the event of a DBA.
By letter dated December 4,1984, the NRC issued their SER entitled !
"Demonstration of Containment Purge and Vent Valve Operability." The SER l acknowledged the ability of the 12-inch pressure equalization valves to close during a DBA. In addition, prior to approving the use of the 12-inch pressure 4
equalization valves to equalize Reactor Building pressure during reactor operation (>2% rated power), the NRC required the following two items to be implemented: ,
- 1. Install a high-range monitor on the Reactor Building purge line (Reactor Building stack). Make the monitor opeiational to meet NUREG-0737, Item II.F.1.
i 2. Revise the Rancho Seco Tech Specs. Reduce the leak testing interval for the 12-inch pressure equalization valves from 6 months to 3 months.
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PROPOSED AMENDMENT NO. 130 LOG NO. 649 Safety Analysis PAGE 2 of 8 Item I is complete. Radiation monitor R-15044 has been installed to meet NUREG-0737, Item II.F.1. Proposed Amendment No. 130 meets the NRC requirement stated in item 2 above. In addition to the Tech Spec changes dictated by item 2, other changes are proposed which will properly reference and control Reactor Building equalization at power operation.
The existing "at cold shutdown or refueling" operator action statement in Table 3.5.1-1, item 9, column (c) represents an unnecessary restriction on purging operations. When the plant is in cold shutdown, no condition should be placed on the purge valves with regard to operability of the Reactor Building high-range area radiation monitors. Also, a refueling restriction on the purge valves in Table 3.5.1-1 is unnecessary. Refueling Tech Spec Section 3.8 establishes the refueling requirements for the Reactor Building purge system. Table 3.5.1-1 is designed to apply only during reactor startup and power operation conditions.
Adding reference to Reactor Building equalization isolation in Table 3.5.1-1, Process Instrumentation, item 9 is necessary to establish conditions on Reactor Building equalization operations during reactor power operations.
A new operator action statement is added to Table 3.5.1-1, Process .
Instrumentation, item 9, column (c) to address purging and equalization in l relation to high-range Reactor Building area monitor operability during ractor operation conditions and provide consistency with Tech Spec 3.6.7, 3.6.8, and Table 3.5.5-1.
l The Reactor Building pressure equalization valves are included in Tech Spec l 3.6.8 to complement a Containment integrity requirement which exists on the Reactor Building purge valves. The operability requirements of Table 3.5.1-1 which address both purging and equalization are cross-referenced in Tech Spec 3.6.8. l Tech Spec 4.4.1.2.3(d) is rewritten to address the NRC requirement of a 3-month Reactor Building pressure equalization valve leak rate testing surveillance interval. Tech Spec 4.4.1.2.3(e) it, changed to reflect the same l 3-month surveillance requirement on the equalization valves. d The radioactive gaseous waste sample and analysis requirement of Table 4.22-1 is modified and clarified to include Reactor Building equalization operations specifically, and Reactor Building venting in general, thereby assuring all significant Reactor Building gaseous releases are properly sampled and analyzed prior to commencing the release.
If the Reactor Guilding pressure is negative and a Reactor Building equalization operation is desired, a grab sample analysis shall be required.
For a negative Reactor Building pressure, an equalization operation will cause air outside the Reactor Building to flow into the Containment. To preclude the possibility of an unanalyzed release through the Reactor Building stack )
(e.g., if the Containment pressure should shift from negative to positive during an equalization operation), a grab sample analysis of the Containment atmosphere is required prior to initiation of equalization. I
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PROPOSED AMENDMENT NO. 130 LOG NO. 649 Safety Analysis PAGE 3 of 8 EVALUATION AND BASIS FOR SAFETY FINDINGS Systems. Subsystems. and Components Affected 1
The purge syctem and pressure equalization system are affected by the proposed l changes. A high-range radiation monitor (R-15044) was installed in the l Reactor Building stack to meet the NUREG-0737, Item II.F.1 requirement and an NRC condition on using the equalization valves during reactor power operation.
Safety Functions of Affected Systems /Com_conents The purge system consists of the Reactor Building purge air supply and exhaust units installed outside of the Reactor Building, with penetration ducts, isolation valves and controls. The supply unit consists of a fan, electric heating coil, and pre-filter. The exhaust unit consists of a fan, pre-filter, high efficiency filter, and charcoal filter. Exhaust air is discharged to the atmosphere through the Reactor Building stack and diluted by the addition of outside air. The discharge is monitored by the Reactor Building stack monitor R-15044. The monitor activates an alarm system in the event of excessive
! radioactivity. On a high radiation signal from the Reactor Building stack monitor, the Reactor Building purge fans are automatically tripped, thus terminating a purge vent operation. The fans are operated remotely from the control panel in the Control Room.
The purge system is provided with motor-operated isolation valves inside the Reactor Building and pneumatically activated valves outside the Reactor Building in both the supply and discharge ducts. These valves are closed during reactor operation and will open only for purging during cold shutdown or refueling. The purge valves are operated remotely from the control panel in the Control Room. Testing of the isolation valves is accomplished each l time the purge system is put into operation.
l l The pressure equalization system provides a continuous equalization of l pressures between the Reactor Building interior and the outside environment I through the purge air system. The system consists of a separate penetration l
! to the Reactor Building interior and is connected to the purge system supply l and discharge ducts outside the Reactor Building. The 12-inch diameter l l penetration is equipped with two isolation valves, a motor-operated valve l l inside, and a pneumatically actuated valve outside the Reactor Building. '
! Connections to the purge supply and exhaust ducts are equipped with two check l valves and one pneumatically operated equalizing auxiliary valve (also known as the equalization block valve). The valves function as follows:
A. Under normal operating conditions the purge isolation valves are closed, while the equalizing auxiliary valve (block valve) and the equalizing l
penetration isolation valves are also closed.
l B. When the Reactor Building is under positive pressure, Reactor Building air is allowed to bleed gradually through the equalization valves while the Reactor Building exhaust fan is running. From the equalizing line the
- Reactor Building air flows to the inlet of the purge exhaust filters, then to the Reactor Building stack and radiation monitor, and into the atmosphere.
a PROPOSED AMENDMENT NO. 130 LOG NO. 649 Safety Analysis PAGE 4 of 8 C. When the Reactor Building is under negative pressure the air bleeds into the purge system through the purge supply unit filters and is further conveyed into the building through the pressure equalizing line. In this operating mode the Reactor Building exhaust fan is not running.
D. For the purging operation, the purge isolation valves are opened while all pressure equalization valves and the equalizing auxiliary valves are closed. For the mini-purge operation, the equalizing line is used to slowly purge the Reactor Building.
E. All purge and equalizing isolation valves close automatically on a SFAS signal. Also, the two safety features equalizing valves will isolate on a high Reactor Building high-range area monitor signal.
F. When equalization is in progress, the equalizing block valve will automatically close on a high radiation signal from the Reactor Building stack monitor.
Effect on Safety Functions and Analysis During cold shutdown current Tech Specs can require the purge valves to be closed even though the much larger personnel hatch and equipment hatch are permitted to be open. Purging while in cold shutdown causes air to flow into the Reactor Building through the personnel and/or equipment hatch. Tripping the purge fans and closing the purge valves would terminate air flow out of the Reactor Building through the purge system, but would not block the air path out of the Reactor Building via the equipment and/or personnel hatches.
Thus, the potential exists for an unmonitored and unfiltered release. If the purge valves are allowed to be open at all times with the exhaust fan running during cold shutdown, a constant inflow of air through the equipment and/or personnel hatch can be maintained and an inadvertent airborne radioactive release inside Containment would at worst be filtered and monitored through the purge system and Reactor Building stack. The proposed Tech Spec changes which involve the purge system are designed to assure a monitored and filtered release path for the Containment atmosphere is maintained when Containment integrity is not required (i.e., cold shutdown).
During cold shutdown the Reactor Building stack monitor is controlled by the operability requirements of Tech Spec Table 3.16-1 and is considered the controlling cold shutdown monitor for purging operations. Table 3.5.1-1 is designed to apply during startup and power operation. The Accident Monitoring Table 3.5.5-1 applies only for operating modes above cold shutdown.
Limitations placed on the purge valves during cold shutdown that are based on the operability of the high range Reactor Building area monitors are unnecessary. The proposed Tech Spec changes will ensure that the appropriate cold shutdown requirements on the purge valves are in place.
PROPOSED AMENDNENT NO. 130 LOG N0. 649 Safety Analysis PAGE 5 of 8 During refueling periods Tech Spec Section 3.8 governs the purge system and Reactor Building stack menitor operability requirements. The purge valves and stack monitor are required to be operable during fuel movement. If these requirements are not met, the LC0 stated in Specification 3.8.9 requires movement of fuel to cease. Corrective actions must then be taken before fuel movement can continue. While a purge is in process during refueling, the equalizing line block valve is kept closed.
l The accident analysis of USAR Chapter 14 contains no postulated cold shutdown l accidents in the Reactor Building. The limiting USAR cold shutdown accident with regard to gaseous releases is a fuel handling accident in the Spent Fuel Pool Building. This accident, analyzed in Chapter 14 of the USAR, bounds.a similar accident in the Reactor Building.
The Reactor Building stack monitor has a much lower setpoint than the high range Reactor Building area monitors. If a fuel handling accident should occur in the Reactor Building during refueling, the Reactor Building stack monitor would function to terminate a release through the purge system by shutting off the purge supply and exhaust fans. The high-range Reactor Building area monitors are accident monitors designed to automatically close both the purge and equalization isolation valves to mitigate an accident which
, may occur at power operation. Having a high-range Reactor Building area monitor operability requirement on the purge valves during refueling is i
unnecessary and is unlikely to provide any additional radioactive release protection than is already provided by Tech Spec Section 3.8.
Decreasing the leak test surveillance interval on the equalization valves from
, 6 months to 3 months will give greater assurance that the equalization l isolation valves will provide Containment isolation under accident conditions. Decreasing the surveillance interval meets an NRC requirement for
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allowing equalization at power operation, as stated in the cover letter to the NRC's SER on operability of the 12-inch Containment equalization valves, dated ,
December 4, 1984.
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Failure Modes The changes made in this proposed amendment incorporate proper and reasonable operability requirements for a purge vent operation at cold shutdown and during refueling, and include consideration for Reactor Building equalization at power operation. In the present Tech Specs, purge valves are required to be operable or closed during cold shutdown even though Containment integrity is not required and the much larger Reactor Building equipment and personnel hatches are permitted to be open. This proposed amendment would require the purge valves to be closed only when the plant is above cold shutdown (when Containment integrity is required), or operable or closed when refueling operations are under way inside Containment. The probability that radioactive gases may escape from the Reactor Building is not affected by this proposed amendment.
PROPOSED AMENDMENT NO. 130 ~ LOG NO. 649 Safety Analysis PAGE 6 of 8 Reactor Building equalization is part of Rancho Seco's original Design Basis.
The USAR Chapter 14 accident analysis considers Reactor Building equalization system operation at power. The Tech Spec changes proposed provide Reactor Building equalization operating requirements which are designed to adequately control equalization operations. No new failure modes are introduced by this proposed Tech Spec change. Consistency between the various related Tech Specs is provided by this change.
Hardware and Control Room instrumentation are not affected by this proposed Tech Spec amendment.
Summary Tech Spec changes are made which fulfill NRC requirements for allowing Reactor Building pressure equalization at power and provide for adequate control of Reactor Builaing pressure equalization operation at power. In addition, changes are made which alleviate the restrictiveness of purge valve operation during cold shutdown and which maintain a controlled release path through the Containment when Containment integrity is not required. Tech Spec Section 3.8 governs refueling requirements on the purge system and adequately controls refueling operations. The probability that radioactive gases may escape from the Reactor Building is not affected by this proposed amendment. No new failure modes are introduced by the proposed changes.
UNREVIEHED SAFETY QUESTION DETERMINATION
- "The probability of occurrence or the consequences of an accident or malfunction of equipment important to safety previously evaluated in the SAR will not be increased because. . ."
The Containment purge valves will not be required to be closed during cold shutdown when the high-range area monitors are inoperabia and Containment integrity is not required. The maximum radiological condition which is analyzed and postulated to occur in the Reactor Building during cold shutdown or refueling is not expected to trip the high-range Reactor Building area monitors. The Reactor. Building stack monitor is the controlling cold shutdown and refueling monitor. This proposed amendment reduces the potential for an unmonitored, unfiltered release when Containment integrity is not required.
Tech Spec Section 3.8 adequately controls purge system operating and monitoring requirements during refueling operations.
Reactor Building pressure equalization at power operation is part of the plant's Licensing Design Basis. The USAR accident analysis considers Reactor Building pressure equalization operation.
- "The possibility for an accident or malfunction of a different type than any evaluated previously in the SAR will not be created because. . ."
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PROPOSED AMENDMENT NO. 130 LOG NO. 649 Safety Analysis PAGE 7 of 8 The Containment purge valves are required to be closed during power operation.
When the plant is in cold shutdown and Containment integrity is not required, it is advantageous to provide a filtered and monitored pathway through the Reactor Building stack instead of allowing a pathway through the equipment and/or personnel hatch. This proposed amendment does not reduce the actions required during startup and power operation modes, and does not change the refueling requirements provided in Tech Spec Section 3.8.
Reactor Building pressure equalization at power operation is part of the plant's Licensing Design Basis. The USAR accioent analysis considers Reactor Building pressure equalization operation.
- "The margin of safety as defined in the basis for any technical specification is not reduced because. . ."
The proposed changes to Tech Spec Sections 3.5.1, 3.6.8, 4.4.1.2.3 and 4.22 do not adversely impact the provisions stated in the bases to the affected Tech Spec sections.
Based on the above discussion, Proposed Amendment No.130 does not involve an Unreviewed Safety Question.
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PROPOSED AMENDHENT NO. 130 LOG NO. 649 l Safety Analysis PAGE 8 of 8 l
! NO SIGNIFICANT HAZARDS CONSIDERATION l
I l The District has reviewed the proposed changes against each of the criterion l
of 10 CFR 50.92, and based on the discussion in the above safety analysis the District has concluded that:
- A significant increase in the probability or consequences of an accident previously evaluated in the SAR will.not be created because. . .
! Containment integrity will be maintained during those ti u s when it is l required by the Tech Specs. Reactor Building pressure equalization at power operation is considered in the accident analysis of the SAR.
- The proposed amendment will not create the possibility of a new or different type of accident previously evaluated in the SAR because. . .
Requiring the purge valves to be closed during cold shutdown when the high-range Reactor Building area monitors are inoperable and Containment
! integrity is not required allows for the possibility of an unmonitored i unfiltered release through the equipment and/or personnel hatches. Deleting this requirement will remove the possibility of an unmonitored, unfiltered release under the conditions described above. The proposed Tech Spec amendment is clearly bounded by the previous analysis which allows the equipment hatch and/or personnel hatch to be open during cold shutdown.
Providing limitations on Reactor Building pressure equalization operations will ass"re that the SAR accident analyses that consider equalization at power will also remain bounding for pressure equalization operations.
- The proposed amendment will not involve a significant reduction in the margin of safety because. . .
Containment integrity is maintained at all appropriate times, such as during refueling and when above cold shutdown. The changes proposed do not compromise any of the bases to the affected Tech Spec sections.
Based on the above discussion, the District concludes that the proposed changes do not constitute any significant hazard to the public, and in no way endanger the public's health and safety.
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