ML20115E832
| ML20115E832 | |
| Person / Time | |
|---|---|
| Site: | Salem  |
| Issue date: | 07/10/1996 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20115E829 | List: |
| References | |
| NUDOCS 9607160249 | |
| Download: ML20115E832 (7) | |
Text
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. 4 UNITED STATES s$
j NUCLEAR REGULATORY COMMISSION e
WASHINGTON, D.C. 20066 4001
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.165TO FACILITY OPERATING LICENSE NO. DPR-75 i
PUBLIC SERVICE ELECTRIC & GAS COMPANY l
PHILADELPHIA ELECTRIC COMPANY-DELMARVA POWER AND LIGHT COMPANY ATLANTIC CITY ELECTRIC COMPANY l
SALEM NUCLEAR GENERATING STATION. UNIT NO. 2 DOCKET NO. 50-311
1.0 INTRODUCTION
i By letter dated May 7, 1996, as supplemented June 14, 1996, the Public Service l
Electric & Gas Company (the licensee) submitted a request for changes to the i
Salem Nuclear Generating Station, Unit No. 2, Technical _ Specifications (TS).
The request would make a one-time change to TS 3/4.7.6, " Control Room i
i Emergency Air Conditioning System," which would permit refueling of Unit 2 with the Control Room Emergency Air Conditioning System (CREACS) inoperable in Modes 5 and 6.
This change will expire after the completion of the Control.
Room and CREACS upgrade, currently in progress, and the restart and entry into Mode 4 of Unit 2 from the current outage.
The June 14, 1996, letter provided clarifying information that did not change the initial proposed no significant hazards consideration determination or the Federal Reaister notice.
2.0 BACKGROUND
The control area air conditioning system (CAACS) is designed to maintain control room temperatures within the limits required for operation, maintenance, and testing of plant controls, and to provide uninterrupted safe j
t occupancy during post-accident conditions. A portion of the CAACS, designated the' CREACS, supplies cooled, filtered air to the control rooms for both units.
L The CREACS is a safety-related system that maintains the habitability of the l
control room in the event of an accident and is isolated during normal operation.
The CREACS was originally designed with two separate trains, each serving one i
plant unit control room. The Unit-1 CREACS serves the control' room and i
adjacent offices for Unit 1 and the corridor between the Unit I and Unit 2 l
control room.
The Unit 2 CREACS serves the control room for Unit 2 only.
Each train consists of a filter enclosure equipped with low efficiency, high-i f
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- 4 efficiency particulate air (HEPA) and charcoal filters, a cooling coil,.two vane-axial fans (one standby), supply and return ducts to the control room, and dampers.
In 1991, the licensee evaluated the leaktight integrity of the wall which separates the two control rooms and determined that the two control rooms should be redesigned into a combined control room with a common envelope. The control room envelope (CRE) that combines both control room areas would be supplied by both CREACS trains. Therefore, the licensee proposed to combine the Unit I and Unit 2 control rooms into a common CRE and modify the CREACS design to provide the capability to serve a CRE that includes both the control rooms.. During the CREACS modification, the CAACS from either unit.is-available and functional to maintain the CRE temperature and habitability.
3.0. EVALUATION The current TS 3/4.7.6 for Modes 5 and 6 requires that:
With less than the full complement of CREACS components operable, restore the inoperable components to operable or initiate and maintain operation of the CREACS in the recirculation mode.
With both fans, the cooling coil, or the filter train inoperable, or with less than two operable isolation dampers in each outside air intake duct, suspend all operations involving core alterations or positive reactivity
. changes.
The 1tcensee proposes to add a note in TS 3/4.7.6 to state that:
i Modes 5 and 6 are excluded from the specification's applicability until entry into Mode 4 following startup from the current 1996 extended outage.
The specification's applicability.will return to all modes following entry into Mode 4.
To make room for this note on page 3/4 7-15, some of the information on this page was relocated to the next page, 3/4 7-16..
The control room temperature is normally maintained at 76 "F with 50% relative humidity. The acceptable upper temperature limit for the CRE is 85 'F which is required to protect instrument accuracy.
The equipment in the CRE has been designed to withstand a temperature of 110 'F without loss of safety function.
The CAACS was designed to maintain CRE ambient temperatures within the comfort level for control room personnel during normal operation. With the CREACS inoperable in Modes 5 and 6, the licensee proposed to use the CAACS to control ambient air temperature and maintain habitability of the CRE during normal and accident conditions.
The licensee has evaluated the functional capability of the CAACS to ensure its operation during Modes 5 and 6 with the CREACS under modification. The licensee ~ stated that the temperature level in the control room will be monitored constantly to ensure that the CRE temperature stays under the
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. acceptable limit of 85 'F.
Should the temperature in the CRE exceed 85 *F, administrative controls will be in place to restore the temperature to within acceptable levels and to prevent any core alteration activities or positive reactivity changes until the acceptable temperature level is restored.
Normally, following an accident, the CAACS will shift to the CREACS in a recirculation mode to protect control room operators from airborne radiation, toxic fumes, hazardous chemicals, and smoke from external fires while the outside air supply is shut off. The CAACS will operate in a recirculation mode for areas outside the CRE. The postulated events for Salem 2 during Modes 5 and 6 are fuel handling accidents, waste gas releases, liquid waste releases, and loss of off-site power. The licensee has justified the one-time TS changes by evaluating these events.
The proposed one-time change necessitated a reassessment of the radiological consequences of postulated fuel handling accidents (FHAs) at Salem Units 1 and 2 while the CREACSs for both units are out of service during the ongoing system upgrade.
Fuel movement inside the fuel handling building (FHB) is restricted in accordance with plant TSs unless FHB ventilation is operable.
However, the licensee's calculations performed as part of the engineering evaluation for an FHA assumed that no credit was taken for the iodine removal by filtration. No credit was taken for prompt radiation detection and isolation of containment building penetrations as required by the TSs. The fuel to be reloaded into the Salem Unit 2 core has decayed for approximately 10 months.
The licensee assumed that the fuel to be reloaded has decayed for 6 months.
The licensee's doses are well within General Design Criterion (GDC) 19.
The staff has completed its evaluation of the potential radiological consequences of an FHA at Salem Unit 2 based upon the conditions of the proposed TS changes.
In addition to reviewing the licensee's submittal, the staff performed an independent analysis to determine plant conformance with the requirements of 10 CFR Part 100 and GDC 19 of Appendix A to 10 CFR Part 50.
In its analysis, the staff utilized the assumptions contained in Regulatory Guide 1.25, and the review procedures specified in Standard Review Plan (SRP) Section 15.7.4.
The staff assumed an instantaneous puff release of noble gases and radioiodine from the gap and plenum of the broken fuel rods.
These gas bubbles will pass through at least 23 feet of water covering the fuel before reaching the containment atmosphere. All airborne activity reaching the containment atmosphere is assumed to exhaust to the environment within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />. As stipulated in the proposed TSs the gap activity is assumed to have decayed for a period of 6 months (4380 hours0.0507 days <br />1.217 hours <br />0.00724 weeks <br />0.00167 months <br />).
The staff computed the offsite doses for Salem 2 using the assumptions described above and NRC's ACTICODE computer code. The resulting calculated values and assumptions are in Tables 1 and 2.
Other accident scenarios that were evaluated are the waste gas releases and liquid waste releases.
Calculations indicated that CREACS is not needed to provide protection against postulated waste gas decay tank or volume control tank ruptures.
The liquid waste, particularly with the decay period since
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plant operation, will cause an airborne radiation problem of sufficient magnitude to threaten control room envelope habitability.
Table 1*
l EAB (rem)
Licensee Staff thyroid dose 7.52 E-5 3.6 E-4 whole body gamma dose 1.86 E-3 4.6 E-4
- The calculations indicate the doses are negligible compared to GDC 19 limits (30 rem and 5 rem respectively)
The licensee evaluated the system in the event of a loss of offsite power (LOOP).
The CAACS is powered from Class lE vital buses and its functional capability will not be interrupted because of LOOP.
The licensee evaluated the system in the event of a potential uncontrolled j
boron dilution during refueling operations and indicated that the CRE habitability will not be impacted as a result of an uncontrolled boron dilution event.
The licensee evaluated the system in the event of a loss of spent fuel pool 4
cooling based on the amount of time the present spent fuel has decayed. The TSs require that the maximum temperature of the pool should not exceed 182 'F when a complete loss of forced cooling occurs. The existing procedures for operator actions under these conditions include:
provide up to 15 gpm of make-up water and j
a operating at least one FHB exhaust fan.
Both of these operator actions can be accomplished from outside of the control room if necessary.
The licensee stated that if both FHB fans are lost, the pool temperatures will increase gradually for approximately two days before ventilation is needed to remove moisture from the FHB atmosphere. Thi: n uld allow sufficient time to restore ventilation to the pool area.
The licensee evaluated the system in the event of a fire inside the control room. The licensee stated that the CRE would be purged by the CAACS during a fire.
Should a fire occur, existing evacuation plans and procedures will be followed to ensure that the plant maintains a safe shutdown condition via local operation of equipment.
If an external fire is detected, operator action will be taken to isolate the CRE from outside air and the CAACS would remain available.
In case the CRE would become uninhabitable due to smoke in the atmosphere, evacuation procedures would be followed as in the case of the internal fire.
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. TABLE 2 l'
l ASSUMPTIONS USED FOR CALCULATING RADIOLOGICAL CONSE0VENCES Parameters Quantity Power Level (Mwt) 3570 Number of Fuel Rods Damaged 204 l
Total Number of Fuel Rods 29,372 l-Shutdown time, hours 4320 Power Peaking Factor
- 1.65 Fission Product Release Duration 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> l
Release Fractions
- l Iodine 12%
l Noble Gases 10%
Krypton Gas 30%
Iodine Forms
- l Elemental 75%
Organic 25%
Core Fission Product Inventories per TID-14844 I
Receptor Point Variables Control Room Atmospheric Relative Concentration, X/Q (sec/m )
4.4 x 10-3 3
3 Control Room Volume, cubic feet 4.1 x 10
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j The licensee evaluated the system in the event of loss of decay heat removal i
by implementing procedural and hardware enhancements to address NRC Generic 1
Letter'88-17. Generic Letter 88-17 requires all licensees to, among other i
things, evaluate the event involvi,ng loss of decay heat removal during nonpower operation and provide compensatory measures to enhance the level of protection. The licensee stated that the fuel has decayed to such low levels in more than 6 months that doses assoc'iated with the fuel handling accident are well below the limits of GDC 19.
The control room has adequate monitoring 4
j capability and procedural guidance to identify and respond to a loss of the residual heat removal system. Also, the CREACS is not required in Modes 5 or i.
6 to mitigate the conrequences of such an accident.
The licensee also evaluated the impact on Salem 2 as a result of a postulated LOCA, fuel handling accident, or gaseous radwaste releases at the Hope Creek plant, which is on the same site as the Salem plant. The analyses indicated that doses to Salem control room personnel will not exceed GDC 19 limits. The licensee stated that the Salem plant will either isolate its CAACS outside air intakes or maintain the capability of being isolated in the event of a Hope i
Creek LOCA.
The' licensee evaluated the impact on CRE habitability from the storage of hazardous chemicals at both Salem and Hope Creek sites. The one possible event which might impact the CRE would be the rupture of an ammonium hydroxide tanker. The licensee stated that no ammonium hydroxide tanker deliveries will be a110wed during the CREACS modification.
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The licensee also evaluated the toxic accumulation of other hazardous i
chemicals with respect to chemical dispersion, high toxicity threshold, or l
container size. The evaluation includes the nitrogen tube trailers and i
replacement refrigerant for the Hope Creek chillers. The analyses indicated-5 that the accumulation of toxic levels for these chemicals in the CRE would not i
3 exceed Regulatory Guide 1.78 limits.
4.0
SUMMARY
The staff has reviewed the licensee's submittal for a one-time TS change to i
permit refueling of Salem 2 with the CREACS inoperable in Modes 5 and 6.
The licensee has justified the use of CAACS to maintain control room envelope ambient temperature and habitability during accident conditions.
The licensee also performed safety analyses and evaluations for postulated events during the refueling period.
Based on this review, the staff concludes that the proposed one-time TS change is acceptable on the basis that:
the proposed changes are justified by the licensee with technical bases that have been reviewed by the staff.
the licensee has evaluated the functional capability and availability of
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the CAACS to maintain the current control room ambient temperature and habitability while the CREACS is inoperable.
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a the licensee's analysis and the staff's independent analysis of the fuel handling accident have indicated that the calculated radiation doses at the CAACS intakes are within the GDC 19 limits.
The licensee has evaluated other postulated events and indicated that their impact on the plant. safety is either under control or insignificant.
Based on the above, the staff has approved the proposed one-time change to TS 3.7.6 for Salem 2.
This approval is intended to be in effect until restart of the plant before entering Mode 4.
5.0 STATE CONSULTATION
In accordance with the Commission's regulations, the New Jersey State official was notified of the proposed issuance of the amendment.
By letter dated Jane 10, 1996, the State official provided several comments.
The State official had subsequent discussions with the licensee regarding these comments.
By telephone call on June 28, 1996, the State official told the NRC that his comments had been resolved.
6.0 ENVIRONMENTAL CONSIDERATION
l The amendment changes a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20. The NRC staff has determined that the amendment involves no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite, and that thes e is no significant increase in individual or cumulative occupational radiation exposure.
The Commission has previously issued a proposed finding that the amendment involves no significant hazards consideration, and there has been no public comment on such finding (61 FR 25710). Accordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
Pursuant to 10 CFR 51.22(b) no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendment.
7.0 CONCLUSION
The Commission has concluded, based on the considerations discussed above, that:
(1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributors:
J. Guo J. Minns Date:
July 10, 1996