ML040340494

From kanterella
Jump to navigation Jump to search

Proposed Technical Specifications Change Regarding Deletion of Note Referring to Differences Between Unit 1 and Unit 2 Boron Concentrations
ML040340494
Person / Time
Site: North Anna  Dominion icon.png
Issue date: 01/23/2004
From: Hartz L
Virginia Electric & Power Co (VEPCO)
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
03-586
Download: ML040340494 (28)
v • d • e


Text

VIRGINIA ELECTRIC AND POWER COMPANY RICHMOND, VIRGINIA 23261 January 23, 2004 U.S. Nuclear Regulatory Commission Serial No.03-586 Attention: Document Control Desk NAPS/JHL Washington, D.C. 20555 Docket Nos. 50-338/339 License Nos. NPF-4/7 VIRGINIA ELECTRIC AND POWER COMPANY NORTH ANNA POWER STATION UNITS I AND 2 PROPOSED TECHNICAL SPECIFICATIONS CHANGE DELETION OF NOTE REFERRING TO DIFFERENCES BETWEEN UNIT I AND 2 BORON CONCENTRATIONS Pursuant to 10 CFR 50.90, Virginia Electric and Power Company (Dominion) requests an amendment to Facility Operating License Numbers NPF-4 and NPF-7 in the form of a change to the Technical Specifications for North Anna Power Station Units 1 and 2.

The proposed change revises Surveillance Requirements 3.5.1.4, 3.5.4.3, and 3.6.7.3 to delete a note referring to differences in Units 1 and 2 boron concentrations for the Safety Injection Accumulators, Refueling Water Storage Tank, and Casing Cooling Tank.

A discussion of the proposed change is included in Attachment 1. The Technical Specification marked-up pages that reflect the proposed changes and the Technical Specification pages that incorporate the proposed changes are provided in Attachments 2 and 3, respectively. In addition, Technical Specification Bases changes reflecting the proposed changes are included for information only. The Technical Specification Bases will be revised in accordance with the Technical Specification Bases Control Program, Technical Specification 5.5.13, following NRC approval of the license amendment.

The proposed changes have been reviewed and approved by the Station Nuclear Safety and Operating Committee and the Management Safety Review Committee.

In accordance with the requirements of 10 CFR 50.92, the enclosed application is judged to involve no significant hazards. In addition, the proposed change has been determined to qualify for categorical exclusion from an environmental assessment as AOD

set forth in 10 CFR 51.22(c)(9).

The basis for these determinations is included in.

Once approved the amendment will be implemented within 30 days. Should you have any questions or require additional information, please contact Jay Leberstien at (540) 894-2574.

Very truly yours, Leslie N. Hartz Vice President - Nuclear Engineering Commitments made is this letter: None Attachments:

1. Discussion of Change
2. Mark-up of Technical Specifications
3. Proposed Technical Specifications cc:

U.S. Nuclear Regulatory Commission Region II Sam Nunn Atlanta Federal Center 61 Forsyth Street, SW Suite 23 T85 Atlanta, GA 30303 Mr. M. T. Widmann NRC Senior Resident Inspector North Anna Power Station Commissioner Bureau of Radiological Health 1500 East Main Street Suite 240 Richmond, VA 23218 Mr.

S. R. Monarque Project Manager U. S. Nuclear Regulatory Commission One White Flint North 11555 Rockville Pike Rockville, MD 20852

SN: 03-586 Docket Nos.: 50-338/339

Subject:

Proposed TS Change Deletion of Note Referring to Diff. In Ul & U2 Boron Concentrations COMMONWEALTH OF VIRGINIA

)

)

COUNTY OF HENRICO

)

The foregoing document was acknowledged before me, in and for the County and Commonwealth aforesaid, today by Leslie N. Hartz, who is Vice President - Nuclear Engineering, of Virginia Electric and Power Company. She has affirmed before me that she is duly authorized to execute and file the foregoing document in behalf of that Company, and that the statements in the document are true to the best of her knowledge and belief.

Acknowledged before me this 23rd day of January, 2004.

My Commission Expires: March 31, 2004.

A)

N tary Public S E v

A..

Discussion of Change North Anna Power Station Units 1 and 2 Virginia Electric and Power Company (Dominion)

DISCUSSION OF CHANGES Introduction Pursuant to 10 CFR 50.90, Virginia Electric and Power Company (Dominion) requests an amendment to Facility Operating License Numbers NPF-4 and NPF-7 in the form of changes to the Technical Specifications (TS) for North Anna Power Station Units 1 and

2. The proposed changes are administrative in nature and are requested to delete a note differentiating between Unit 1 and 2 boron concentrations for TS Surveillance Requirements 3.5.1.4, 3.5.4.3, and 3.6.7.3. Further discussion on the reason for the deletion of the note is provided below.

Discussion License Amendment Nos. 225 and 206 dated March 21, 2001 revised the boron concentration limits in the safety injection accumulators, refueling water storage tank (RWST), casing cooling tank, and reactor coolant system during refueling.

Implementation of the amendments was scheduled to be performed on a staggered basis during the Unit 1 Fall 2001 refueling outage and the Unit 2 Fall 2002 refueling outage.

Following the implementation of License Amendment No. 225 for North Anna Unit 1 in Fall 2001 and prior to the implementation of License Amendment No. 206 during the Fall 2002, a conversion to the Improved Technical Specifications (ITS) occurred. This required that a Note be added to TS Surveillance Requirements 3.5.1.4, 3.5.4.3, and 3.6.7.3 to differentiate between Unit 1 and 2 boron concentrations.

License Amendment No. 206 was subsequently implemented during the Unit 2 Fall 2002 refueling outage.

It is requested that a change to TS Surveillance Requirements 3.5.1.4, 3.5.4.3, and 3.6.7.3 be approved in order to delete a Note differentiating between Unit 1 and 2 boron concentrations.

Now that License Amendment Nos. 225 and 206 have been implemented on North Anna Units 1 and 2, there is no longer a need for the note. The proposed changes do not change the operation of the plant.

The changes are administrative in nature.

TS Bases changes, reflecting the proposed changes are included for information only.

The TS Bases will be revised in accordance with the TS Bases Control Program, TS 5.5.13 following NRC approval of.the license amendment.

Proposed Changes TS Surveillance Requirement 3.5.1.4 is to be revised to delete the Note that states:

NOTE----------------------------------

For Unit 2, until the first entry into MODE 4 following the Unit 2 Fall 2002 refueling outage, the accumulator boron concentration acceptance criteria shall be > 2200 ppm and <

2400 ppm.

TS Surveillance Requirement 3.5.4.3 is to be revised to delete the Note that states:

NOTE------------------------------------

For Unit 2, until the first entry into MODE 4 following the Unit 2 Fall 2002 refueling outage, the RWST boron concentration acceptance criteria shall be > 2300 ppm and < 2400 ppm.

TS Surveillance Requirement 3.6.7.3 is to be revised to delete the Note that states:

NOTE ------------------------------------

-NOE For Unit 2, until the first entry into MODE 4 following the Unit 2 Fall 2002 refueling outage, the casing cooling tank boron concentration acceptance criteria shall be > 2300 ppm and < 2400 ppm.

No Significant Hazards Consideration Dominion has evaluated whether or not a significant hazards consideration is involved with the proposed changes by focusing on the three standards set forth in 10 CFR 50.92, Issuance of amendment," as discussed below:

1. Does the proposed license amendment involve a significant increase in the probability or consequences of an accident previously evaluated?

The proposed changes to TS Surveillance Requirements 3.5.1.4, 3.5.4.3, and 3.6.7.3 delete a note that is no longer necessary and do not alter any plant equipment or operating practices in such a manner that the probability of an accident is increased. The proposed changes will not alter assumptions relative to the mitigation of an accident or transient event.

2. Does the proposed license amendment create the possibility of a new or different kind of accident from any accident previously evaluated?

The proposed changes do not involve a physical alteration of the plant (no new or different type of equipment will be installed) or changes in the methods governing normal plant operation. Therefore, the proposed changes do not create the possibility of a new or different kind of accident from any accident previously evaluated.

3. Does the proposed amendment involve a significant reduction in a margin of safety?

The proposed changes do not alter the boron concentrations in the safety injection accumulators, RWST, and casing cooling tank. The proposed changes to TS Surveillance Requirements 3.5.1.4, 3.5.4.3, and 3.6.7.3 are considered administrative in nature. Therefore, the proposed changes do not involve a significant reduction in the margin of safety.

Based on the above, Dominion concludes that the proposed changes do not present a significant hazards consideration under the standards set forth in 10 CFR 50.92(c), and, accordingly, a finding of "no significant hazards consideration" is justified.

Environmental Assessment This amendment request meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9) as follows:

(i)

The amendment involves no significant hazards consideration.

As described above, the proposed changes involve no significant hazards consideration.

(ii)

There is no significant change in the types or significant increase in the amounts of any effluents that may be released offsite.

The proposed changes do not involve the installation of any new equipment, or the modification of any equipment that may affect the types or amounts of effluents that may be released offsite. Therefore, there is no significant change

in the types or significant increase in the amounts of any effluents that may be released offsite.

(iii)

There is no significant increase in individual or cumulative occupation radiation exposure.

The proposed changes do not involve plant physical changes, or introduce any new mode of plant operation. Therefore, there is no significant increase in individual or cumulative occupational radiation exposure.

Based on the above, Dominion concludes that the proposed changes meet the criteria specified in 10 CFR 51.22 for a categorical exclusion from the requirements of 10 CFR 51.22 relative to requiring a specific environmental assessment by the Commission.

Conclusion The proposed changes are administrative in nature. The changes only delete a note in TS Surveillance Requirements 3.5.1.4, 3.5.4.3, and 3.6.7.3 that is no longer applicable.

License Amendments 225 and 206 were implemented in the Fall 2001 for Unit 1 and Fall 2002 for Unit 2 and there is no longer a reason to differentiate between boron concentrations. No changes are being made to the operation of North Anna Units 1 and 2 as a result of the proposed changes.

The Station Nuclear Safety and Operating Committee (SNSOC) and the Management Safety Review Committee (MSRC) have reviewed this proposed change to the Technical Specifications and have concluded that it does not involve a significant hazards consideration and will not endanger the health and safety of the public.

Mark-up of Technical Specifications Change North Anna Power Station Units 1 and 2 Virginia Electric and Power Company (Dominion)

Accumulators 3.5.1 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.5.1.1 Verify each accumulator isolation valve is 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> fully open.

SR 3.5.1.2 Verify borated water volume in each 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> accumulator is 7580 gallons and

< 7756 gallons.

SR 3.5.1.3 Verify nitrogen cover pressure in each 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> accumulator is 599 psig and 667 psig.

SR 3.5.1.4 NO'TE For 4 flowingl the Uit 2 all 202 rc-f weling u ta-ge, the -Accumul ator boron concentration acceptance criteria shall be 2200 ppmf and Wr100 pm Verify-boron concentration in each 31 days accumulator is 2 2500 ppm and 2800 ppm.

AND

.-----NOTE-Only required,.

to be performed for affected accumulators Once within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> after each solution volume increase of 2 50% of indicated level that is not the result of addition from the refueling water storage tank North Anna Units 1 and 2

.3.5.1-2 Amendments 231/212

RWST 3.5.4 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.5.4.1 Verify RWST borated water temperature is 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> 2 400F and 500F.

SR 3.5.4.2 Verify RWST borated water volume is 7 days 2 466,200 gallons and < 487,000 gallons.

SR 3.5.4.3 For Unit 2, until 1

4 th ft ctjr4-rtt refueling outaqe, the I' ST bron concentration acceptan-cri-teria -hal be4 230O ppm and 5 ?400 ppm.

Verify RWST boron concentration is 7 days 2 2600 ppm and 2800 ppm.

North Anna Units 1 and 2 3.5.4-2 Amendments 231/212

RS System RS System 3.6.7 ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME F. One outside RS F.1 Enter LCO 3.0.3.

Immediately subsystem and one inside RS subsystem inoperable and not in the same train.

OR Three or more RS subsystems inoperable.

OR Two outside RS subsystems inoperable.

SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.6:7.1 Verify casing cooling tank temperature is 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />

> 350F and 50F.

SR 3.6.7.2 Verify casing cooling tank contained 7 days borated water volume is 2 116,500 gal.

-SR 3.6.7.3 NOTE

-For-Unit 2 until the first entry ito

--r~ueingoutge, the casing ooling -ank

~hal1bc ~

300 pm "nzII 2400-pm-Verify casing cooling tank boron 7 days concentration is 2 2600 ppm and 2800 ppm.

North Anna Units 1 and 2 3.6.7-2 Amendments 231/212

Accumulators 8 3.5.1 BASES SURVEILLANCE SR 3.5.1.2 and SR 3.5.1.3 REQUIREMENTS (continued)

Every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />, borated water volume and nitrogen cover pressure are verified for each accumulator. This Frequency is sufficient to ensure adequate injection during a LOCA.

Because of the static design of the accumulator, a 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> Frequency usually allows the operator to identify changes before limits are reached. Operating experience has shown this Frequency to be appropriate for early detection and.

correction of off normal trends.

SR 3.5.1.4 The boron concentration should be verified to be within required limits for each accumulator every 31 days since the static design of the accumulators limits the ways in which the concentration 'can be changed. A Note tates that for 0~~m I

HA i

An A-.

Unit 2 nti

-he irst entry into OEIfllwn h U~nit 2 Fall 200 refueligoUtage,. t _gaCC1,M~ihtr_boron ronrentration acceptamIe-&c4-ter4.a s&143iA-e--*.4on-p.4l 2400-pp=_, The 31 day Frequency is adequate to identify changes that could occur from mechanisms such as stratification or inleakage. Sampling the affected accumulator within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> after a 50% increase of indicated level will identify whether inleakage has caused a reduction in boron concentration to below the required limit. It is not necessary to verify boron concentration if the added water inventory is from the refueling water storage tank (RWST),

because the water contained in the RST is within the accumulator boron concentration requirements. This 'is consistent with the-recommendation of NUREG-1366 (Ref. 3).

Although the run of piping between the to accumulator discharge check valves is credited in demonstrating compliance with Technical Specification 3.5.1 minimum accumulator volume requirement, the minimum boron concentration requirement does not apply to this run of piping. Applicable accident analyses have explicitly considered in-leakage from the RCS, and the resulting reduction in boron concentration in this run of piping, which is not sampled.

SR 3.5.1.5 Verification every 31 days that power is removed from each accumulator isolation valve operator when the RCS pressure is 2 2000 psig ensures that an active failure could not (continued)

North Anna Units 1 and 2 B 3.5.1-7 Revision

RWST B 3.5.4 BASES APPLICABLE SAFETY ANALYSES (continued) available volume. The deliverable volume limit is assumed by the Large Break LOCA containment analyses. For the RST, the deliverable volume is different from the total volume contained. Because of the design of the tank, more water can be contained than can be delivered. The upper RST volume limit is assumed for pH control after a LBLOCA. The minimum boron concentration is' an explicit assumption in the main steam line break (MSLB) analysis to ensure'the required shutdown capability. The importance of 'its value is small because of the boron injection tank (BIT).with a high boron concentration. The maximum boron concentration is an explicit assumption in the inadvertent ECCS actuation analysis, although it is typically a nonlimiting event and the results are'very insensitive to boron concentrations.

The maximum RWST temperature ensures that the amount of containment cooling provided from the RWST during containment pressurization events is consistent with safety analysis assumptions. The minimum RWST temperature is an assumption in the inadvertent Quench Spray actuation analyses.

For a large break LOCA analysis, the minimum water volume limit of 466,200 gallons and'the lower boron concentration

'limit of 2600 ppm are used to compute the post LOCA sump boron concentration necessary to assure subcriticality.-F-or-UtJ9 2. ujnti3 the first-entry nto MODE4I following thc-

-Unit 2 Fl3 202 -fueling otage, the min'im S1o~..

tA 2cceptance criteria shall e 20 The large break LOCA is the limiting case since the safety analysis assumes that all control rods are out of the core.

The upper limit on boron concentration of 2800 ppm is used to determine the maximum allowable time to switch 'to' hot leg recirculation following a LOCA. Fr nit 2, ntil the first entry into ME following the Unt-2 all 2002 rfueling outage, the max-im'm RST 'boron concentraticn acceptancs criteria shall be 2400 ppm The purpose of switching from cold leg to hot leg injection is to avoid boron precipitation in the core following the accident.

In the ECCS analysis, the quench spray temperature is

'bounded by the RWST lower temperature limit of 400F. If the lower temperature limit is violated, the quench spray further reduces' containment pressure, which decreases the rate at which steam can be vented out the break and increases peak clad temperature. 'The upper temperature limit of 500F is bounded by the values used in the small break LOCA analysis (continued)

I North Anna Units 1 and 2 B 3.5.4-3 Revision 6

RWST B 3.5.4 BASES SURVEILLANCE SR 3.5.4.2 (continued)

REQUIREMENTS support continued ECCS:and Recirculation Spray System pump operation on recirculation. Since the RWST volume is normally stable and is protected by an alarm, a 7 day Frequency is appropriate and has been shown to be acceptable through operating experience.

SR 3.5.4.3 The boron concentration of the RWST should be verified every 7 days to be within the required limits.-A *ete stntis _lt6u_

.- r Unit 2, unt~j

~he filp-st irte 140DE E folloing the 9nit 2 Fall -200r-ef-Ue41ng-outage, te RWST bo.oAn__

conce ti acetancc criteria hall be Ž!

230ppm asnd a4eppfi--This SR ensures that the reactor will remain subcritical following aLOCA. Further, it assures that the resulting sump pH will be maintained in an acceptable range so that boron precipitation in the core will not occur and the effect of chloride and caustic stress corrosion on mechanical systems and components will be minimized. Since the RIST volume is normally stable, a 7 day sampling Frequency to verify boron concentration is appropriate and has'been shown to be acceptable through operating experience.

REFERENCES

1. UFSAR, Chapter.6 and Chapter 15.

North Anna Units I and 2 B 3.5.4-6 Revision

RS System B 3.6.7 BASES SURVEILLANCE SR 3.6.7.1 (continued)

REQUIREMENTS the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> Frelquency is considered adequate in view of other indications available in the control room, including alarms, to alert the operator to an abnormal condition.

SR 3.6.7.2 Verifying the casing cooliig tank contained borated water volume provides assurance that sufficient water is available to support the outside RS subsystem pumps during the time they are required to operate. The 7 day Frequency of this SR was developed considering operating experience related to the parameter variations and instrument drift during the applicable'MODES. Furthermore, the 7 day Frequency is considered adequate in view.of other indications available in the control room, including alarms, to alert the operator to an abnormal condition.

SR 3.6.7.3 Verifying the boron concentration of the solution in the casing cooling tank provides assurance that borated water added from the casing cooling tank to RS subsystems will not dilute the solution being recirculated in the containment sump.-A Note tatc that-$r-U 2st entry tace - -e Wg-eon~w W

aceperon-eneetrwa-c t ance criterin zH be-a-239-pe--&-24OGpp-The 7 day Frequency of this SR was developed considering the known stability of stored borated water and the low probability of any source of diluting pure'water.

SR 3.6.7.4 Verifying the correct alignment of man'ual, power operated, iand automatic.valves, excluding check valves, in the RS System and casing cooling tank provides assurance that the proper flow path exists for operation of 'the RS System. This iSR does not apply to valves that are locked, sealed, or

,otherwise secured in position, since they are verified as ibeing in the correct position prior to being secured. This SR idoes not require any testing or valve manipulation. Rather, Wit involves verification, through a system walkdown, that

{those valves outside containment and capable of potentially ibeing mispositioned are in the correct-position.

North Anna Units I and'2 B 3.6.7-7 Revision Proposed Technical Specifications Changes North Anna Power Station Units 1 and 2 Virginia Electric and Power Company (Dominion)

Accumul ators 3.5.1 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.5.1.1 Verify each accumulator isolation valve is 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> fully open.

SR 3.5.1.2 Verify borated water volume in each 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> accumulator is 7580 gallons and

  • 7756 gallons.

SR 3.5.1.3 Verify nitrogen cover pressure in each 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> accumulator is 2 599 psig and 667 psig.

SR 3.5.1.4 Verify boron concentration in each 31 days accumulator is 2500 ppm and 2800 ppm.

AND NOTE------

Only required to be performed for affected accumulators Once within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> after each solution volume increase of 50% of indicated level that is not the result of addition from the refueling water storage tank SR 3.5.1.5 Verify power is removed from each 31 days accumulator isolation valve operator when RCS pressure is 2000 psig.

I North Anna Units 1 and 2 3.5.1-2

RWST 3.5.4 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.5.4.1 Verify RWST borated water temperature is 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />

> 400F and 500F.

SR 3.5.4.2 Verify RWST borated water volume is 7 days 2 466,200 gallons and 487,000 gallons.

SR 3.5.4.3 Verify RWST boron concentration is 7 days 2 2600 ppm and < 2800 ppm.

I North Anna Units 1 and 2 3.5.4-2

RS System 3.6.7 ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME F. One outside RS F.1 Enter LCO 3.0.3.

Immediately subsystem and one inside RS subsystem inoperable and not in the same train.

OR Three or more RS subsystems inoperable.

OR Two outside RS subsystems inoperable.

SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.6.7.1 Verify casing cooling tank temperature is 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> 2 350F and 500F.

SR 3.6.7.2 Verify casing cooling tank contained 7 days borated water volume is 116,500 gal.

SR 3.6.7.3 Verify casing cooling tank boron 7 days concentration is 2600 ppm and 2800 ppm.

SR 3.6.7.4 Verify each RS and casing cooling manual, 31 days power operated, and automatic valve in the flow path that is not locked, sealed, or otherwise secured in position is in the correct position.

SR 3.6.7.5 Verify each RS and casing cooling pump's In accordance developed head at the flow test point is with the greater than or equal to the required Inservice developed head.

Testing Program I

North Anna Units 1 and 2 3.6.7-2

RS System 3.6.7 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.6.7.6 Verify on an actual or simulated actuation 18 months signal(s):

a. Each RS automatic valve in the flow path that is not locked, sealed, or otherwise secured in position, actuates to the correct position;
b. Each RS pump starts automatically; and
c. Each casing cooling pump starts automatically.

SR 3.6.7.7 Verify each spray nozzle is unobstructed.

Following maintenance which could cause nozzle blockage North Anna Units 1 and 2 3.6.7-3

Accumulators B 3.5.1 BASES SURVEILLANCE SR 3.5.1.2 and SR 3.5.1.3 REQUIREMENTS (continued)

Every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />, borated water volume and nitrogen cover pressure are verified for each accumulator. This Frequency is sufficient to ensure adequate injection during a LOCA.

Because of the static design of the accumulator, a 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> Frequency usually allows the operator to identify changes before limits are reached. Operating experience has shown this Frequency to be appropriate for early detection and correction of off normal trends.

SR 3.5.1.4 The boron concentration should be verified to be within required limits for each accumulator every 31 days since the static design of the accumulators limits the ways in which the concentration can be changed. The 31 day Frequency is adequate to identify changes that could occur from mechanisms such as stratification or inleakage. Sampling the affected accumulator within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> after a 50% increase of indicated level will identify whether inleakage has caused a reduction in boron concentration to below the required limit. It is not necessary to verify boron concentration if the added water inventory is from the refueling water storage tank (RWST), because the water contained in the RWST is within the accumulator boron concentration requirements.

This is consistent with the recommendation of NUREG-1366 (Ref. 3).

Although the run of piping between the two accumulator discharge check valves is credited in demonstrating compliance with Technical Specification 3.5.1 minimum accumulator volume requirement, the minimum boron concentration requirement does not apply to this run of piping. Applicable accident analyses have explicitly considered in-leakage from the RCS, and the resulting reduction in boron concentration in this run of piping, which is not sampled.

SR 3.5.1.5 Verification every 31 days that power is removed from each accumulator isolation valve operator when the RCS pressure is 2000 psig ensures that an active failure could not result in the closure of an accumulator motor operated isolation valve. If this were to occur, only one accumulator would be available for injection given a single failure (continued)

North Anna Units 1 and 2 B 3.5.1-7

Accumulators B 3.5.1 BASES SURVEILLANCE REQUIREMENTS SR 3.5.1.5 (continued) coincident with a LOCA. Since power is removed under administrative control, the 31 day Frequency will provide adequate assurance that power is removed.

This SR allows power to be supplied to the motor operated isolation valves when RCS pressure is < 2000 psig, thus allowing operational flexibility by avoiding unnecessary delays to manipulate the breakers during unit startups or shutdowns.

REFERENCES

1. UFSAR, Chapter 6 and Chapter 15.
2. 10 CFR 50.46.
3. NUREG-1366, February 1990.

North Anna Units 1 and 2 B 3.5.1-8

RWST B 3.5.4 BASES APPLICABLE SAFETY ANALYSES (continued) available volume. The deliverable volume limit is assumed by the Large Break LOCA containment analyses. For the RWST, the deliverable volume is different from the total volume contained. Because of the design of the tank, more water can be contained than can be delivered. The upper RWST volume limit is assumed for pH control after a LBLOCA. The minimum boron concentration is an explicit assumption in the main steam line break (MSLB) analysis to ensure the required shutdown capability. The importance of its value is small because of the boron injection tank (BIT) with a high boron concentration. The maximum boron concentration is an explicit assumption in the inadvertent ECCS actuation analysis, although it is typically a nonlimiting event and the results are very insensitive to boron concentrations.

The maximum RWST temperature ensures that the amount of containment cooling provided from the RWST during containment pressurization events is consistent with safety analysis assumptions. The minimum RWST temperature is an assumption in the inadvertent Quench Spray actuation analyses.

For a large break LOCA analysis, the minimum water volume limit of 466,200 gallons and the lower boron concentration limit of 2600 ppm are used to compute the post LOCA sump boron concentration necessary to assure subcriticality. The large break LOCA is the limiting case since the safety analysis assumes that all control rods are out of the core.

The upper limit on boron concentration of 2800 ppm is used to determine the maximum allowable time to switch to hot leg recirculation following a LOCA. The purpose of switching from cold leg to hot leg injection is to avoid boron precipitation in the core following the accident.

In the ECCS analysis, the quench spray temperature is bounded by the RWST lower temperature limit of 400F. If the lower temperature limit is violated, the quench spray further reduces containment pressure, which decreases the rate at which steam can be vented out the break and increases peak clad temperature. The upper temperature limit of 500F is bounded by the values used in the small break LOCA analysis and containment OPERABILITY analysis. Exceeding this temperature will result in a higher peak clad temperature, because there is less heat transfer from the core to the injected water for the small break LOCA and higher containment pressures due to reduced quench spray cooling capacity. For the containment response following an MSLB, (continued)

North Anna Units 1 and 2 B 3.5.4-3

RWST B 3.5.4 BASES APPLICABLE the lower limit on boron concentration and the upper limit on SAFETY ANALYSES RWST water temperature are used to maximize the total energy (continued) release to containment.

The RWST satisfies Criterion 3 of 10 CFR 50.36(c)(2)(ii).

LCO The RWST ensures that an adequate supply of borated water is available to cool and depressurize the containment in the event of a Design Basis Accident (DBA), to cool and cover the core in the event of a LOCA, to maintain the reactor subcritical following a DBA, and to ensure adequate level in the containment sump to support ECCS and Recirculation Spray System pump operation in the recirculation mode.

To be considered OPERABLE, the RWST must meet the water volume, boron concentration, and temperature limits established in the SRs.

APPLICABILITY In MODES 1, 2, 3, and 4, RWST OPERABILITY requirements are dictated by ECCS and Quench Spray System OPERABILITY requirements. Since both the ECCS and the Quench Spray System must be OPERABLE in MODES 1, 2, 3, and 4, the RWST must also be OPERABLE to support their operation. Core cooling requirements in MODE 5 are addressed by LCO 3.4.7, "RCS Loops-MODE 5, Loops Filled," and LCO 3.4.8, RCS Loops-MODE 5, Loops Not Filled." MODE 6 core cooling requirements are addressed by LCO 3.9.5, "Residual Heat Removal (RHR) and Coolant Circulation-High Water Level," and LCO 3.9.6, "Residual Heat Removal (RHR) and Coolant Circulation-Low Water Level."

ACTIONS A.1 With RWST boron concentration or borated water temperature not within limits, they must be returned to within limits within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />. Under these conditions neither the ECCS nor the Quench Spray System can perform its design function.

Therefore, prompt action must be taken to restore the tank to OPERABLE condition. The 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> limit to restore the RWST temperature or boron concentration to within limits was developed considering the time required to change either the boron concentration or temperature and the fact that the contents of the tank are still available for injection.

North Anna Units 1 and 2 B 3.5.4-4

RWST B 3.5.4 BASES ACTIONS B.1 (continued)

With the RWST inoperable for reasons other than Condition A (e.g., water volume), it must be restored to OPERABLE status within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />.

In this Condition, neither the ECCS nor the Quench Spray System can perform its design function. Therefore, prompt action must be taken to restore the tank to OPERABLE status or to place the unit in a MODE in which the RWST is not required. The short time limit of 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> to restore the RWST to OPERABLE status is based on this condition simultaneously affecting redundant trains.

C.1 and C.2 If the RWST cannot be returned to OPERABLE status within the associated Completion Time, the unit must be brought to a MODE in which the LCO does not apply. To achieve this status, the unit must be brought to at least MODE 3 within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and to MODE 5 within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />. The allowed Completion Times are reasonable, based on operating experience, to reach the required unit conditions from full power conditions in an orderly manner and without challenging unit systems.

SURVEILLANCE SR 3.5.4.1 REQUIREMENTS The RWST borated water temperature should be verified every 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> to be within the limits assumed in the accident analyses band. This Frequency is sufficient to identify a temperature change that would approach either limit and has been shown to be acceptable through operating experience.

SR 3.5.4.2 The RWST water volume should be verified every 7 days to be above the required minimum level in order to ensure that a sufficient initial supply is available for injection and to support continued ECCS and Recirculation Spray System pump operation on recirculation. Since the RWST volume is normally stable and is protected by an alarm, a 7 day Frequency is appropriate and has been shown to be acceptable through operating experience.

North Anna Units 1 and 2 B 3.5.4-5

RWST B 3.5.4 BASES SURVEILLANCE REQUIREMENTS (continued)

SR 3.5.4.3 The boron concentration of the RWST should be verified every 7 days to be within the required limits. This SR ensures that the reactor will remain subcritical following a LOCA.

Further, it assures that the resulting sump pH will be maintained in an acceptable range so that boron precipitation in the core will not occur and the effect of chloride and caustic stress corrosion on mechanical systems and components will be minimized. Since the RWST volume is normally stable, a 7 day sampling Frequency to verify boron concentration is appropriate and has been shown to be acceptable through operating experience.

I REFERENCES

1. UFSAR, Chapter 6 and Chapter 15.

North Anna Units 1 and 2 B 3.5.4-6

RS System B 3.6.7 BASES SURVEILLANCE SR 3.6.7.1 (continued)

REQUIREMENTS the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> Frequency is considered adequate in view of other indications available in the control room, including alarms, to alert the operator to an abnormal condition.

SR 3.6.7.2 Verifying the casing cooling tank contained borated water volume provides assurance that sufficient water is available to support the outside RS subsystem pumps during the time they are required to operate. The 7 day Frequency of this SR was developed considering operating experience related to the parameter variations and instrument drift during the applicable MODES. Furthermore, the 7 day Frequency is considered adequate in view of other indications available in the control room, including alarms, to alert the operator to an abnormal condition.

SR 3.6.7.3 Verifying the boron concentration of the solution in the casing cooling tank provides assurance that borated water added from the casing cooling tank to RS subsystems will not dilute the solution being recirculated in the containment sump. The 7 day Frequency of this SR was developed considering the known stability of stored borated water and the low probability of any source of diluting pure water.

SR 3.6.7.4 Verifying the correct alignment of manual, power operated, and automatic valves, excluding check valves, in the RS System and casing cooling tank provides assurance that the proper flow path exists for operation of the RS System. This SR does not apply to valves that are locked, sealed, or otherwise secured in position, since they are verified as being in the correct position prior to being secured. This SR does not require any testing or valve manipulation. Rather, it involves verification, through a system walkdown, that those valves outside containment and capable of potentially being mispositioned are in the correct position.

North Anna Units 1 and 2 B 3.6.7-7

Retrieved from "https://kanterella.com/w/index.php?title=ML040340494&oldid=5407143"