ML20149J349

From kanterella
Jump to navigation Jump to search
Proposed TS 3/4.7.1.6 Re SG Atmospheric Relief Bypass Valve Lines
ML20149J349
Person / Time
Site: Millstone Dominion icon.png
Issue date: 07/18/1997
From:
NORTHEAST NUCLEAR ENERGY CO.
To:
Shared Package
ML20149J347 List:
References
NUDOCS 9707280177
Download: ML20149J349 (16)
v • d • e


Text

....

.i

~

Docket No. 50-423 B16550

'l

+

l l

Millstone Nuclear Power Station Unit No. 3 Proposed Revision to Technical Specification Steam Generator Atmospheric Relief Bvoass Valve Lines (PTSCR 3-27-97)

Marked Up Paaes July 1997

[k YD 0

I i

i

'U.S. Nucl::ar Regulatory Commission B16550\\ Attachment 2\\Page 1 MARKUP OF PROPOSED REVISION Refer to the attached markup of the proposed revision to the Technical Specifications.

The attached markup reflects the currently issued version of the Technical Specifications listed below. Pending Technical Specification revisions or Technical Specification revisions issued subsequent to this submittal are not reflected in the enclosed markup.

1 The following Technical Specification changes are included in the attached markup:

A new Technical Specification is proposed. NUREG 1431, Rev.1 is used as the model; with some plant specific format modifications, and with the exception of specifying associated main steam atospheric relief valve isolation (block) valve position.

3/4 7.1.6 A new Technical Specification Bases is proposed. Applicable portions of NUREG 1431, Rev.1, Bases are used or referenced.

83/4.7.1.6 l

i

PLANT SYSTEMS STEAM GENERATOR ATMOSPHERIC RELIEF BYPASS LINE1 LINITING CONDITION FOR OPERATION 3.7.1.6 Each steam generator atmospheric relief bypass valve (SGARBV) line shall be OPERABLE, with the associated main steam atmospheric relief isolation (block) valve in the open position.

APPLICABILITY: MODES 1, 2, and 3, MODE 4 when steam generator is relied upon for heat removal.

ACTIONS a.

With one required SGARBV line inoperable, restore required SGARBV line to OPERABLE status within 7 days or be in at least MODE 3 within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and be in MODE 4 without reliance upon steam generator for heat removal within the next 18 hours2.083333e-4 days <br />0.005 hours <br />2.97619e-5 weeks <br />6.849e-6 months <br />.

LC0 3.0.4 is not applicable, b.

With two or more required SGARBV lines inoperable, restore all but one required SGARBV line to OPERABLE status within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> or be in at least MODE 3 within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and be in MODE 4 without reliance upon steam generator for heat removal within the next 18 hours2.083333e-4 days <br />0.005 hours <br />2.97619e-5 weeks <br />6.849e-6 months <br />.

SURVEILLANCE REQUIRENENTS 4.7.1.6.1 Verify one complete cycle of each SGARBV every 18 months.

4.7.1.6.2 Verify one complete cycle of each main steam atmospheric relief isolation (block) valve every 18 months.

I i

5J '7A C,E%

s

)

l 4

MILLSTONE - UNIT 3 3/4 7-9a Amendment No.

osu

  • PLANT SYSTEMS April 10, 1997 BASES J

SURVEILLANCE REOUIREMENTS (continued) to Specification 4.0.4 would also allow the MSIVs to be cycled to demonstrate post repair OPERABILITY. Action requirements shall not apply until OPERA 8ILITY has been verified.

In addition, if the closure time of the MSIV is less than lo seconds when verified in accordance with Specification 4.7.1.5.2, the OPERABILITY demonstration of the MSIV in MODES 1, 2, or 3 is not required per Specification 4.7.1.5.1.

4.7.1.5.2 This surveillance verifies that MSly closure time is less than 120 seconds on an actual or simulated actuation signal in MODE 4 when tested j

pursuant to Specification 4.0.5.

A simulated signal is defined as any of the following engineered safety features actuation system instrumentation 4

i functional units per Technical Specification Table 4.3-2:

4.a.1) manual initiation, individual, 4.a.2) manual initiation, system, 4.c. containment 4

pressure high-2, 4.d. steam line pressure low, and 4.e. steam line pressure -

negative rate high. This MSIV closure time is assumed in the analyses. This surveillance is normally performed upon returning the plant to operation following a refueling outage. The test is conducted in MODE 4 with the plant at suitable (appropriate) conditions (e.g., pressure and temperature). This 3

surveillance requirement is modified by an exception which allows a delay of 1

testing until MODE 4, to establish conditions consistent with those under which the acceptance criterion was generated. This exception to Specification

-4.0.4 would also allow the MSIVs to be cycled to demonstrate post repair OPERABILITY. Action requirements shall not apply until OPERABILITY has been

. (

verified.

3/4.7.2 STEAM GENERATOR PRES $URE/ TEMPERATURE LIMITATION The limitation on steam generator pressure and temperature ensures that the pressure-induced strecses in the steam generators do not exceed the maximum allowable fracture toughness stress limits. The limitations of 70'F and 200 psig are based on a steam generator RTuor of 60*F and are sufficient to prevent brittle fracture.

3/4.7.3 REACTOR PLANT COMPONENT COOLING WATER SYSTEM The OPERABILITY of the Reactor Plant Component Cooling Water System ensures that sufficient cooling capacity is available for continued operation of safety related equipment tiuring normal and accident conditions.

The redundant cooling capacity of this system, assuming a single failure, is consistent with the assumptions used in the safety analyses.

l 3/4.7.4 SERVICE WATER SYSTEM The OPERABILITY of the Service Water System ensures that sufficient cooling. capacity is available for continued operation of safety-related equip-ment during normal and accident conditions.

The redundant cooling capacity of this system, assuming a single failure, is consistent with the assumptions l(

used in the safety analyses.

NILLSTONE - UNIT 3 8 3/4 7-7 Amendment No. 136 Ndf

~ _. _. _

d i

INSERT A

\\,

3/4.7.1.6 STEAM GENERATOR ATMOSPHERIC RELIEF BYPASS LINES

~

The OPERABILITY of the steam generator atmospheric relief bypass valve (SGARBV) lines provides a method to recover from a steam generator tube rupture (SGTR) event during which the operator is required to perform a limited.cooldown to establish adequate subcooling as a necessary step to limit the primary to secondary break flow into the ruptured steam generator. The 1

time required to limit the primary to secondary break flow for an SGTR event is more critical than the time required to cooldown to RHR entry conditions.

Because of these time constraints, these valves and associated flow paths must be OPERABLE from the control room. The number of SGARBVs required to be 4

OPERABLE from the control room to satisfy the SGTR accident analysis requires consideration of single failure criteria.

Four SGARBV are required to be OPERABLE to ensure the credited steam release pathways available to conduct a unit cooldown following a SGTR.

2 For other design events, the SGARBVs provide a safety grade method for cooling the unit to residual heat removal (RHR) entry conditions should the preferred heat sink via the steam bypass system or the steam generator atmospheric relief valves be unavailable.

Prior to operator action to cooldown, the main steam safety valves (MSSVs) are assumed to operate automatically to relieve steam and maintain the steam generator pressure below design limits.

1 l

Each SGARBV line consists of one SGARBV and an associated block valve (main steam atmospheric relief isolation valve, 3 MSS *MOV18A/B/C/D).

These block valves are used in the event a steam generator atmospheric relief valve (SGARV) or SGARBV fails to close.

Because of the electrical power relationship between the SGARBV and the block valves, if a block valve is i

maintained closed, the SGARBV flow path is inoperable because of single i

failure consideration.

The bases for the required actions can be found in NUREG 1431, Rev. 1.

The LC0 APPLICABILITY and ACTION statements uses the terms " MODE 4 when steam generator is relied upon for heat removal" and "in MODE 4 without reliance upon steam generator for heat removal." This means that those steam generators which are credited for decay heat removal to comply with LC0 3.4.1.3 (Reactor Coolant System, Hot Shutdown) shall have an OPERABLE SGARBV line.

See Bases Section 3/4.4.1'for more detail.

i 4

c..

.w..

n.

,o,--

.' i Docket No. 50-423 B16550 1

(

f Millstone Nuclear Power Station Unit No. 3 Proposed Revision to Technical Specification Steam Generator Atmospheric Relief Bvoass Valve Lines (PTSCR 3-27-97)

Retvoed Paaes l

J July 1997

l U.S. Nucl::ar Regulatory Commission B16550%ttachment 3\\Page 1 RETYPE OF PROPOSED REVISION Refer to the attached retype of the proposed revision to the Technical Specifications.

The attached retype reflects the currently issued version of the Technical Specifications. Pending Technical Specification revisions or Technical Specification revisions issued subsequent to this submittal are not reflected in the enclosed retype.

The enclosed retype should be checked for continuity with Technical Specifications prior to issuance.

1 1

I

PLANT SYSTEMS STEAM GENERATOR ATMOSPHERIC RELIEF BYPASS LINES LIMITING CONDITION FOR OPERATION 3.7.1.6 Each steam generator atmospheric relief bypass valve (SGARBV) line shall be OPERABLE, with the associated main steam atmospheric relief isolation (block) valve in the open position.

APPLICABILITY: MODES 1, 2, and 3, MODE 4 when steam generator is relied upon for heat removal.

ACTIONS a.

With one required SGARBV line inoperable, restore required SGARBV line to OPERABLE status within 7 days or be in at least MODE 3 within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and be in MODE 4 without reliance upon steam generator for heat 1

removal within the next 18 hours2.083333e-4 days <br />0.005 hours <br />2.97619e-5 weeks <br />6.849e-6 months <br />.

LC0 3.0.4 is not applicable.

i b.

With two or more required SGARBV lines inoperable, restore all but one required SGARBV line to OPERABLE status within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> or be in at least MODE 3 within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and be in MODE 4 without reliance upon steam generator for heat removal within the next 18 hours2.083333e-4 days <br />0.005 hours <br />2.97619e-5 weeks <br />6.849e-6 months <br />.

SURVEILLANCE REQUIREMENTS 4.7.1.6.1 Verify one complete cycle of each SGARBV every 18 months.

4.7.1.6.2 Verify one complete cycle of each main steam atmospheric relief isolation (block) valve every 18 months.

1 NILLSTONE - UNIT 3 3/4 7-9a Amendment No.

d 06MB I

ELANT SYSTEMS BASES 1

SURVEILLANCE RE0VIREMENTS (continued) to Specification 4.0.4 would also allow the MSIVs to be cycled to demonstrate post repair OPERABILITY. Action requirements shall not apply until OPERABILITY has been verified.

In addition, if the closure time of the MSIV

)

is less than 10 seconds when verified in accordance with Specification 4.7.1.5.2, the OPERABILITY demonstration of the MSIV in MODES 1, 2, or 3 is not required per Specification 4.7.1.5.1.

4.7.1.5.2 This surveillance verifies that MSIV closure time is less than 120 seconds on an actual or simulated actuation signal in MODE 4 when tested pursuant to Specification 4.0.5.

A simulated signal is defined as any of the following engineered safety features actuation system instrumentation functional units per Technical Specification Table 4.3-2:

4.a.1) manual initiation, individual, 4.a.2) manual initiation, system, 4.c. containment pressure high-2, 4.d. steam line pressure low, and 4.e. steam line pressure -

negative rate high. This MSIV closure time is assumed in the analyses. This surveillance is normally performed upon returning the plant to operation following a refueling outage. The test is conducted in MODE 4 with the plant at suitable (appropriate) conditions (e.g., pressure and temperature).

This surveillance requirement is modified by an exception which allows a delay of testing until MODE 4, to establish conditions consistent with those under which the acceptance criterion was generated. This exception to Specification 4.0.4 would also allow the MSIVs to be cycled to demonstrate post repair OPERABILITY. Action requirements shall not apply until 0PERABILITY has been verified.

3/4.7.1.6 STEAM GENERATOR ATMOSPHERIC RELIEF BYPASS LINES The OPERABILITY of the steam generator atmospheric relief bypass valve (SGARBV) lines provides a method to recover from a steam generator tube rupture (SGTR) event during which the operator is required to perform a limited cooldown to establish adequate subcooling as a necessary step to limit the primary to secondary break flow into the ruptured steam generator. The time required to limit the primary to secondary break flow for an SGTR event is more critical than the time required to cooldown to RHR entry conditions.

Because of these time constraints, these valves and associated flow paths must be OPERABLE from the control room.

The number of SGARBVs required to be OPERABLE from the control room to satisfy the SGTR accident analysis requires consideration of single failure criteria.

Four SGARBV are required to be OPERABLE to ensure the credited steam release pathways available to conduct a unit cooldown following a SGTR.

For other design events, the SGARBVs provide a safety grade method for cooling the unit to residual heat removal (RHR) entry conditions should the preferred heat sink via the steam bypass system or the steam generator atmospheric relief valves be unavailable.

Prior to operator action to cooldown, the main steam safety valves (MSSVs) are assumed to operate automatically to relieve steam and maintain the steam generator pressure below design limits.

MILLSTONE - UNIT 3 8 3/4 7-7 Amendment No. UJ, 0544

I j

PLANT SYSTEMS BASES 3/4.7.1.6 STEAM GENERATOR ATMOSPPERIC RELIEF BYPASS LINES (continued)

Each SGARBV line consists of one SGARBV and an associated block valve (main steam atmospheric relief isolation valve, 3 MSS *MOV18A/B/C/D).

These block valves are used in the event a steam generator atmospheric relief valve (SGARV) or SGARBV fails to close.

Because of the electrical power relationship between the SGARBV and the block valves, if a block valve is maintained closed, the SGARBV flow path is inoperable because of single failure consideration.

The bases for the required actions cea be found in NUREG 1431, Rev. 1.

The LCO APPLICABILITY and ACTION statements uses the terms " MODE 4 when steam generator is relied upon for heat removal" and "in MODE 4 without reliance upon steam generator for heat removal." This means that those steam generators which are credited for decay heat removal to comply with LC0 3.4.1.3 (Reactor Coolant System, Hot Shutdown) shall have an OPERABLE SGARBV line.

See Bases Section 3/4.4.1 for more detail.

3/4.7.2 STEAM GENERATOR PRESSURE /TEMPERATVRE LIMITATION The limitation on steam generator pressure and temperature ensures that the pressure-induced stresses in the steam generators do not exceed the maximum allowable fracture toughness stress limits. The limitations of 70*F and 200 psig are based on a steam generator RTuor of 60*F and are sufficient to prevent brittle fracture.

j 3/4.7.3 REACTOR PLANT COMPONENT COOLING WATER SYSTEM The OPERABILITY of the Reactor Plant Component Cooling Water System ensures that sufficient cooling capacity is available for continued operation of safety-related equipment during normal and accident conditions.

The redundant cooling capacity of this system, assuming a single failure, is consistent with the assumptions used in the safety analyses.

3/4.7.4 SERVICE WATER SYSTEM 4

The OPERABILITY of the Service Water System ensures that sufficient cooling capacity is available for continued operation of safety-related equip-ment during normal and accident conditions. The redundant cooling capacity of this system, assuming a single failure, is consistent with the assumptions used in the safety analyses.

MILLSTONE - UNIT 3 B 3/4 7-7a Amendment No.,TJJ, 0544

_=

Docket No. 50-423 816550 4

i Millstone Nuclear Power Station Unit No. 3 Proposed Revision to Technical Specification Steam Generator Atmospheric Relief Bvoass Valve Lines (PTSCR 3-27-97)

Backaround and Safety Assessment I

t i

July 1997

+

' U.S. Nuclear Regulttory Commission B16550\\ Attachment 4\\Page 1 Backaround The Steam Generator Tube Rupture (SGTR) margin to overfill analysis assumes that the reactor coolant system cooldown is accomplished with the Steam Generator Atmospheric Relief Bypass Valves (SGARBVs). Currently, Millstone Unit No. 3 i

Technical Specifications do not address the operability of the Stam Generator Atmospheric Relief Bypass Valves (SGARBVs).

Safety Assessment This proposed revision to the Millstone Unit No. 3 Technical Specifications provides a new Technical Specification 3/4.7.1.6 and its associated Bases Section 3/4.7.1.6 for the SGARBVs. The operability of the SGARBV lines provides a method to recover from a SGTR event during which the operator is required to perform a limited cooldown to establish adequate subcooling as a necessary step to limit the primary to secondary break flow into the ruptured steam generator. The time required to limit the primary to secondary break flow for an SGTR event is more critical than the time required to i

cooldown to RHR entry conditions. Because of these time constraints, the SGARBVs and associated flow paths must be operable from the control room. The number of SGARBVs required to be OPERABLE from the control room to satisfy the SGTR accident analysis requires consideration of single failure criteria. Four SGARBVs are required to be operable to ensure the credited steam release pathways available to conduct a unit cooldown following a SGTR.

I For other design events, the SGARBVs provide a safety grade method for cooling the unit to residual heat removal (RHR) entry conditions should the preferred heat sink via the steam bypass system or the steam generator atmospheric relief valves be l

unavailable. Prior to operator action to cooldown, the main steam safety valves (MSSVs) are assumed to operate automatically '.o relieve steam and maintain the steam generator pressure below design limits.

The Westinghouse improved Standard Technical Specifications, NUREG 1431, Rev.1, l

I was used to develop this submittal. The NUREG 1431, Rev.1 surveillance frequency is 18 months. The NUREG 1431, Rev.1 surveillance frequency bases reads " operating experience has shown that these components usually pass the surveillance when performed at the 18 month frequency". The proposed frequency acceptability has been evaluated by reviewing AWO's for 3 MSS *MOV74A/B/C/D for the years Jan.1990 to April 1997 to confirm the absence of excessive work orders which indicate valve functional failures and none were identified. Based on no indication of a valve i

functional failure in the 3 MSS *MOV74A,B,C,D AWO work history for the above period, it is concluded the proposed surveillance frequency is acceptable. Additionally, each SGARBV line consists of one SGARBV and an associated block valve (main steam atmospheric relief isolation valve,3 MSS *MOV18A/B/C/D). These block valves are used in the event a steam generator atmospheric relief valve (SGARV) or SGARBV 1

fails to close. Because of the electrical power relationships between the SGARBV and

U.S. Nuclear Regulatory Commission B16550\\ Attachment 4\\Page 2

. the block valves, if a block valve is maintained closed, the SGARBV flow path is inoperable because of single failure considerations.

Based on the above, this proposed change to the Technical Specifications of Millstone Unit No. 3 is considered safe and does not constitute a unreviewed safety question.

i l

l 1

i 1

i Docket No. 50-423 B16550 Millstone Nuclear Power Station Unit No. 3 Proposed Revision to Technical Specification 4

Steam Generator Atmospheric Relief Bvoass Valve Lines i

(PTSCR 3-27-97)

Sianificant Hazards Consideration and Environmental Considerations i

l July 1997

l l

'U.S. Nucl:ar R::gulatory Commission B16550\\ Attachment 5\\Page 1 Sionificant Hazards Consideration NNECO has reviewed the proposed revision in accordance with 10CFR50.92 and has concluded that the revision does not involve a significant hazards consideration (SHC).

The basis for this conclusion is that the three critoria of 10CFR50.92(c) are not satisfied. The proposed revision does not involve an SHC because the revision would not:

1.

Involve a significant increase in the probability or consequence of an accident previously evaluated.

The operability of the SGARBVs provides a method to recover from a SGTR event during which the operator is required to perform a limited cooldown to establish adequate subcooling as a necessary step to limit the primary to secondary break flow into the ruptured steam generator.

For other design events, the SGARBVs provide a safety grade method for cooling the unit to residual heat removal entry conditions should the preferred heat sink via the steam bypass system or the steam generator atmospheric relief valves be unavailable. This proposed revision to the Technical Specifications will add a new Technical Specification 3/4.7.1.6 and its associated Bases Section 3/4.7.1.6 which were developed based on the information contained in the Westinghouse improved Standard Technical Specifications, NUREG 1431, Rev.

1. The

)

proposed specification and bases provide further assurance that the SGARBVs will be available to tunction as described in the accident analyses.

Therefore, the proposed revision does not involve a significant increase in the probability or consequences of an accident previously evaluated.

2.

Create the possibility of a new or different kind of accident from any accident previously evaluated.

Tb:s proposed revision to the Technical Specifications to add a new specification and bases for the SGARBVs does not cause a change in the operation of any system or component during normal or accident conditions.

Therefore, the proposed revision does not create the possibility of a new or different kind of accident from any accident previously evaluated.

3.

Involve a significant reduction in a margin of safety.

The proposed new Technical Specification 3/4.7.1.6 and its associated Bases Section 3/4.7.1.6 were developed based on the information contained in the Westinghouse Improved Standard Technical Specifications, NUREG 1431, Rev.

1. The SGARBV's are not currently in the Technical Specifications of Millstone Unit No. 3 and are being added to ensure accident mitigation functional capability. The NUREG 1431, Rev.1 surveillance frequency is 18 months. The

1 l

'U.S. Nucl=r Regulatory Commission B16550\\ Attachment 5\\Page 2

]

' NUREG 1431, Rev.1 surveillance frequency bases reads " operating experience has shown that these components usually pass the surveillance when performed at the 18 month frequency". The proposed frequency acceptability has been evaluated by reviewing SGARBV AWO's for the period from Jan.1990 to April i

1997 to confirm the absence of excessive work orders which indicate valve i

functional failures and none were identified. Additionally, each SGARBV kne consists of one SGARBV and an associated block valve. These proposed j

changes are consistent with the design and operation of the SGARBVs. There is no negative affect on the dose consequences from any design basis event or core damage frequency.

Therefore, the proposed revision does not involve a significant reduction in a margin of safety.

In conclusion, based on the information provided, it is determined that the proposed revision does not involve an SHC.

Environmental Considerations NNECO has reviewed the proposed license amendment against the criteria of 10CFR51.22 for environmental considerations. The proposed revision does not involve an SHC, does not significantly increase the type and amounts of effluents that may be released offsite, nor significantly increase individual or cumulative occupational radiation exposures. Based on the foregoing, NNECO concludes that the proposed revision meets the criteria delineated in 10CFR51.22(c)(9) for categorical exclusion i

from the requirements of an environmental considerations.

l 1

4 J

I i

l t

+ - - - -

r--

P-'

v

Retrieved from "https://kanterella.com/w/index.php?title=ML20149J349&oldid=4166535"